# Tech Tricks: Homemade Balance Charging Cradles.



## Conte (Jan 14, 2010)

_*Some of you*_ might recognize one of these units.







It's a typical multifunction hobby charger.
It's a great investment to the avid flashlight enthusiast as it can pretty much intelligently charge any battery or pack we'd have in our arsenal, from NiCD to LiFepo4. This particular model can be had on the Bay for about $50. I power it with an IBM laptop adapter that gives me plenty of voltage and current for most all my charging needs. 16v 4.5a to be exact.

One disadvantage is that it has but a single main output. This is not a problem for charging assembled packs that are designed to have the cells gang charged, but when you want to top off your set of Li-Ions so that your ROP or Mag 11 is ready to rip later on, you are pretty much limited to doing it one cell at a time.

If you can connect more then one at a time, you can charge them together, but as most battery geeks will tell you, better they each get their own attention. I've noticed the new LiFepo4 cells in particular can be sensitive, yielding different state of charge readings, fresh of the charger when charged together in series.






Most of the good hobby chargers will feature these special connectors, designed to establish control over each cell in a specially made lion/lipo/life pack. The pack will have a special charge connector to plug into these sockets.

Using grade school arts and craft skills, and some basic soldering skills, I have exploited this feature, effectively turning my charger into bank charger.






Here I have a set of 3 LiFe cells charging using the Balance charge function.






I took 4 C-Cell battery holders, cut them in half and glued them to a sheet of acrylic spacing the halves to accommodate 65mm cells.






I then wired the leads and the charge connector across this terminal strip. It has some nice lugs for me to connect my chargers alligator clips to while selecting the number of cells I wish to charge. As labeled, the Common Negative is the the left. Then from left to right I can select 1s, 2s, 3s, and 4s.






The festivities do not end there. As the cradle is sized for 65mm cells, it can also be used to bank charge 18650 lions. Seen here it's topping off my IMR for my EDC. You can unplug the balance connector and select 1s for single cell operation.

*NOTICE:* Make sure you read your chargers instruction manual, and double check your connections. As you are manually selecting your cell configuration there is a margin for error, and some chargers REALLY won't appreciate being hooked up wrong. For example, my chargers manuals warns that you might damage it, if you attempt to start a charge with the balance connector plugged in, but without the alligators connected properly.






*Today* I want to make a cradle to accommodate my shiny new AW IMR26500 cells that I just got in the mail to power my Megalennium 2x26500.

The ingredients are: one charge connector, a 3 point terminal strip, 2 C-Cell holders, and piece of acrylic.






Acrylic is pretty easy to work with. In Canada you can usually purchase it from your local Home Hardware for not lots of money.
To cut it you use a metal straight edge and a sharp knife. I'm using a pen knife. 

When you figure out where you want to make your cut you run the knife along the straight edge to give it a nice score mark. If you can, run it over a few times.






Once you have your nice score mark, simply locate the mark along the edge of your desk or work bench like so, and snap it off.

Easy Peasy.






I originally attempted to construct these units using Hot Glue, aka: Glue Gun Glue. This did not work very well. Though it seems to stick to acrylic really well it did not hold up in use. The terminal strip on my 2x50mm cradle came loose, and the first two most used slots on my 2x65mm also fell apart during a charge.

I rebuilt the units using epoxy, it really is the best way to go for this setup. 






Once we get it all together, it's ready for wiring.
This step will require basic soldering skills. If you are not confident soldering, I recommend lobbying the services of someone who is.
After all, sloppy work here could cost the lives of your batteries or your charger, and who knows what other collateral damage.

If you are new to soldering and can do a decent job, this may very well be a good beginner project. Just make sure to check and double check your work before using it, and maybe run a multi meter over it checking for continuity and resistance to confirm there are no cold solder joints. Also, if you are using the same kind of terminal strip as I am, watch out when you solder to the lug that is also used for mounting as it may soften the glue and come loose on you.

*TIP:* Soldering is like buttering toast. You use the knife the apply the cold butter to Hot toast, causing the butter to melt into the toast. You DO NOT, use a Hot knife to melt butter onto cold toast.

The idea with soldering is that you are using the iron to heat up the lug and the wire, then touch the solder to it, thereby the heat of the lug and wire causes the solder to melt and fuse to it. A common beginner mistake is to melt the solder with the iron and attempt to apply it. The correct method will almost always assure a good solder joint.






Here is the Wiring Diagram provided in the chargers manual. It lays out for you, pretty clearly (at least to an experienced tech like Me), how to wire up our charge connector. I imagine your charger manual might also feature such a schematic. This particular schematic SHOULD apply to most chargers as the balance Charger connection is a Industry Standard.






Here is the finished product. I used the centre lug as the common negative, and the adjacent lugs on either side for 1s and 2s connections, then labeled it as such.

If you prefer, feel free to stick to a more linear layout, it's jsut tech instinct to assign the common negative to the mounting lug. 

The terminal strip I used is alot smaller then the one use on my 65mm 4s cradle, so I will use caution to make sure the alligator clips do not touch each other or any contacts they are not supposed to.

When sourcing out charge connectors, I recommend getting some that can accommodate the maximum amount of cells you may be building a cradle for. Chances are they will come in a lot.

I got a 10 pack for about $5.
The sockets in my particular charger are backwards compatible, and don't much care how many cells are plugged in at a time, as long as they are in proper order. You can remove extra pins from the connector and tailor it to your needs.

In my case, I bought a lot of 4s connectors off the Bay, and removed two pins to make a 2s connector, and my charger doesn't' mind that it is plugged into the 4s slot.






Here I have successfully built a 2 bank charger for my IMR cells.

All parts were sourced from Ebay: 
The Battery holders were about 6 for $5.
The connectors were about 10 for $5. Search "balance charger plug". 
I forget how much I paid for the Acrylic at Home Hardware.
And the terminal strip could be found in lots for about $1 each. Search: "terminal strips".

One of these cradles likely costs less then 5 dollars. Once you have a lot of supplies as I do, you could build all sorts to accommodate your various battery charging needs.






Seen here I chopped a single D-Cell holder, into 3, to create a cradle to charge five 1/2D cells, for dropping 6volts into a 3D Mag, for running Magcharger or Wa1160 bulb.

*IMPORTANT SAFETY NOTICE:*

These designs have no official safety certification, as such their limits are unknown. It is up to the individual user to verify and monitor their safe operation. Many CPF members will have the experience necessary to construct and safely use these units, and this post is for their benefit. 

If used incorrectly or overloaded they could very well pose a fire hazard. For this reason, I advise you build and use one of these units _at your own risk_.

Unless you have a good idea of the limitations of the particular components used in one of these builds I would recommend limiting the applied current battery holders with stock leads to 1amp. As the leads that came with my battery holders are very flimsy, chances are this current spec will be safe for any other variation of this build.
In use I've noticed some mild warmth coming from the battery holder leads when 2amps is applied. This does not last long, as no matter what current level I would set, the smart charger would throttle down the current to about 1.1amps, and did not seem to want to push any more then that through the flimsy leads.
I can only imagine the charger detected insufficient plumbing and compensated. 
*
Upgrading and Revisions.*

If you like this design, and use it regularly . . . AND are confident with your soldering skills, you may consider upgrading the leads to up the charge rate and assure an overall safer operation. I found this necessary as I was unable to get the charge rates I wanted with the stock battery holder leads. 

This requires some quick and confident solder welds as the plastic of the holder is likely to melt very easily. 
I'm upgrading my cradles using 18 gauge solid wire. The solid wire was chosen mostly for the fact that I already had some on file. Solid wire is capable of conducting more efficiently then stranded wire. As these cradles have a solid frame and don't really need to be shock rated, it's not a bad idea.

18 gauge wire is rate for 3 amps conservatively, and due to the very short distance and low voltages it could easily handle more in this application.
If you are looking to go up to a 10 or more amp charge I would consider using 14 gauge while also rigging it to bypass the stock battery holder contacts as seen here. 






Upgrading the positive contacts, I pushed a stripped section of the wire though the battery holders contact holes and bend the exposed section. 






I then pulled the wire back and made a quick solder weld to the contact.

This is the part where you have to be careful as the heat for the weld has likely started the plastic melting regardless of how fast you were. 






A "tool" handy for this procedure is some "parts chiller" Basically a freezing action spray. 
Once I made the weld, while carefully holding everything in place, I took the chiller and sprayed it onto the spot where I had made the weld, solidifying the plastic before it could slip and ruin the holder. You would otherwise have to hold the wire in place until everything cooled down.
If you don't have any boutique parts chiller, you can just use computer "air spray" tilting the can sideways so that the raw liquid sprays out. This is pretty much the same thing as parts chiller. 

The other option, if you wish to avoid soldering all together, is once you have the bent wire in place on the inside of the battery holder contact, so simply glue the wire in place on the outside of the holder. I have not tried this personally, but with the right glue and proper technique it could be a good idea. 






To make the negative contact you pretty much go through the same motions. The difference being that you would pinch the negative wire on the end of the spring like so. This would bypass the spring avoiding any dependency the circuit has on its quality or conductivity. 






Afterwords, as the spring offers some thermal isolation from the plastic, it is considerably easier to apply solder without the risk of meltdown. 
Once again, if you wish to avoid soldering, you can just pinch the wire onto the end of the spring without the need for solder. 
Mind you, the solderless methods are likely to work with solid wire only. 






Here we have the revised finished product. I like how the solid wire allowed me to shape it into a more uniform layout. 

*As discussed* in this thread, these particular methods using balance charging systems might be somewhat redundant.
In the case of the 2x50mm cradle, a parallel system might be a better and less complicated way to go. 
On the other hand, I find balance charging method advantageous in the 4x65mm cradle when I wish to hit more then 2 cells with a high rate charge. As my particular charger is limited to about 4 amps due to the powersupply used, I would be unlikely to hit 4x26650 LiFe cells with a 1C charge using the parallel method. 

*
The Lux Luthor Magnet Method. *







Since the creation of this threat, Lux Luthor brought to my attention another great way in which to utilize the Balance Charging system. 
I've decided to try my hand at it.

If you live in Canada, you are likely familiar with the Home Hardware. My local A&J Home Hardware on Bouchard street in Sudbury can be a modders paradise, as they will custom cut you wire or pipe, have a workbench where they help you rough fit projects, and have the stock consistency of a nation wide chain store.

In their limited stationary supply section I was delighted to find they stock just the perfect kind of magnet we need for this project.
As this is a nation wide chain, these magnets should be available, (if by special order) at any home hardware across Ontario, and even Canada I would imagine. 
This package cost $7.49cdn +tax.






As you can see, I constructed a 4S harness using 6 magnets. 
Five for the BC connector (Balance Charge) and the common Negative;






and one for the floating Positive:






This idea is, you can snap on as many BC connector leads as you need to match your cell count.






Seen here, I have snapped together 3 cells for the charge. The Blue 3s wire being the last in the chain, snapping the floating posative onto the end of that chain, and omitting the Green 4s lead. 






The insulated side of the battery seems a good place to snap the omitted lead magnet. It should stay out of trouble there. 






With the remaining Magnets, I soldered up some parallel jumpers so I can use that particular method of charging for a pair of cells. 
In this configuration, the omitted magnets are just all snapped together in their standby positions on the negative common side, while *the BC connector is not plugged in.*

The tricky part of the rig is the soldering. Too much heat applied to the Magnet can strip it of its magnetization rendering it useless. I've known this for a while. It's common knowledge among competent guitar techs that the use of high output soldering guns has been known to demagnetize electric guitar pickups. 

Lux has mastered it, and has dropped tips among the forum. I myself have been soldering for over 16 years, and have the right equipment, so though reluctant to damage the magnets, I figured I could handle it. 

The trick is to be quick, avoiding to much iron time on the magnet. You pretty much have to know how to solder and have decent experience doing so.
Refer to the "Butter on Toast" tip mentioned earlier in the thread. In this case, imagine using a blow torch to heat the bread just enough so that the butter melts into it, but without actually toasting it. 

The method is something to be seen. I have made this HD video to illustrate. 





If you can do the motions as seen here, you should be able to pull it off.

What you are seeing is:
A: I "tin" and preheat the wire for soldering,
B: I tin and preheat the magnet surface ",
C: I fuse the preheats and tinned parts together,
D: I quickly spray some "chiller" on the magnet to remove all access heat. 

Tinning in the process of pre-fusing some solder onto the surfaces to be connected, as you would with contact cement glue, or even epoxy.
It's pretty much a mandatory prerequisite to making a good solder joint. 


For tools:
- I have a set of jaws or "helping hands" to hold everything,

- A 35watt soldering iron. Note the medium flat tip used. Too sharp a tip might not spread the heat evenly. To wide may spread it too much making it hard to focus your
heat and overheating the magnet. The right tip could make or break this joint, you should be good with a fine tip though. A 35-45 watt iron with a med flat tip is pretty much a swiss army knife of irons to those who can use them well. *DO NOT, use a solder gun!*

- Some FINE standard Rosin Core solder. Nothing special but the size. Too thick could flood your joint making for a sloppy work. 

- Parts chiller. The chiller has been discussed already, look for the pic of the can.

I was able to pull this off in one shot with no damaged magnets. 
If you are not confident doing this, I would practice on some random pieces of metal. Maybe try soldering to the edge of a penny as they are about the same mass as the magnets, just keep in mind, It will take about half the time to fuse to the magnet as it would to the penny. I would recommend soldering to the edge of the magnets as it will take longer for the heat to spread across then it would if you soldered to middle. For soldering the common negative, fuse the main lead and the BC lead together before welding to the magnet so that you only have one joint to make. 

Last but not least, mind the polarity. When you stack the magnet, they will only snap together one way, if you want your wires to be oriented a certain way, best to figure out how they will snap together before making the connections. 

ENJOY !


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## Conte (Jan 14, 2010)

Thread reposted due to accidental deletion.


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## LuxLuthor (Jan 14, 2010)

Nice job and photos, Conte. 

For references only, 

Here was the old thread where we adapted a German Voltcraft cradle.

And a more recent one where I found using magnets to be quick, work with any battery (except the A123 with non-ferrous can), and small package.


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## kramer5150 (Jan 14, 2010)

I have a similar charger, and charge my individual 26650 & 18650 cells in parallel. It works great with CC/CV chargers like this one that terminate at 4.2. FWIW, I also use a Lenovo 15V laptop P/S and it works great.


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## Conte (Jan 14, 2010)

Good reference Lux, The magnet method is pretty slick and defiantly as modular as you can get. 

The only aspect of that I'm a bit sketchy on, is, since the Pos and Neg leads are permanently soldered to the first and last S lead, how do you scale it down for less cells ? Without cutting a while new harness ?

I you haven't already, (I didn't see it mentioned or illustrated in your thread), what I'd do, is get one more magnet, and solder JUST the pos leads to it. Then after you can scale the harness down, and sandwich the Pos magnet to whatever the Last S magnet is. 

It never occurred to me to use magnets to connect batteries until I met some of your posts. Now I use them to attach batteries for experimental purposes. 



> I have a similar charger, and charge my individual 26650 & 18650 cells in parallel. It works great with CC/CV chargers like this one that terminate at 4.2. FWIW, I also use a Lenovo 15V laptop P/S and it works great.



Ah, that's how the normal bank chargers work, eh ?
I was never sure if I should trust that method. The normal bank chargers run a pretty low C-Rate. If I wanted to charge each cell at a High - C rate, I'd have to dial in a 2xC rate for two batteries in Parallel.
What C Rate do you feel comfy hitting a parallel system with ?

Seems you had the same idea in how to chop up a Battery Holder. 

You idea is a good supplement to this thread. 

PS: My Charger came with a cheap PSU that broke. Having a spare adapter for my laptop saved the day.


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## InHisName (Jan 14, 2010)

I am just discovering these 'hobby' chargers. Can NiMH AAs be connected in same fashion and charged successfully with these type of chargers ? This seems like the only way to speed up charging one cell at a time and still do a decent job of it. I have a C9000 but on occasion I want to charge more than 4 at a time.


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## LuxLuthor (Jan 14, 2010)

Conte said:


> Good reference Lux, The magnet method is pretty slick and defiantly as modular as you can get.
> 
> The only aspect of that I'm a bit sketchy on, is, since the Pos and Neg leads are permanently soldered to the first and last S lead, how do you scale it down for less cells ? Without cutting a while new harness ?



Since you can use the 6 cell (7 balance wires) plug for any number of cells from 1 through 6, you could just use the 7 wire plug going to magnet wires to correlate with the number of cells.

Like in your example photo below where you used the 4s plug, with 3 wires to charge your 2 cells, I would just use those same right most 3 wires going to the 3 magnets. Then I have the main power aligator clips going to another outside larger red/black wire for main charging power. 






Just imagine where you are showing the two empty plug slots, you had wires in those slots, but those extra 2 wires were not being connected to anything. That would be how I would treat those two wires with magnets soldered on them. If I wanted to charge 3 cells, then I would bring the 4th magnet wire into play; 4 cells, the 5th magnet wire. This photo in my thread shows all the wires being used.


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## rmteo (Jan 14, 2010)

Conte said:


> ..... I was never sure if I should trust that method. The normal bank chargers run a pretty low C-Rate. If I wanted to charge each cell at a High - C rate, I'd have to dial in a 2xC rate for two batteries in Parallel.
> 
> What C Rate do you feel comfy hitting a parallel system with ?



Charging Lithium cells (of the same type) in parallel works well. I charge 8x 16340 (650mAH capacity) at 5A (max. charging current of the charger) which is just a bit less than 8C.


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## SilverFox (Jan 14, 2010)

Hello Conte,

Glad to see you were able to get this thread back up... after I accidently deleted it.  

At any rate, nice set up, and nice write up.

Tom


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## SilverFox (Jan 14, 2010)

Hello Rmteo,

While 5 amps is close to 8C for one 650 mAh cell, when you parallel them as you have it is actually just under 1C for the battery pack.

Tom


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## Black Rose (Jan 16, 2010)

I don't have a hobby charger yet, but I think I am heading in that direction with the different Li-Ion cells I am getting.


Conte said:


>


 
Would it be possible to get a photo of the back of that terminal strip?
I'm :thinking: on how it's connected to the back.


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## Mr Happy (Jan 16, 2010)

Black Rose said:


> Would it be possible to get a photo of the back of that terminal strip?
> I'm :thinking: on how it's connected to the back.


The balance leads go to each of the cell connection points in order, like this (order is important):

```
Charge + ==================
                          |
Balance 3 ----------------+
                          |
                          -
                         | | Cell #2
                         | |
                         ---
                          |
Balance 2 ----------------+
                          |
                          -
                         | | Cell #1
                         | |
                         ---
                          |
Balance 1 ----------------+
                          |
Charge - ==================
```
(The main charging wires are not shown in the photo.)


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## LuxLuthor (Jan 16, 2010)

Black Rose said:


> I don't have a hobby charger yet, but I think I am heading in that direction with the different Li-Ion cells I am getting.
> 
> 
> Would it be possible to get a photo of the back of that terminal strip?
> I'm :thinking: on how it's connected to the back.



It also appears to me that Conte is not using a 2 cell balance charging setup here. He has the two cells in parallel, essentially becoming a large mAh single cell. A single cell does not need a balancer plug at all, just the outer red/black main current leads.

Balance charging as Mr Happy demonstrates assumes 2 or more cells are in series. If this was to be a balancing setup, the black and yellow wires would need to be reversed in the white plug. Then the yellow wire would need to be going in between the two cells. I am showing how it should look in Conte's example using my magnet leads.






Why would you want to do balance charging instead of putting all cells in parallel (which can be done if you have no balance charging capability)? To save time charging. My above setup is charging cells up to 2300mAh which goes a lot faster than up to 4600mAh


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## Conte (Jan 16, 2010)

> It also appears to me that Conte is not using a 2 cell balance charging setup here. He has the two cells in parallel, essentially becoming a large mAh single cell.



:thinking: . . . No, that's a series balance setup. 



> Why would you want to do balance charging instead of putting all cells in parallel (which can be done if you have no balance charging capability)? To save time charging. My above setup is charging cells up to 2300mAh which goes a lot faster than up to 4600mAh



Not to mention it also gives the charger control over each cell, enhancing charge quality. 


I could take a picture of the back of the terminal strip if you really want, but it wont' tell you much, a schematic is really the was to go.
The picture I took of the manual is the schematic you want to use. 

Mr. Happy's schematic is good too. I just of drawn it upside down to match the perspective of my chargers balance plugs, as the wires are not actually labeled. That's just my charger tho, others could very well be the other way around.


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## LuxLuthor (Jan 16, 2010)

As an instruction guide for newbies, it becomes confusing to not keep red as positive, black as negative. I'm not seeing in this view with the wires soldered to those terminals how you are using the same middle lug as "common negative," as you said below pix going from 1s to 2s.



> Here is the finished product. I used the centre lug as the common negative, and the adjacent lugs on either side for 1s and 2s connections, then labeled it as such.



You can see by Black Rose's question, and my interpreting this as a 1s2p setup that it isn't making obvious sense as shown. I don't doubt that you have a way to hook it up properly, but it is confusing when you cannot follow each wire if someone wants to copy what you did--which I assume was your intention in making this thread. 

Two other opinions:


Charging identical cells in parallel will work out just fine with Lithium cells, so I'm not sure what you think you are gaining when you say you are enhancing the charge quality.


if you use those holders, they have high resistance (which accumulates in series) & the springs heat up, so it doesn't work well with higher amp charge rates. The 1 Amp you mentioned in your first post will be fine.
The nice thing about using Lithium Manganese or Lithium Iron Oxide safe chemistry cells is that you can charge them at much higher rates. The RCC guys fast charge them in 10-15 mins, so you need low resistance contacts/wires for that.​Again, thanks for your work in doing the thread and taking photos.


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## rmteo (Jan 16, 2010)

Conte said:


> ...Not to mention it also gives the charger control over each cell, enhancing charge quality.



Balance charging is used with *series connected battery packs* that cannot be disassembled for charging such as this 3S1P rated at 2200mAH, 20-30C discharge rate:






When you are discharging the pack at 60+A, you want to be sure the cells are balanced. Balance charging does not necessarily enhance charge quality.


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## Benson (Jan 16, 2010)

Cool idea, using a laptop PSU -- I've been planning to get a hobby charger "at some point" for a while now, and as I have a spare 90W power brick, that's one more piece taken care of.


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## Conte (Jan 17, 2010)

> As an instruction guide for newbies, it becomes confusing to not keep red as positive, black as negative. I'm not seeing in this view with the wires soldered to those terminals how you are using the same middle lug as "common negative," as you said below pix going from 1s to 2s.



Ah I see what you are saying. Ok, I'll update it with a better pic of hookup. 
I thought I had it covered with the pictures of the 4x65 cradle. The 2x50 cradle was mostly featured to show construction methods. 



> Charging identical cells in parallel will work out just fine with Lithium cells, so I'm not sure what you think you are gaining when you say you are enhancing the charge quality.



I used the term loosely. I hadn't before considered a parallel charge. 
I had been charging them in series before for the most part, and as mentioned, I noticed "the new LiFepo4 cells in particular can be sensitive, yielding different state of charge readings, fresh of the charger when charged together in series." Hence why, for my application, it enhances the quality of charge. 

I admit, the 2x50 cradle is somewhat redundant, and parallel charging might be a better option for 2 cells. I would of made it 4 cell but I only had 2 holder left of the 6 pack.

Since my particular charger is limited to about 4a of current, parallel is not as feasible for me when charging more then 2 cells, which is what persuaded me to take this route.



> if you use those holders, they have high resistance (which accumulates in series) & the springs heat up, so it doesn't work well with higher amp charge rates. The 1 Amp you mentioned in your first post will be fine.



I'm aware, I was disappointing when I get the holders in, and found them to have such flimsy leads. They are the the biggest weak link right now. I'm confident those springs could probably handle the 1C charge I generally tend to use but at the moment I can't seem to get the charger to push more then 1.5a thru the cradle. I set it to 2.3a, it's starts at 2, then drops to 1.5, then drops further averaging most of its charge at about 1.1a. I believe I felt warmth on the leads at 2a.

I think the "smartness" of the charger is detecting a deficit in the plumbing it has to work with and is throttling down automatically to match it. I knew the leads were going to limit me, but it's just ridiculous. There is not gauge listed on the wire so I was unable to predict their load and resistance values. 

At this point, I do believe I will be upgrading the cradles with some higher gauge leads. Once I have completed this revision, I will add it to this thread as an upgrade option. 

I'm glad you appreciate it. I didn't really make this as a n00b how to guide like my other posts. More of an idea share among tech geeks, after all, unless the newbie can solder well, read a schematic, and has a basic understanding of electronics, this is already above their scope.


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## Wallace L (Jan 17, 2010)

I am a newb to CPF and am building a balancing setup for charging with my e-station BC6 charger. 

I am in need of 4 pairs of magnetic leads like those previously offered by LuxLuthor with the purchase of cells from him.

How can I go about obtaining these ?


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## LuxLuthor (Jan 17, 2010)

All makes sense. Thanks for additional feedback! Always good to share ideas back and forth! :thumbsup:


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## Conte (Jan 25, 2010)

*Revisions Made. *


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## Hack On Wheels (Jan 25, 2010)

Wallace L said:


> I am a newb to CPF and am building a balancing setup for charging with my e-station BC6 charger.
> 
> I am in need of 4 pairs of magnetic leads like those previously offered by LuxLuthor with the purchase of cells from him.
> 
> How can I go about obtaining these ?



I'm in more or less that same boat, as I'm looking into putting together a hobby charger setup for probably up to 6 cells... I don't believe you can readily purchase magnetic leads. You can do it yourself if you are skilled with a soldering iron; I've read that you can ruin the magnetic ability of the magnets if you aren't fairly quick with your soldering.

That's another reason why some go for the cradles; I know I can manage to make one like Conte's even with my rough soldering. The magnetic leads are still an attractive option though, it really doesn't get more flexible or compact!



Conte said:


> *Revisions Made. *



Thanks for keeping this thread updated, it's a really great guide and has given me a bunch of ideas for my own eventual setup. lovecpf


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## Conte (Jan 27, 2010)

*Lux Luthor Magnet Method added.*

What say you, Mr.Lux ?


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## Black Rose (Jan 27, 2010)

Another magnet option for Canadians is Lee Valley tools (if you have one nearby).

They have a good selection of rare earth magnets.


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## GarageBoy (Jan 29, 2010)

Magnets dont mess up the batteries?


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## Conte (Jan 29, 2010)

No, hasn't seemed to have been a problem, and I think Lux has been doing it a long time.


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## gigasquid (Jul 1, 2011)

Amazing thread Conte - thank you for the time and detail you put into this. Definitely on my project list :thumbsup:


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## benckie (Jul 27, 2011)

here is revision 2 on the 2s balance charge lead set up for 18650's i had to cut the springs in the battery boxes as they are for none protected cells and I'm using protected cells so to get them to fit i had to remove the spring and reverse the polarity of the battery boxes (run the batteries the other way round) i have also made some singular ones for protected cells and use red heat shrink to cover the black wires and black heat shrink to cover the red wires so there is no confusion witch way the battery goes.

here is a pic of the 2s balance charging set up












here is a pic of the single 18650 ive been using.






this is a 3s1p protected charge box i brought off fleabay its only good for unprotected cells, but has built in protection, over voltage under voltage plus a few other features.






I'm waiting on some more bits to make 3s balance charging leads and a 6s balance charging lead for the 18650 batteries, ill post up some pictures of them once the bits get here, got to practice soldering magnets.


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## benckie (Aug 3, 2011)

revision 3 for charging

single






2 cell balance charge






3 cell balance charge






just waiting on some more parts to make a 6 cell balance charging lead.


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## benckie (Aug 6, 2011)

this would have to be a great one

http://www.hobbyking.com/hobbyking/store/__14856__Parallel_charging_Board_for_6_packs_2_6S.html

if you made your own balancing leads, you could charge from 12 to 36 li-ions at one time, or 6 x 2s up to 6 x 6s lipo,s you would need a charger with a 6s balance port and atlest 10 amp charge rate, or 20 amp charge like the icharger 208,s

i use that parrallel charging board for my lipo,s for my rc truck, with a icharger 106b+ and a p350 power supply


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## jhn.holgate (Aug 6, 2011)

Great thread, thanks guys. A couple of home made cradles in parallel for my 18650's....


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## DasFriek (Aug 7, 2011)

Im glad i found this thread as ive had my Hyperion 720i charger about 2 months now and mainly just do test cycles for capacity and rely on my Pila to charge cells since i have nothing set up for mass cell charging.
But i do have a question, How well do these cradles setup with the balancing leads handle discharging?
Does it just do a basic discharge, Or is it just as reliable as a single cell discharge cycle when using the balancing leads?

My main goal is to cycle many of my Li-Ion cells which tend to increase in capacity when new after a few cycles.

Im not sure which way i want to go on building a way of using my balancing leads as i do prefer cradles over magnets, But each has its good and bad points. I do know im not to fond of just hooking them in series or parallel and charging multi cells in that manner as you loose control of everything since the charger just sees one large battery.
Thanks for all the work in doing up this thread and pics as it should make my build easy, Especially i was just never gonna build a setup for multi cell balancing. Now i can get the full use of my charger and can see up to 6 cells graphs all running on my laptop as the charger does its job.


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## KiwiMark (Aug 7, 2011)

benckie said:


> this would have to be a great one
> 
> http://www.hobbyking.com/hobbyking/store/__14856__Parallel_charging_Board_for_6_packs_2_6S.html


 
Looks pretty similar to http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=15237 which I have ordered with my 208B and should arrive Monday or Tuesday. I don't normally parallel charge, but I figure there will be times that I want to get more batteries charged in a hurry and being able to charge 2 or 3 or 4 at once couldn't hurt. I have plenty of those T connectors and alligator clips to make more charging leads as required.


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## LuxLuthor (Aug 7, 2011)

DasFriek said:


> Im glad i found this thread as ive had my Hyperion 720i charger about 2 months now and mainly just do test cycles for capacity and rely on my Pila to charge cells since i have nothing set up for mass cell charging.
> But i do have a question, How well do these cradles setup with the balancing leads handle discharging?
> Does it just do a basic discharge, Or is it just as reliable as a single cell discharge cycle when using the balancing leads?
> 
> ...



I think either cradle or magnets with serial balance leads or as one big parallel capacity will all work fine with discharges, as long as you are using the thicker main wire leads. The coating on the magnets of course has some resistance if you are using them to join cells in series or parallel, but if contact surfaces are clean, I have discharged cells connected with neodymium magnets at 10 Amps without noticing any resistance related heat with them. 

I like the KJ Magnets which are durable, and triple coated with Nickel-Copper-Nickel but you can see there are comparative limits when using various metals.


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## DasFriek (Aug 7, 2011)

Im kind of lost on this wire and plug wise.
These are the boards and adapter wire that came with my Hyperion 720i.
Do i need to use the board, Or can i cut the wires going into it and build my leads from that?
Or do i need a 7S plug that goes into the board from a battery pack?
And i included pics of both boards i have in case one is more useful than the other.

My goal is to build something from a 7S balancer set of wires and just use what i need. But im not sure what set of wires should be used to start from.
If i need a certain plug can you point me to one that is exactly what i need so i have no confusion.


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## benckie (Aug 7, 2011)

KiwiMark said:


> Looks pretty similar to http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=15237 which I have ordered with my 208B and should arrive Monday or Tuesday. I don't normally parallel charge, but I figure there will be times that I want to get more batteries charged in a hurry and being able to charge 2 or 3 or 4 at once couldn't hurt. I have plenty of those T connectors and alligator clips to make more charging leads as required.


 
same thing, just with deans plugs (t connectors) just makes sure the batteries voltages are close

i like mine, but you must only plug batteries into it that have the same voltage and the same cell count, i only use mine when i use my rc car and ive run down say 4 batteries and they have all come off the same low voltage cut off and are pretty much the same voltage.

becuase this parrallel board is great but only for charging match cells with the same voltage after being discharged and the same cell count meaning you can either parallel ballance charge all 2s or all 3s to 6s but you can not mix a 2s and a 3s together, for this reason and for safety i balance charge in series.


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## jhn.holgate (Aug 7, 2011)

> My goal is to build something from a 7S balancer set of wires and just use what i need. But im not sure what set of wires should be used to start from.
> If i need a certain plug can you point me to one that is exactly what i need so i have no confusion.


Mine is the same sort of thing - I'm going to keep my board intact because I have various LiPoly battery packs with the balancing leads already attached. But I've ordered some JST-XH extension leads - I figure I'll just cut the end off that I don't need and solder some ring terminals to suit my battery setup. You can get extension leads in 2-7s in packs of 10 for a few dollars from here: http://www.hobbyking.com/hobbyking/store/__9735__JST-XH_2S_Wire_Extension_20cm_10pcsbag.html 

It can probably be wired up straight to the balancing plug in the charger, bypassing the board altogether.....but I'm not that smart!


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## KiwiMark (Aug 7, 2011)

benckie said:


> same thing, just with deans plugs (t connectors) just makes sure the batteries voltages are close


 
Yes, if the voltages aren't around the same then I treat them as separate batteries and charge them separately. I only charge matching sets as a group (either balance charging in series or parallel charging) everything else gets charged one cell or one battery at a time.

I do have a couple of 4 cell battery boxes that use 4 x 18650 in parallel as a power source to charge a cellphone - because these are 4 cells in parallel they will always have the same voltage, so they should be fine for charging in parallel too. I'm using 4 x 2500mAh cells which I'd probably charge at 1.2A, so if I charged the 4 cells in parallel at 4.8A then they should get ~1.2A each.

I now have my 208B charger (capable of charging at 20A) and my parallel charging board as mentioned. I can use my 106B+ and my 208B at the same time (powered from the same ATX PSU) and charge 2 different cells (or sets of cells) at the same time - this makes it easy to charge my 4 x 2500mAh cells for my cellphone charger while also charging the 14500 from my EDC light. A hobby charger may be good, but 2 hobby chargers is better!


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## DasFriek (Aug 8, 2011)

Maybe someone does know how to make a simple schematic from my plug so i can use it as a 7S set of leads all on its own. But if not the extension put me on the lead and idea of what i need. They show a 6S extension thats back-ordered so ill just find one somewhere else. The thing is i only need one plug as ill do it with magnets so its configurable as i need it to be.
I may pull the soft rubber backing off this board i have and look at the pin-outs and match them up to directions and pictures in the thread.
Thanks for the help.


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## KiwiMark (Aug 8, 2011)

DasFriek said:


> Do i need to use the board, Or can i cut the wires going into it and build my leads from that?


 
If any of this is wrong Lux will correct me (he knows his stuff)

There is no reason why you couldn't run off the that lead that plugs into your charger. Counting pin1 from the OPPOSITE end to the red wire I think it may works something like:
Pin 1 connects to the negative of cell 1 (same as main black wire), pin 2 to the +ve end of cell 1 (same as -ve of cell 2) pin 3 to the +ve of cell 2 (-ve of cell 3), etc.
I think you start from the pin furtherest from the red wire and stop once you are connected to the same place as the main red wire.

i.e.
3 cells:
pin 1 -ve of cell 1 (main black wire also connected here)
pin 2 -ve of cell 2
pin 3 -ve of cell 3
pin 4 +ve of cell 3 (main red wire also connected here)
other pins - not connected to anything (may need to insulate to ensure no contact)

Possibly something like a dab of paint on each wire (different colour for each wire) near the plug and another dab of the same colour near the end would help in keeping the wires in the right order.


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## DasFriek (Aug 8, 2011)

Whats good is the pcb seems to only be 2 layer - top and bottom, so i can see the traces of each wire. This will help verify what you stated also.
As for keeping track for now im using masking tape thats been numbered and ill label it all the way out to 7S since thats what the plug is capable of and wired for.
Ill test it on NiMH cells so i don't loose any fingers or houses during the process.


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## KiwiMark (Aug 8, 2011)

DasFriek said:


> Ill test it on NiMH cells so i don't loose any fingers or houses during the process.


 
Chances are that you will find there is no balance charge option for NiMH cells, it tends to be something that you only use on Li-ion cells. Just keep a close eye on the batteries, hit the > button to see the individual voltages and feel for signs of overheating (Li-ion cells shouldn't get hot while charging).


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## DasFriek (Aug 8, 2011)

Luckily my charger will charge everything i hook it too, It would charge my nipples if i ever get the urge. It does 1-16 NiMH cells at once. Its a Hyperion EOS 720i NET3 AD which is all run on software on my laptop. That is why im really wanting to get a Li-Ion setup done so i can take advantage of what the charger is made for except making graphs while testing cells. I highly recommend one if you have the extra cash to throw in the air, I don't know why i spent that much, But im glad i did.
It even has a temperature probe that shows the cells temps during cycles also.

Here is a graph of a cell from a new batch of 18350 IMR's i got from BIO.







Anyhow, It just so happened i have spools of red and black mono strand copper wire the same gauge as the adapters i bought for wiring up P60 drop-ins. So i didn't have to cut the adapter and the wires just slide right into the plug. But i think 7x 18650 cells is too much to count on charging at once, But its possible i may cycle all my 18350 IMR's a few times to break them in a bit as they do tend to gain capacity after a few discharges.

The wiring is a bit confusing until i pick a way im gonna attach the cells either in holders or in series with magnets with the latter sounding the easiest, But it takes up more room.


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## benckie (Aug 8, 2011)

jhn.holgate said:


> Mine is the same sort of thing - I'm going to keep my board intact because I have various LiPoly battery packs with the balancing leads already attached. But I've ordered some JST-XH extension leads - I figure I'll just cut the end off that I don't need and solder some ring terminals to suit my battery setup. You can get extension leads in 2-7s in packs of 10 for a few dollars from here: http://www.hobbyking.com/hobbyking/store/__9735__JST-XH_2S_Wire_Extension_20cm_10pcsbag.html
> 
> It can probably be wired up straight to the balancing plug in the charger, bypassing the board altogether.....but I'm not that smart!


 

they are a bit short once you get over 3s Ive been buying from here in 2s, 3s in 30cm (12 inch) and 45cm (18 inch) long approx

http://cgi.ebay.com/1-JST-JST-XH-2S...Control_Parts_Accessories&hash=item4cf84e5ee3




DasFriek said:


> Maybe someone does know how to make a simple schematic from my plug so i can use it as a 7S set of leads all on its own. But if not the extension put me on the lead and idea of what i need. They show a 6S extension thats back-ordered so ill just find one somewhere else. The thing is i only need one plug as ill do it with magnets so its configurable as i need it to be.
> I may pull the soft rubber backing off this board i have and look at the pin-outs and match them up to directions and pictures in the thread.
> Thanks for the help.


 
http://cgi.ebay.com/1-JST-JST-XH-6S...Control_Parts_Accessories&hash=item4cf84e69e6

the quickest way to work it out is, the red balance wire goes on the + of the first battery and the black wire goes on the - and you group the rest, meaning the red wire from the balance plug goes on the positive of the first battery, the wire next to it goes between the negative and positive on the second battery, the wire next to that goes between the negative and positive of the third battery, you keep working your way through till you run out and the last balance wire goes on the last battery.

then you attach the main charge leads to the two out side balance wires, so the red + main charge cable goes on the the red balance wire and the negative main charge cable goes onto the last balance wire.

this is only a 2s but its the same principle






i heat shrink the balance wires in pairs so its easy to know which ones witch.

the next one I'm making is 2 x 3s balance leads in series to make 6s with no main charge cables, but it will cost around 15 bucks to make, but it will be simple and save around 4 hours in charging.


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## DasFriek (Aug 8, 2011)

Wow, That explanation explained it very well! Plus the pic doesn't hurt either. Im still thinking of the best route for me to choose on layout of the cells.

And odd question, If we need to use the main positive and negative power leads, Why dont you need them with the adapter you linked above?
BTW thats a great link and i added to my watch list just in case of screw up's or i feel i need it. Thanks!


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## benckie (Aug 8, 2011)

you still need them, you just have to make your own, they are just the balance wires, you cut off one end and add magnets or a Charge cradle plus your main charge leads

on another note, in my description Ive used the balance wires as black, some are blue and some are white, but the first one will be red and the last one black, but it works the same way Ive described if that makes sense,

with your Hyperion charger, leave the balance board on it as is and just buy separate balance leads you can pick any combination from 2s to 7s jst-xh leads then add your main charge cables to it, by soler or alligator clips, its the same principle of the pictures Ive posted, just my balance board is in built into the charger and yours is on the out side, then leads Ive made would plug into your balance board on your charger as they are the most common jst-xh type

the next one I'm making just waiting on the magnets will not have main charge cables to the balance wires due to they will be on a PCB and the balance wires will be the charge cables as well as balance leads, the same as attaching the main charge cables to the first and last balance wire, once its been tested ill post up pictures and link,s it should neaten up the process.


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## DasFriek (Aug 8, 2011)

Id really like to see pics of what your making when done, The previous work has been great and encouraged me to get off my duff and do mine like i planned on when i bought it many months ago.
The only issue about keeping the board and buying separate output cell leads is buying all the magnets and pretty much hooking them up the same way. But if i use extensions i just dont use the extra leads. So it kinda expensive to buy 6 different plug adapters and 50 magnets.

I also have green wire along with the black and red so maybe it could be helpful in remembering a hook-up sequence.
After looking at your pic above again this is pretty darn simple if you lay the cells out in a series configuration just to get used to how its done, And later if i want a more compact system ill know how the wiring goes. Using cradles and wiring that would be confusing a bit until i get the hang of it.


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## benckie (Aug 8, 2011)

what I'm making is nothing special I'm going to use a 2 x 3s to 6s series adapter it was under 3 bucks from hobby king, i could not make one that cheap, its nothing flash just some thing cheap, easy with the xt60 plug cut off two 4mm bullet connectors added with a bit of heat shrink, then 2 x 3s balance leads with some heat shrink added to keep the balance wires in pairs with 8 cheap magnets from ebay.

i would like to use charge cradles to, easy to work out it takes a bit longer just pushes the price up a a little and just as messy but more compact, some thing like these would be good if you didn't want to make your own.

http://www.luminousdiy.com/Light%20Kits%20and%20Parts.htm#holders


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## DasFriek (Aug 8, 2011)

Well i have everything built and soldered as i already had the parts on hand as i just have been putting off making this until i learned more about the hobby and Li-Ion cells.
I think i may order one of those holders as by the time you buy small parts here and there you get the same end result but usually its not gonna look half as good as that cradle does, At least for my work anyhow.
Im gonna start with 2 NiMH AA cells that are cheapish and see how the software on my laptop responds since i control 100% of the charger threw software. After that i have many Li-Ion cells i want to cycle as capacity does go up until about the 5th cycle ive found on good cells from Sanyo and Panasonic.

If i dont respond back it means im fighting a fire and ill be online later from the library as im sure to be evicted also. lol


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## LuxLuthor (Aug 8, 2011)

Most have already answered, but you can keep the same 8 pin JST-XH connector that interfaces with your charger and say you want to charge 4s, then either ignore the extra 3 wires (stock is anticipating a need for 7s), or you can easily use a safety pin and press down on the protruding metal flange and the wire and it's plug will just slide out.

In this example, I think that is a 5s JST-XT holder with 2 empty slots since I only need 3 wires for balance charging 2 cells. 







They are giving you the set of plugs anticipating that you are using premade packs that have their own JST plugs that fit onto the adapter board...but you could buy a bunch of 8 pin JST-XH connectors and pins and crimpers and make your own leads.


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## benckie (Aug 8, 2011)

i don't use the computer logveiw function of my charger I'm to lazy, but don't stress to much about fire, the flames from lipo,s only reach about 5 foot tall and about 1 wide and make pretty blue, green and yellow sparks with nasty smoke, i guess a li-ions are the same ? one of my dinning room table legs is black from a lipo years ago, long story that one.

good to see your using good cells the grey ultrafires i have pictured are not worth a pinch of kangaroo Pooh so they are the experimental cells, I'm yet to set fire to a li-ion cell, but ive melted a few leads with them and made some good sparks :huh: with parallel all in the name to save time in charging.

they seam pretty forgiving more so then lipo,s when i used to make series charge leads for balance charging multiple 11.1v 3s (3s1p) battery packs years and years ago it was easy to set them off if you didn't connect them in the right sequence.

these li-ions have been used for years in laptops and cordless power tools so they are not to bad IMO but a double check before connecting multiples together will never hurt, when i first make a charge lead for any thing i always test it on a concrete floor in the middle of my shed just in case.

I'm going to buy a back to back 6 x 18650 battery holder from the place i linked and have a go at making a pretty looking charge cradle that does not need 3 foot of space and i might even splash out and buy some decent 18650,s one day, the trust fire flames i have been using seam OK and take near on claimed mah, i was looking at some aw,s but at $18 each plus shipping :sick2:

any way let us know how you go


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## DasFriek (Aug 8, 2011)

Boy has this been a journey, But it seems right so im gonna go with it.

First attempt i hooked it up exactly as i was told above:

pin 1 -ve of cell 1 (main black wire also connected here)
pin 2 -ve of cell 2
pin 3 -ve of cell 3
pin 4 +ve of cell 3 (main red wire also connected here)

I just used 2 cells and NiMH and things were really screwy with the software, It read cell #1 at 1.3v and cell #7 at 2.6v
Of course the charger isnt gonna do anything with readings like that. So i started moving leads around as cell #7 was the issue, And that was the cell the red wire was connected to the final positive tab of the cells.
I took the red wire off and put lead #3 on there and hooked it up and it now read cell #1 @ 1.3v and cell #2 at 1.31v and was reading cell gap and performing like it should.
What i found also is the balance leads will read the cells and tell me if everything is hooked up correctly BEFORE i ever have to put the main power leads on.
Why my charger has to be different i have no clue, But it is.
This also explains why when i looked at the PCB board for all the differant cell count connecters plug into and it showed lead #9 (The red one) only being used with 7 cells. And the rest were wired is succession of 1,2,3,4,5(empty),6,7,8,9 (red).

So i guess from now on i start at the first negative with pin 1 and use them in order and red only gets used when i hit 7 cells.
I appreciate all the help guys as without it i would have had a clue on how to even attempt this, Let alone make an adjustment for this odd hookup.

Have a look for yourselves, She's runnin great!


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## DasFriek (Aug 8, 2011)

BTW on cells, I think its easier for people in the USA to get the decent cells at better prices than some people. But i try and buy a few good ones when i have spare cash and after a while i have a decent selection of high end cells.
But my first cell purchase was off ebay and i bought 4 Trustfire Flame 18650's unprotected at that and they turned out to be fakes that were relabeled as once i tested them on this charger they wouldn't hold over 200mAH capacity.
After that i swore to only buy Sanyo or Panasonic and Samsung cells, Oh and a few IMR's also. But ive been lucky as ive found a hook-up for Sanyo unprotected 2400mAH cells at $2.40 each shipped. And the IMR's from BIO are awesome except the 10440 IMR's are horrible.


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## DasFriek (Aug 8, 2011)

Everything ran well for the few hours while i slept cycling the 2x AA NiMH cells with balancing and peak what ever it is.
So now i went the same way in hooking up 2 IMR 18650's i just got in the mail and will run 3 cycles on them at .7/.7 charge and discharge.
As you can see everything is reading like it should and wouldn't be that way if it was hooked up incorrectly, Despite my attempts to hook it up like it should be according to the thread. So i guess it could be a cautionary tale to others coming to learn how to hook their chargers up that not everything is as it should be all the time.

Im really disliking these magnets setup as i put the cells on a ceramic saucer for fire safety reasons, But they want to move out of shape and i feel the magnets are adding some resistance as its reading high for IMR cells. i have a steel guide rail most cells will rest in perfectly, But being steel it will be a pita keeping the magnets on the cells and not the guide rail. So im really considering the flat pack from luminousdiy.


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## KiwiMark (Aug 8, 2011)

DasFriek said:


> Im really disliking these magnets setup as i put the cells on a ceramic saucer for fire safety reasons, But they want to move out of shape


 
A ceramic saucer probably isn't the easiest surface to sit the cells on - I picked up a couple of ceramic floor tiles that I find work really well. They were cheap (a dollar or 2) and they are a good size, about 330mm square I think.


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## DasFriek (Aug 8, 2011)

I definitely agree, Its the worst thing possible. But its fire proof and im limited on space as im doing my work on my end table next to my recliner. It was fine for single cell work which was all i was doing previously.
Im working on my "Rail system" and ill post pics tonight, Its made from an adjustable sliding mount for sockets on ratchet sets. Now im insulating it since its steel and then i need to add lateral feet to stop roll over, But its perfect for sitting cells into.
But i wouldn't hurt to sit it on a tile you you suggest as the rail is thin and not much protection underneath it.


(Edit) I got the charging rail done tonight and fully insulated since its made of steel and i don't want no accidental shorts if a lead falls off a magnet. Sadly its almost unrecognizable compared to what i started with and i took no build pics as i never do, I cant take pics as my projects always change 10 times during the building process. Im waiting on 2 IMR cells to discharge and ill take pics of it all. Ill also hunt down a pic of the socket holders i used.
Here is a pic of the holders, But i used just the bare rails and put them back too back and removed the clips except to make feet on the ends with.
http://img.photobucket.com/albums/v447/deathstar13/socketholder.jpg


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## benckie (Aug 9, 2011)

glad your moving in the right dirrection and things are working out for you


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## DasFriek (Aug 9, 2011)

Here is a few pics of my setup.
I wished i could have taken pics in the building process of the insulated rail, But i have a hard time doing that as my directions always change many times until i pick a final route and that would take way to many pics to make it a pita to get the work done. But basically its just 2 of the socket holder rails with the snap-on sliders removed and the rails crimped back to back using 4 of the snap-on sliders for a socket. I also added some 20mm O-rings that hold the cells in place and work great and keeping the temperature probe tight against the cell.

You will see in in the pics with the 18650 cells i had the red wire correlated to the red wire in the harness, But i switched that so i know that its the first wire to go on the first negative end in the series. The pics with the IMR 18350 shows the new wire arrangement. The charger itself is magic in how it adjusts for cell gaps while charging or discharging. It will even run until i stop it and it will keep a constant balancing job once charging is done as long as the stop button isnt hit. But it wont go over 4.201v no matter what.

Thanks for everyones help as this makes break-in cycling so much easier and 10x faster and now i get the full use of the charger i always intended to do, But didnt know how to wire it. Thanks!


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## My2Cents (Aug 9, 2011)

DasFriek, from what I understand, there is no such thing as "break-in" cycles for LIxx chemistry. It will actually hurt because battery loose capacity for every cycle. No way around it.


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## rmteo (Aug 9, 2011)

Also, since you are charging loose cells, there is no need (or advantage) to balance charge them in series - just charge them in parallel. Here's how I charge 1-8 cells at the same time.


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## KiwiMark (Aug 9, 2011)

rmteo said:


> Also, since you are charging loose cells, there is no need (or advantage) to balance charge them in series - just charge them in parallel. Here's how I charge 1-8 cells at the same time.


 
There is one obvious disadvantage to charging in parallel - you have absolutely no way of knowing how much capacity is going in each cell. If they are all the same model/age cell that are drained together you could GUESS that they will each take about the same as each other, but if one cell is failing you wont be able to tell when charging.
Balance charging enables you to get data on each cell - you can even graph it to see how each cell compares to the rest.

I'm not saying that parallel charging wont work just fine, just pointing out a drawback.


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## benckie (Aug 10, 2011)

thats not correct and only should be used if all batteries have the same voltage befor charging


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## SilverFox (Aug 10, 2011)

Hello Benckie,



benckie said:


> thats not correct and only should be used if all batteries have the same voltage befor charging


 
What is not correct?

Tom


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## Mr Happy (Aug 10, 2011)

My2Cents said:


> DasFriek, from what I understand, there is no such thing as "break-in" cycles for LIxx chemistry. It will actually hurt because battery loose capacity for every cycle. No way around it.


Not necessarily. Some lithium ion cells show improved internal resistance after a few cycles from new. There can therefore be an advantage to "breaking in" lithium ion cells to get the best performance out of them.


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## 45/70 (Aug 10, 2011)

Mr Happy said:


> Not necessarily. Some lithium ion cells show improved internal resistance after a few cycles from new. There can therefore be an advantage to "breaking in" lithium ion cells to get the best performance out of them.



Hi Mr H. I've seen this suggested from time to time, however I've never seen where any manufacturer recommends a "break-in" for Li-Ion cells. Maybe this applies to the newer high cap cells with the nickel safety layer?

In my experience with LiCo, LiFe, and LiMn cells, Ive never seen any _significant_ improvement after cycling. I've always thought this suggestion was just a leftover from the NiCd/NiMh days, or possibly due to the tester's (myself included) cells being warmed up during the testing, or perhaps even the runtime in a light increasing due to the Vf of a new LED light lowering, due to the breaking in of the LED itself.

In any case, I seriously doubt that fully discharging and recharging, such as is the practice for breaking in NiCd/NiMh cells, is necessary. Normal use, eg. discharging to 50% and recharging, should suffice to "break in" Li-Ion cells, if it is even necessary.

If you have any links referring to this "breaking in" of Li-Ion cells, I'd appreciate it. As I said, I'm not familiar with the newer cells, such as the Panasonic "NNP" cells. There may very well be a different regimen for these.

Dave


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## KiwiMark (Aug 10, 2011)

45/70 said:


> In my experience with LiCo, LiFe, and LiMn cells, Ive never seen any _significant_ improvement after cycling.


 
I have received new Li-ion cells, charged them, drained them (noting capacity received from them) and then charged them again - this is something I often do so that I know what the capacity of the cell is. I have tried a 2nd discharge occasionally - every time I have tried that I get about the same capacity as from the first discharge, no significant improvement. This would seem to match your experience which makes me think that you are correct.

I have heard of letting a laptop or phone or other 'smart' device run flat and then fully charging it so that the battery management software can get some better data to calculate remaining run-time from - but I doubt that this gives any improvement in actual run-time achieved.


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## 45/70 (Aug 10, 2011)

Hi Mark. Well that makes two of us anyway. As I said though, some of the newer Li-Ion cells may actually be different.

I meant to respond earlier to your previous post.



KiwiMark said:


> There is one obvious disadvantage to charging in parallel - you have absolutely no way of knowing how much capacity is going in each cell.



While I agree with you that a balance charge is probably better, when parallel charging you can usually tell if there is a "bad" cell by checking the cell's voltages after letting them sit for a while after charging. If a cell's voltage has dropped significantly, compared to the other cells that were charged in parallel with it, this is a sure sign of an under performing cell.

Dave


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## Mr Happy (Aug 10, 2011)

In response to Mark and Dave:

I have read that while the capacity might not improve, the voltage under load/internal resistance might improve. Also I don't mean break-in in the C9000 sense, just normal usage with a few charge/discharge cycles.

Here is one reference I came across recently, relating to this:

http://www.youtube.com/watch?v=2rUoKBrUPnA#t=04m00s

Of course this might be bullshit on the part of the cell vendor, but it's not the only place I've come across the idea of breaking in lithium ion cells. I don't know the outcome of the particular story in the video.


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## benckie (Aug 11, 2011)

SilverFox said:


> Hello Benckie,
> 
> 
> 
> ...


 
i stole this from another site from another person as i cant be stuffed 



okwchin said:


> Im a fan of series charging for this reason, because of the increased convenience, and no need to worry about differences in charge levels. Even the slightest voltage difference means large charge capacity differences, and connecting these cells together is effectively shorting the cells until the capacity differential is conducted, limited by the internal resistance of the battery.
> 
> As a Theoretical example, this gives an idea of the kind of current involved. If there is a voltage difference of about 0.5v, given a total internal resistance of 0.05 ohms, then the instantaneous current flow will be (V/R) = 0.5/0.1 = 5 Amps. So the instant you connect cells in parallel with a voltage difference of 0.5V, you will be discharging one cell at 5A, and charging the other at 5A for a short period.
> 
> ...


 
there is a reason why all the hobby li-xx rc battery packs are normaly in series and balance charging is used, just my thoughts do what works for you.


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## Lightfoot98 (Aug 11, 2011)

As to what okwchin says,

I've checked the inrush current of cells that were 0.5V different, and only had about 230-250ma current.
It quickly tapers down to lesss than 50ma in a few minutes.

Some a little more, some a little less.

I'm comfortable with paralleling cells with up to 0.4v difference going onto the charger for parallel charging.


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## Lightfoot98 (Aug 11, 2011)

KiwiMark said:


> There is one obvious disadvantage to charging in parallel - you have absolutely no way of knowing how much capacity is going in each cell....


 
The cell will only accept what it needs.

My example with the lights...

Plug a 40watt, a 60watt, a 200watt, and a 10 watt lightbulb into the same electrical outlet, it will only take what is needed.

The voltage will rise according to the highest capacity cell, and the other cells are just along for the ride.

A 1000mah cell and a 3000mah cell charged in parallel will be just fine. The larger capacity cell will take more, the lower capacity cell will take less.
The charger is only supplying the current at a specified voltage.
Both cells will complete the charge at the same time at the same ending voltage.


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## rmteo (Aug 11, 2011)

benckie said:


> ...there is a reason why all the hobby li-xx rc battery packs are normaly in series and balance charging is used, just my thoughts do what works for you.


The reason why hobby packs are charged in series (with balancing) is because the packs cannot be disassembled for parallel charging unlike loose cells used with flashlights. Take a look at a typical 3S2P pack. *ONLY* the 3S is section is series balanced charged (note the 4-lead balance connector). See here http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7655


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## 45/70 (Aug 11, 2011)

Lightfoot98 said:


> As to what okwchin says,
> 
> I've checked the inrush current of cells that were 0.5V different, and only had about 230-250ma current.
> It quickly tapers down to lesss than 50ma in a few minutes.
> ...



We're getting OT here, as this thread is about series charging with balancing. Just the same, I thought I'd link to a thread by SilverFox where he explains some testing he did parallel charging Li-Ion cells. The conclusion from his testing was, that as long as the cell voltage of the cells being parallel charged is within 0.5 Volts, there is no problem.

I myself prefer that the maximum voltage difference between the lowest cell voltage and the highest be no more than 0.1 Volt. This way the higher voltage cell, or cells, are not being discharged any more than if the cells were charged in series with the typical "on board" balancing feature, that most hobby chargers offer.

Also, note that taking the maximum 0.5 Volt figure, if you think about it, there are not too many situations where you might be charging cells with this much difference in voltage. You would pretty much have to be charging fully discharged cells along with fully charged cells to run into trouble parallel charging.

Dave


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## SilverFox (Aug 11, 2011)

Hello Benckie,

The theory is sound as far as it goes...

The problem is that it is looking at an instant of time and can not be substantiated by actual measurements. As soon as the two cells are connected there is a surge of current, but Li-Ion cells are fully capable of handling surges without damaging the cells. Surge performance is different than constant current performance. When cells are connected in parallel the voltage of the higher voltage cell drops and the voltage of the lower voltage cell increases. 

A cell that is discharged to 3.0 volts should rebound to 3.6 to 3.7 volts once the load is removed. This means that if you happen to parallel a fully charged cell with a fully discharged cell the voltage difference is only 0.6 volts initially. If you are discharging the cells before charging them in parallel, the voltage difference ends up being quite small.

When charging multiple cells it is important to keep the cells in balance. You can do this by charging in series and using balancing taps or by parallel charging.

Tom


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## rmteo (Aug 11, 2011)

Not saying that anyone should try it but I have connected a fully-charged and a discharged 18650 in parallel (one several occasions and subsequently parallel charged them with a hobby charger) and there is absolutely no drama whatsoever.

In fact, you would be hard pressed to tell which cell is which when they are connected. You can tell them apart only by disconnecting them and measuring with a DVM. The discharged one will be at a lower voltage.


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## 45/70 (Aug 11, 2011)

That seems to go along with what Tom found in the post I linked to above, rmteo.

The reason I prefer to have the cell voltages much closer is that the discharging of the higher voltage cell, or cells that takes place is cumulative. For example, If you pair two cells together that are 10% different in capacity, after 10 charges this works out to the same as if you had actually used the cell one discharge cycle, but you didn't get any use out of it!

The same applies when charging cells in series with balancing, as well. Unfortunately, as far as I know, all balancing chargers, as well as separate balancing units, _discharge_ the higher voltage cells, rather than charge the lower voltage cells, to balance the "pack". So, whichever way you charge cells, it's best if the voltages are close, as if it isn't, you're just adding that much more wear to the cells when charging. It's a minor amount, I know, but......

Dave


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## rmteo (Aug 11, 2011)

On a personal level, I have no cause to charge more than one cell at a time as I do not have/use multi-cell lights, so loss of capacity is a non-issue for me. However, for someone who has something like a TK35 it probably won't matter much either as each pair of cells are going to be close (in voltage) prior to charging.

I think that parallel charging is the simplest, safest and most fool-proof method (assuming you have a hobby charger - which is also needed for balanced series charging). The reason I did those tests was to ensure that charging multiple *same* *type *cells in parallel can be safe even if you (accidentally) have charged and discharged cells in the group.

One other caveat - this was done using unprotected (16340 and 168650) cells (I do not have/use protected cells) and may not be the same with protected cells.


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## KiwiMark (Aug 11, 2011)

Lightfoot98 said:


> The cell will only accept what it needs.


 
Yes, parallel charging should work fine. But what I was saying is that you don't KNOW how much capacity is going into each cell. When I charge a single cell the charge finishes with a mAh reading for how much capacity the charger put into the cell - I could take a note of that and see how the cells capacity holding changes over time. Some hobby chargers are able to provide a graph through a computer for each cell while balance charging. When parallel charging several cells you just don't have that information available - the charger has no idea of how much of the power it is pumping out is going to each cell. As far as the hobby charger is concerned it is just charging one big cell.

So it all comes down to whether you just want to get your batteries charged or whether you want the info on each cell.


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## benckie (Aug 12, 2011)

we got back to the start and what most have been saying if the cells are close in voltage parrallel charge i think i said that atlest once, test each cell and go through them all to find the ones that have close voltage and charge them in parrallel, or just put them all together and series ballance charge, i have 3 multible cell torches that run in series and after hard running the cells are always a little bit to far out for my liking for parrallel and my expernice from lipo,s makes me like series.

*but people do what ever floats your boat*


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## Lightfoot98 (Aug 12, 2011)

benckie said:


> *but people do what ever floats your boat*[/B]


 

Don't worry, we do.


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## benckie (Aug 12, 2011)

this thread is like the Aussie ford and holden, gm or ford, Chevy or doge trucks each person will pick out what they like for there reasons or regurgitate what they have seen else where.

if you want the best dam way to charge batteries its one by one with a 0.25 c charge at you are looking at 50+ hours constant charging for 10 batteries or 10 days if you do one a night

there is a reason why some of use like to series charge and go the extra mile and balance series charge and remember this thread is about balance charging cradles


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## 45/70 (Aug 12, 2011)

benckie said:


> ......what most have been saying if the cells are close in voltage parrallel charge i think i said that atlest once, test each cell and go through them all to find the ones that have close voltage and charge them in parrallel, or just put them all together and series ballance charge



Actually, it's the other way around. If the cells are very far off from each other, you would do better to parallel charge them. Most hobby chargers with an "onboard" balancing feature are quite limited as to their balancing capability. If you use a separate balancing unit, along with your charger, then it's not so much of a problem.

Dave


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## KiwiMark (Aug 12, 2011)

45/70 said:


> Actually, it's the other way around. If the cells are very far off from each other, you would do better to parallel charge them.


 
If the cells are very far off from each other then I would always charge them individually. I would never recommend charging cells as a group (parallel or series) if they aren't close to each other in voltage at least.
The main reason I have 2 hobby chargers is so that I can charge 2 cells completely independently at the same time, it also allows me to charge 2 groups at the same time - I could balance charge one group on 1 hobby charger and parallel charge another group on the other charger. I can charge 14 cells at once if I need to.

If they are a matched set used together then it should be fine parallel or balance charging them. Parallel charging will mean that you CAN'T get a graph of what goes into each individual cell (as I've mentioned) but they should charge just fine, I'd suggest checking each with your multimeter to ensure close voltages before connecting them in parallel.


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## 45/70 (Aug 12, 2011)

KiwiMark said:


> ......I'd suggest checking each with your multimeter to ensure close voltages before connecting them in parallel.



eg. within 0.5 Volts. Did anyone actually read Tom's post I linked to in post #73?

Dave


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## LuxLuthor (Aug 12, 2011)

45/70 said:


> Actually, it's the other way around. If the cells are very far off from each other, you would do better to parallel charge them. Most hobby chargers with an "onboard" balancing feature are quite limited as to their balancing capability. If you use a separate balancing unit, along with your charger, then it's not so much of a problem.
> 
> Dave


 
Dave, I do not remember ever having read anything myself specifically about this topic to give an authoritative answer, and if you have a reliable resource it would be interesting to read why that makes sense. I'm not afraid of parallel charging, or even just balancing cells with each other separate from charging, but wanted them relatively close before starting (something like within *0.05 to 0.075V (corrected decimal place typo) *apart). That's why I made this set of 6 cell magnet parallel leads that can be used for charging or balancing.




​It didn't make "common sense" when I thought about a simple scenario (admittedly using unlikely extremes to exaggerate my question) where you had two Lithium *Cobalt *Ion cells that have voltages of say 3.10V and 4.15V. 

Connecting them in parallel with a high conducting (low resistance) metal across the terminals is going to result in a high current, rapid discharge from the 4.15V into the 3.10V cell. You would need an oscilloscope to see the initial current spike which may get quite high. It seems that this may also trip the 5 to 6 amp output protection circuit, but doesn't seem to be a good policy for either cell.


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## LuxLuthor (Aug 12, 2011)

45/70 said:


> eg. within 0.5 Volts. Did anyone actually read Tom's post I linked to in post #73?
> 
> Dave


 
I started my last post, and then went to take that photo and got distracted, and did not see your cross post in the meantime. I had not read your earlier post, or the link to Tom's thread, so thanks for pointing that out again. 

While Tom's test has some rigor, I can see a number of issues in part because it is now 4-5 years old. He did not use cells with PCB circuits that have current limits. He did not use an oscilloscope scanning with a high enough frequency to pick up how high the initial current spike went, and I don't regard his $30 Craftsman 82062 DC Clamp Meter as an adequate testing device...so I would take his observations in that instance with a huge grain of salt.

In any case, your previous post contrasting with *benckie* did not _*necessarily *_imply you were talking about voltages within 0.5 Volts, which I *do not* consider being close to each other. I'm not really sure what you meant by saying "_*If the cells are very far off from each other, you would do better to parallel charge them.*_" but I don't agree with leaving that impression out there regarding parallel charging. 

My general guideline, similar to Kiwi-Mark is that before Li-Ion cells are put in parallel with each other, their voltages should be tested and be within* 0.05 to 0.075V *of each other.

_*Edit: Corrected the decimal place, and tried to fix previous paragraph in red to what I meant. Sorry for the confusion. *_


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## 45/70 (Aug 12, 2011)

LuxLuthor said:


> My general guideline, similar to Kiwi-Mark is that before Li-Ion cells are put in parallel with each other, their voltages should be tested and be within 0.5 to 0.75V of each other.



Lux, I'm not sure what your definition of "close in voltage" is, but if you take a LiCo Li-Ion cell that is at 3.7 Volts, or about 15% remaining capacity, and another that is 4.20 Volts, or fully charged, I would call that a fairly wide difference in voltage, yet it is 0.5 Volts. I'd also say that if you have LiCo cells that are 0.75 Volts apart, the lower voltage cell, or cells, are over discharged, or at maximum 3.45 volts.

My next question would be, how often do you charge cells, at the same time, whether in parallel, or in series with balancing, that are basically discharged, along with cells that are fully charged? My point being that this really isn't very likely to happen.

All that said, and I've said this before, I like to have my cells within 0.1 Volt when I parallel charge them. Usually, the cells I charge in parallel are "sets" that are reasonably well matched and are actually closer than 0.1 Volt. And yes, a means of measuring the voltage of your cells is mandatory, when dealing with Li-Ion cells, whether charging, using, or storing, you _must_ monitor the voltage of Li-Ion cells.

Dave


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## KiwiMark (Aug 13, 2011)

45/70 said:


> Usually, the cells I charge in parallel are "sets" that are reasonably well matched and are actually closer than 0.1 Volt.


 
This is also how I do it - I charge a set of cells which would typically be more than 1 cell that were bought together and have since been charged the same as each other and put into one device and drained together in series. Often when I remove those cells to charge them they are within 0.05V of each other, definitely nowhere near 0.5V apart.

I have 8 x IMR 16850 in one light, 5 x IMR 26500 in one light, 3 x 32600 in one light, 2 x 32650 in each of 4 lights, 2 x LiFePO4 16350 cells in my A2 and some other multi cell setups. I treat these as sets of cells and they are all the same age/brand/model of cells. If I get a crook cell then I'd buy a full new set and use the remaining good cells in another device, keeping complete sets together.
There really isn't any reason for any of the cells I use in sets to ever be very far apart in voltage or capacity remaining. I should be able to safely charge any set of cells I have in parallel or balance charge in series.

When I pull a 16340 or 14500 or 18650 or 10440 cell from a single cell light I always connect it up to a hobby charger and charge it by itself. I'm not going to pull the 10440 from my LF2XT and the 14500 from my D10 and charge them both up together in parallel, different batteries used separately always get charged separately - that's the way I've always done it and I have no intention of changing that.


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## LuxLuthor (Aug 13, 2011)

Dave, I screwed up a decimal place, and fixed the above posts. Sorry. My personal parallel connection guideline is a bit more conservative than Kiwi-Mark's of 0.1V as I meant to state it as the 0.05 to 0.75V difference.

I still question the basic general idea that "If the cells are very far off from each other, you would do better to parallel charge them." -- for the reasons I stated earlier. I made the mistake of reading your subsequent post as 0.05V and do regard 0.5V as too "far apart" for parallel charging. If you said that based on Tom's earlier study, then I still question that for the reasons stated earlier.


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## 45/70 (Aug 13, 2011)

Lux, I think your 0.050-0.075 Volt limit is fine, you really can't be too careful, however I think it's being a bit more cautious than necessary.

In Tom's test, his setup had a voltage difference of over 2.00 Volts, not the final recommended maximum of 0.50 Volt. Regardless of the accuracy of the clamp ammeter, the general characteristics of what happened when the cells were paralleled, still applies. The duration of the peak high current, whatever the actual value, was very brief. And, as he mentioned, LiCo cells are comfortable with surges as high as 10C and I really don't see an amperage that high occurring, if the 0.50 Volt differential rule were followed. As for cells with protection circuits, I would think that the surge is so short, that most would not trip and would survive the half second, or so spike. I could be wrong here, as I've certainly never tried it.

Again, I really don't see anyone purposely charging cells that are basically discharged, along with fully charged cells, which is about what you would have to do to get a 0.50 volt difference between cells. That said, I would definitely consider 0.50 Volt as a _maximum_ differential, and a value to best be avoided.

My comment "If the cells are very far off from each other, you would do better to parallel charge them" was considering the fact that the most common hobby chargers used here on the Forum have a maximum discharge current of 100-300mA during balancing. Considering this, parallel charging would be much more suitable for cells that were "very far off" in voltage, as the charger would be limited to a 100-300mAh correction per hour, whereas parallel charging would yield much faster results.

Another point I would like to bring up, is that many here on the Forums believe that because hobby chargers are designed to charge NiCd/NiMh and Li-Ion cells in series, that this is the best way to charge cells. This is not necessarily true. The primary reason hobby chargers are designed to charge cells in series is because in the R/C hobby, cells are usually welded or soldered into "packs". In this situation there is no choice as to how to charge the cells, you can either charge them in series, or charge them in series, and that's it. In our hobby, where we most often use "loose", or individual cells, other means of charging, such as separately, in an independent channel charger, or in parallel for Li-ion cells, often is the better option.

Dave


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## LuxLuthor (Aug 13, 2011)

Dave, thanks for being magnanimous in your posts, given my stupid typo/error! I always enjoy reading your posts, and have learned a lot from you.

I know you (like Tom) have a far above average understandings of proper battery use, and would not do anything unwise. I was more wanting to put reasonable limits on the idea that the farther your Li-Ion cell voltage are from each other, the better it is to parallel charge--which you have subsequently done. You and I have both read too many posts from new or inexperienced users who do not *yet *know about unique properties of Lithium primary/secondary cells, resulting in their trying to (or asking about) charging Lithium primary, mixing chemistries, not having a DMM, etc.

Thanks for your expertise and contributions!


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## SilverFox (Aug 13, 2011)

Hello LuxLuthor,

I am shocked that you question the "precision" of my camp meter...  

If we look at the theoretical values we come up with a maximum of 18 amps during the initial surge. The 18650 cell had a capacity of 1600 mAh, so it would experience a momentary surge of 11.25C. Most high quality Li-Ion cells are capable of handling a 10C surge without problems, and reality often falls a little short of theoretical expectations, so I still don't have a problem with a momentary surge involved.

The 26500 3200 mAh cell at 18 amps is only seeing a 5.6C theoretical surge.

It would be interesting to see if the protection circuit used on protected cells trip or are able to take this type of surge in stride. It would also be interesting to see if the actual surge current could be more accurately measured.

When using Li-Ion cells in series, the cells need to be well balanced and a 0.05 volt difference would be the maximum difference between cells, but when hooking cells in parallel for charging the difference in voltage can be higher.

Tom


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## LuxLuthor (Aug 13, 2011)

SilverFox said:


> Hello LuxLuthor,
> 
> I am shocked that you question the "precision" of my *camp *meter...



LOL! Well maybe if you had stepped up to "Radio-Shack Quality" for your 'campy' clamp meter!!! Although "*Radio-Shack Quality*" may be the modern example of an oxymoron, since "military intelligence" is getting stale.



SilverFox said:


> If we look at the theoretical values we come up with a maximum of 18 amps during the initial surge. The 18650 cell had a capacity of 1600 mAh, so it would experience a momentary surge of 11.25C. Most high quality Li-Ion cells are capable of handling a 10C surge without problems, and reality often falls a little short of theoretical expectations, so I still don't have a problem with a momentary surge involved.
> 
> The 26500 3200 mAh cell at 18 amps is only seeing a 5.6C theoretical surge.
> 
> ...



Yeah, it is more a question of the PCB limits and the oscilloscope confirmed duration, current amount, and condition of the "puppies" (Panasonic vs. Acme) being tested.

Then there's the general safe guideline of what "higher" should be limited to for parallel charging cell differences, under almost all reasonable circumstances. 

One man's sensible "higher" may be 0.1V; another man knowing little about Lithium Cobalt may think a 1.75V difference is just fine (to intentionally exaggerate the point).


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## HKJ (Aug 14, 2011)

I also want to check the current between two parallel batteries:





I used the above setup connected to my scope.

First test with two older cells:





A closer look at the initial spike:





Only about 2 ampere, that was not very much, how about using some new quality batteries:





And again a look at the initial spike:





A maximum of 6 ampere.

Note: My equipment can easily show 1 ms spikes.


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## SilverFox (Aug 14, 2011)

Hello HKJ,

Thanks for checking on that.

Another thing to keep in mind is that we are talking about charging cells that have been discharged. The worse case is to parallel a fully charged cell with a fully discharged cell. 

When we move to the other end of the spectrum we vary easily could find ourselves in the situation where we are paralleling a cell with a voltage of 3.1 volts to a cell with 3.6 volts. Here we have the same 0.5 volt difference, but both cells have about zero capacity to support a current surge.

Tom


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## 45/70 (Aug 14, 2011)

HKJ, nice job, as usual!:thumbsup: Very interesting results. I might also point out that the differential voltage here was more than 0.50 Volt in both cases, adding support for this being a safe recommended maximum value, IMO. Just the same, closer is always better.

Lux, thanks for the kind words. I needed that, not so much as pertains to CPF, but just in general. It seems we both are keeping an eye out for the newcomers, and attempt at least, to prevent them from running into problems.

Dave


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## LuxLuthor (Aug 14, 2011)

HKJ,

That was some superb work, and exactly what I would have wanted to see on many aspects. 

*1) You demonstrated and captured the ms spike by testing with your oscilloscope 

2) You used more up to date AW cells which also answers the question of how this would work with a current spike going through a cell PCB in this scenario. One question was not knowing what amount and duration of a current spike AW has his chips set at before interrupting the circuit. The other was how "hearty" are his PCB components when subjected to higher spikes.

3) You used extreme differences of voltage, in the second case a full 1.0 Volt difference (which is way beyond what someone would run into on a practical basis), which gives a wide margin of safety factor to protect the 'dunderheads.'

4) It appears you used somewhat thicker wire to not have that become a significant resistance barrier to a current spike.
*​If this was repeated a couple more times by others, it would make a strong case that it is safe to connect Lithium Cobalt Ion cells in parallel (for equalizing or charging) with little regard for even knowing the DMM voltages, but in any case could be moved from 45/70's 0.5 up to 1.0 V differences.

Superb work that is an invaluable resource on this subject. (? Put in threads of interest, with link starting at his post ?). :bow:



SilverFox said:


> Another thing to keep in mind is that we are talking about charging cells that have been discharged. The worse case is to parallel a fully charged cell with a fully discharged cell.



And you know someone who doesn't have a DMM will do that. 



45/70 said:


> HKJ, nice job, as usual!:thumbsup: Very interesting results. I might also point out that the differential voltage here was more than 0.50 Volt in both cases, adding support for this being a safe recommended maximum value, IMO. Just the same, closer is always better.
> 
> Lux, thanks for the kind words. I needed that, not so much as pertains to CPF, but just in general. It seems we both are keeping an eye out for the newcomers, and attempt at least, to prevent them from running into problems.
> 
> Dave



Dave, :bow:


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## benckie (Aug 15, 2011)

very nice work HJK

2 amp spike is not much at all for discharge, but charge it might be but ive never used those cells.

6 amp to me might be a bit much, over time it will increase the internal resistance of the battery and slowly lower the end voltage and the life of the battery. 

your test on the older batteries show a lower spike and im sure this is because of a higher internal resistance of the batteries, due to age and how they are used.

i will charge lipo,s at 2c but i dont charge my cheap li-ions at more then 0.20c, but thats some great info there, nice work the graphs make it nice and clear.


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## benckie (Aug 15, 2011)

well i made a 6 cell balance charging lead from 2 x 3s balance leads in series with a 2 x 3s to 6s series adaptor so i can balance charge 6 x 18650,s at once, it can be broken down to make 2 x single 3s balance leads and with the 2 x 3s to 6s series adaptor i don't have to use main charge leads to the magnets.

revision 1

i cut the yellow xt60 plug off and added two 4mm bullet connectors and some heat shrink to plug straight into the charger, i brought a couple of these from hobbyking for under 3 bucks each and have used them for rc.






2 x 3s balance leads with 8 x 8 mm nickel coated rare earth magnets soldered on the end's, with a bit of heat shrink added to keep the balance wires in pairs.






all joined together, the balacnce leads simply plug into the adaptor.






all plugged into my icharger and p350 power supply, with 6 x 18650 trustfire flame batteries






individual cell voltage's






it cost around 15 bucks to make most of the cost was the magnets, ill shorten the leads i think and ill make some thing similar using a flat pack battery holder soon.


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## benckie (Aug 23, 2011)

my old man pinched my 2s balance charge lead for his torch so i had to make another, i used shorter 22 awg 20 cm 2s balance extention lead and cut of the female end and used 18 awg main charge leads as the bigger stuff is not needed for these low charge rates and the usual male 4mm bullet connectors to plug in to the charger, lucky i had 3 magnets left over from my other leads i made.


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## benckie (Oct 12, 2011)

I have got my battery holders from www.luminousdiy.com its a pity Chris is no longer going to be selling them

2 x 18650 and a compact 6 x 18650 (3 top 3 bottom)







I'm going to make these into balance charging box,s


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## benckie (Oct 12, 2011)

2S balance revision 0






ill neaten it up a bit but so far i like it better then the magnets.


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## jenskh (Oct 12, 2011)

Here is my setup:





I have placed both the charger and the charging cradles in a metal toolbox as an extra precaution.
The charging cradles are made from cheap chargers bought on e-bay, where I have ripped out all electronics, and soldered wires to the positive and negative terminals. This way, I can set up this as I want parallell or in series. Normally I use it in series with balance leads connected. All actual battery sizes fits. I can charge any number of batteries (at current up to four) by just moving the positive wire from the charger. This looks a little messy, but is very easy to use. I have earlier used magnets, but found it very cumbersome to get all the balancing leads in correct position.


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## benckie (Oct 12, 2011)

Looks good, the magnets can be painful when they keep clanging together when your trying to set up some batteries for charging, the rare earths are prity dam strong, I believe my 6 x 18650 compact holder is going to be messy with all the balance wires going from side to side


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## DFiorentino (Nov 21, 2011)

Technically, this probably doesn't belong here, but since I do have it hooked up to my iCharger's balance port (1S) here you go:

1S6P charging clamp station...











Built to take the pain out of the few hundred battery tests I've done and am doing recently.

-DF


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## Battery Guy (Nov 21, 2011)

rmteo said:


> Also, since you are charging loose cells, there is no need (or advantage) to balance charge them in series - just charge them in parallel. Here's how I charge 1-8 cells at the same time.



rmteo

Where did you find that awesome cell holder? I have been looking for a multi-cell, parallel holder like that for charging 26500 and 26650s in parallel, but I have not been able to find one.


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## Battery Guy (Nov 21, 2011)

Mr Happy said:


> Not necessarily. Some lithium ion cells show improved internal resistance after a few cycles from new. There can therefore be an advantage to "breaking in" lithium ion cells to get the best performance out of them.





45/70 said:


> Hi Mr H. I've seen this suggested from time to time, however I've never seen where any manufacturer recommends a "break-in" for Li-Ion cells. Maybe this applies to the newer high cap cells with the nickel safety layer?



If the cell manufacturer knows what they are doing and the cells going out the door are fully formed and aged properly, then there is no need or advantage of running a break-in cycle. Unfortunately, many cell manufacturers either don't know how to properly perform formation on their cells, and/or they shortcut the aging process to get product out the door. If you get cells from these manufacturers, then a couple low rate charge/discharge cycles may indeed help improve internal resistance and stabilize capacity.

Cheers,
BG


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## Justin Case (Nov 21, 2011)

Battery Guy said:


> rmteo
> 
> Where did you find that awesome cell holder? I have been looking for a multi-cell, parallel holder like that for charging 26500 and 26650s in parallel, but I have not been able to find one.



That rig looks like a row of Bulgin BX0123 holders.


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## 45/70 (Nov 21, 2011)

Battery Guy said:


> Unfortunately, many cell manufacturers either don't know how to properly perform formation on their cells, and/or they shortcut the aging process to get product out the door.



Well, that's not exactly reassuring to hear LOL!

I have to say though, that even with cells of unknown origin (think CrapiFire, BangiFire etc.), I have never witnessed a Li-Ion cell that improved with cycling. There have been minor variations in tested capacity from time to time, but this goes both ways, higher and lower. I have attributed this to difference in room temperature, difference in time since the cell was last charged/discharged etc. And, as I've said before, other than hearsay, I've never read, or heard anything from a reputable source, that any Li-Ion cells require, or benefit from cycling.

Dave


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## eatkabab (Dec 31, 2011)

I'm trying to simplify and shrink the connector for a battery pack I'm making out of 2 RCR123's to be run in parallel and was wondering if the following setup would be a safe charging method.






I'd rather use a TRS connector rather than a TRRS for simplicity and the increased difficulty of four wires rather than three. I would also like to avoid having to use a hobby charger (trying to make this thing idiot proof). I figure the dangerous aspect of using lithium batteries is charging them, so I want to make sure I have that down. I figured this would be the best place to ask this given that you guys are thinking outside the box(es).

Thank you!


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## MikeAusC (Dec 31, 2011)

TRS connectors will short out the battery when you insert or remove the plug!!! 

Also you may not be able to connect together two terminals of the charger.


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## eatkabab (Dec 31, 2011)

MikeAusC said:


> TRS connectors will short out the battery when you insert or remove the plug!!!
> 
> Also you may not be able to connect together two terminals of the charger.



With the orientation that I've drawn above, the batteries shouldn't short when inserted/removed because the (-) terminal won't make contact until it's all the way in. That being said, I know there are points when one contact will touch 2 'bands' on the connector. Again, with the ground being the last thing to make contact, this shouldn't be a problem.

Just a question; each cell has it's own protection circuitry so if they were shorted upon insertion/removal, would it shorten the life of the battery or it's PCB at all?

As for your other point, that's what I'm worried about. Will the charger be able to read the two voltages independently from a single ground contact and separate (+) contacts?


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## Mr Happy (Dec 31, 2011)

eatkabab said:


> Just a question; each cell has it's own protection circuitry so if they were shorted upon insertion/removal, would it shorten the life of the battery or it's PCB at all?


It's not an "if" that should be contemplated. Simply make sure that under no circumstances can the battery positive and negative terminals be shorted together. Neither during partial insertion/removal of the plug or any other means. If the plug is of a kind where that can happen, then use a different design of plug.



> As for your other point, that's what I'm worried about. Will the charger be able to read the two voltages independently from a single ground contact and separate (+) contacts?


In your diagram, you have Ch1 and Ch2 negative terminals of the charger connected together by the black wire. In other words, you have made a short circuit. You might damage or upset the operation of the charger by doing this. You should not do it unless you look inside the charger and determine that such a connection already exists in the internal wiring.


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## eatkabab (Dec 31, 2011)

Mr Happy said:


> In your diagram, you have Ch1 and Ch2 negative terminals of the charger connected together by the black wire. In other words, you have made a short circuit. You might damage or upset the operation of the charger by doing this. You should not do it unless you look inside the charger and determine that such a connection already exists in the internal wiring.



So in essence two circuits sharing a ground connection are still independent? The ability to monitor voltage independently and charge independently is only limited by the charger electronics? As in, I can just build my own two channel charger.....and make it work.......?


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## Mr Happy (Dec 31, 2011)

eatkabab said:


> So in essence two circuits sharing a ground connection are still independent? The ability to monitor voltage independently and charge independently is only limited by the charger electronics? As in, I can just build my own two channel charger.....and make it work.......?


If you have two circuits that are completely isolated and independent from one another then making a one wire connection between them will not upset them. However, two charger circuits on the same power supply are highly unlikely to be independent. If two circuits are dependent and you connect them in the wrong place you will upset them.

I'm not saying you can't make the connection shown in your diagram, I am saying you must check it is OK to do so before going ahead. That check involves looking inside the charger to see how the circuits are arranged. The charger may internally have a common "ground" either on the positive side or the negative side of the batteries. You cannot tell without looking.


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## xxgg (Feb 23, 2012)

Hello,

I am just wondering,

How much 'amp' do you guys use to charge your batteries?

Is it safe to charge at 1C rate ?


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## benckie (Feb 23, 2012)

Depends on the cell I charge from 0.5 to 1 amp


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## KiwiMark (Feb 24, 2012)

xxgg said:


> Is it safe to charge at 1C rate ?



Most cells should be OK with it, but I'm rarely in a big hurry so I normally charge at around 1/2 C.


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## JargonGR (May 15, 2013)

I know this is a thread resurrection but I have wasted so much time looking for a ready made "perfect" cradle that would accept all types of LiPo cells for charging that I honestly fed up. The easiest most convenient method up to now is LuxLuthor's method but I am not good with soldering and this is because I have invested almost zero time on it. 

Nonetheless I won't give up and will continue to look for a nice neat way to do this job done. Upon searching I stumbled upon these products which are not made for LiPos but it is some food for thought. I don't even want to think how much they will charge for those judging from the what they do but still it would be nice if someone could make something like this for LiPos. 

Just an idea. 

Here is the link to their site: http://www.muchmoreracing.net/us/sub/sub.htm

And some photos:


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## Nisei (Feb 17, 2014)

*Balance charge cRe: Tech Tricks: Homemade Balance Charging Cradles.*

Thread Merge - Norm

thanks Norm
Doh, now my post doesn't make sense anymore. All the info seems to be in this topic 
I'll post a pic when I've finished it.


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## Nisei (Mar 7, 2014)

Mr Happy said:


> The charger may internally have a common "ground" either on the positive side or the negative side of the batteries. You cannot tell without looking.


You can, just use a multimeter to measure if either the positive or negative terminals are connected.
and if neither of them are I'd suggest using a 4-pole TRS connector. They are quite common nowadays since a lot of headsets with built in mic are using them.


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## Nisei (Mar 9, 2014)

Just finished my cradle which I've built using a dead Nitecore i4.
I wanted a nice looking unit without loose wires I had to attach using magnets and I've always liked these spring loaded chargers that can take different sized batteries.
When looking at the back I thought perhaps it would be possible to fit the balance ports in the same space where the mains connector was and when measuring it it turned out to be the exact same width as a 2S and 3S socket next to one another and the exact same height as 2 sockets on top of each other; perfect!
So the first thing I did was strip most parts from the PCB and making sure all terminal points I was going to use were isolated from the rest of the board. I did this by scratching away any unwanted board traces with a hobby knife.
I then took a couple of sockets and soldered them onto a piece of perfboard and hot-glued that to the main PCB. Then it was a case of soldering all wires into place and triple checking if everything was in the right place and there were no shorts. I then popped all parts into place, added some labels and it was finished. When charging less than 4 batteries at a time I'm using dummy batteries in the remaining slots. It's working like a charm.
Thanks for all the info in this thread!


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## Nisei (Mar 20, 2014)

OK so that was the last time I make an effort of taking pictures and posting.


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## Aahhyes68 (Mar 20, 2014)

Nisei said:


> OK so that was the last time I make an effort of taking pictures and posting.




No,no, no,no,no....... You did a great job ! I've asked questions about doing this same thing with an i4 but it never came to fruition. I like it !! I just revisited this thread so your work is NOT going unappreciated !!

Thanks for posting !!!


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## spencer (Mar 20, 2014)

Nesei, I really like what you did. It is very clean. I have also converted an old spring load but I don't have it set up for balance charging because I only just got a balance charger. I was parallel charging up to 4 cells at a time.

Something I noticed is that there is a very significant amount of resistance in the springs. At higher charging currents this resistance translates into a voltage drop. As a result, when the charger is putting out 4.200V and goes into CV mode, the battery voltage is really only about 4.050V. As a result I have to charge quite a bit at the end at a very low current. I have to reduce current to about 500mA to make the voltage drop negligible. When charging 4 18650's this way, it takes a very long time to top up cells (125mA per cell).

Nesei, have you noticed any negative effects in terms of any additional resistance added by the wire? It is possible that your wires are of a lower gauge than mine and have less resistance. Looking at how it is hooked up and some intuition, the effect should not be as pronounced in a series situation. I could also be totally wrong on that point.

Does anybody have any suggestions to counteract this effect in a spring load charger? Right now I'm thinking about just throwing the whole unit out and making a setup similar to the one in the OP. I don't really need to charge anything other than 18650 cells right now and I do like his second version. Decisions, decisions...


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## Nisei (Mar 21, 2014)

Thanks for the feedback Aahhyes68 and spencer.
Yes spencer, the resistance in the springs is a b|tch when it comes down to discharching. I haven't noticed any side effects when (balanced) charging though. Everything's fne when charging either 1, 2, 3 or 4 batteries but discharging is a no-go as voltage seems to drop to sub 3V within seconds after pressing the enter button. I'm gonna do some measuring with my Fluke to see what's actually going on.


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## keefd (Apr 28, 2014)

Ok, I know this is an older thread, but I'm a bit confused on the wiring. I'm not a total electronics novice, but I could use an explanation.

I get how power flows when the cradle Nisei built is loaded with 4 cells, but isn't the V+ in broken when using less than 4 cells? It looks like you'd load starting from the left going right, but say if you did 3S1P, what takes the positive voltage from the top right terminal to the V+ terminal to the left when there is no fourth cell to carry the voltage? The orange wire normally wouldn't act as V+ in a 3S arrangement, you'd unclip the red wire from the 4S position and clip it to the 3S position.

Or is the charger's original circuit board still functional? I assumed that the board was completely bypassed. Or is the i4 charger completely functional with the hobby charger supplying 12V, but how? My 106b+ won't send out even close to 12V in a 1S or 2S confuguration, unless the charger doesn't need +12V. I'm also a little confused as it looks like the balance wires are also pulling double-duty as power and neutral wires. Unless the cut traces on the underside are to disable not only the AC, but to disable the +12V as well.

I got mostly confused as I ordered a similar holder to this: https://highdesertvapes.com/products/4X-18650-Battery-Holder.html (link as an example) and I wondered how to wire it up so that I don't have to move the power leads around when doing less than 4S.

(sorry for the long post!)


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## Nisei (Jun 4, 2015)

keefd said:


> Ok, I know this is an older thread, but I'm a bit confused on the wiring. I'm not a total electronics novice, but I could use an explanation.
> I get how power flows when the cradle Nisei built is loaded with 4 cells, but isn't the V+ in broken when using less than 4 cells? It looks like you'd load starting from the left going right, but say if you did 3S1P, what takes the positive voltage from the top right terminal to the V+ terminal to the left when there is no fourth cell to carry the voltage?


It's covered in one of the last sentences of my post:
_When charging less than 4 batteries at a time I'm using dummy batteries in the remaining slots._


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## kreisl (Jun 4, 2015)

Great thread i must have missed it before.
I used to use diy solutions too.



Not anymore. Some ppl know why


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## Nisei (Jun 4, 2015)

I've been neglecting certain hobbies for a while (I've got too many) but I really would like this thing to become useable.
Is there a technical person here who can explain why my cradle (see above) won't work? All I can think of is that in the original i4 charger they've taken the resistance of the springs into account when the charger is measuring the cells.


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## Gauss163 (Jun 5, 2015)

If it were due only to resistance of the the springs then presumably you'd see a symmetric effect when charging. Are you sure that you cut enough traces to take all original components our of your circuit? It shouldn't be that difficult to troubleshooting using a DMM.


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## Nisei (Jun 7, 2015)

Yup, all traces are isolated. If you look at spencer's reply (7 posts up) he was having the same problem.
Probably also the reason why they've started using these metal rails in the newer versions of the charger.
I guess there's not much I can do about it.


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