# Blame the Battery ....



## old4570 (Aug 27, 2010)

Well as the heading suggests , seems a lot of folks blame the battery when something goes wrong ...

Lets get one thing straight right away - Li-ion's have the potential to be DANGEROUS ! This is a fact no one should underestimate ...

A lack of knowledge or due care can result in potential disaster ...

Buying cheap cells has its risks , quality control , discharge capability , and even internal capacity ..

These things may not be an issue in single cell lights ... In fact all you may suffer is diminished output and shorter run time , possibly even longer run time [ BRC3000 ] . 

And in no way does it mean that buying expensive cells is safe , lets get that straight as well , what you hopefully are buying is better quality control and more closely matched cells in terms of performance ...

Single cells lights will always be safer than multi cell lights , its just a Li-ion fact ..

The more cells you run , the greater the risk , especially in series ..
Most of the incidents involve multi battery set ups , is from what I would consider a lack of due care on the users part ..

So lets for a moment look at what U the multi battery user should be looking for ...

To start with , OFF THE CHARGER !

Dont , ever , pull the batteries off the charger , measure voltage and then throw them in a light .. It takes 30 minutes to 60 minutes for the battery to stabilize .. Fresh of the charger it might give a reading of 4.2v after 30 minutes it could be 4.19v or 4.18v and after on hour it could be down to 4.15v .. It depends on the quality of the individual cell .. Fresh readings can give you a false battery state , you need to establish the quality of each cell you use ... Are you doing this ? 

Next , discharge capability .. The higher performance the light [ the more current it draws ] the more important it becomes to match the discharge of the cells . Are you matching the discharge capability of your cells ? 

Cell capacity , again can vary some what , more possibly with cheap cells . Imagine if you will one cell has 2400mA capacity while the other may go 2550mA , 

What can happen : When you dont match the cells or use due care ...

Of the charger .. You think there fully charged , but one cell sags to 4.15v and the other does not .. Its not a huge variable , and under low current applications may be nothing worth worrying about ..

Next Discharge capability , one battery [ lets say the one that goes 4.15v after a bit of sag after charging ] has less discharge capability , whilst the other has very good discharge capability ...
Lets say you light draws 1.5A @ 8.4v for 12.6W [ SSC P7 for arguments sake ] What we may find is that the not so good cell gets stressed much worse than the good cell , and over a short time degrades even more ..
To the point that the two cells are dangerously out of balance . And lets not forget the real capacity of each cell , if its out , it will contribute to an out of balance state ...

Seems a lot of incident occur with new lights , and the operators dont test anything , and assume too much ..

Mixing used with new cells also seems to be an issue .. 
How many actually own a multimeter ? 
Im sorry , blaming the battery ? Sure you need a scape goat , I can understand that , its the way of the modern world , no one seems to want to take responsibility for there own actions ...

You should 

If you use Li-ion in a multi battery set up , BUY A MULTI METER , if you dont , then dont dare post here how the batteries failed you and vented .. 

Let the batteries sit for a least one hour after charging , and then test them for voltage state ...

If you run a really high performance light , go to the trouble of matching the batteries for current delivery ...

Before charging the batteries [ after use ] test voltage state , take note of the position of the battery , you want them to be as close as possible after use .. You dont want to see one battery @ 3v and the other at 3.5v ..
Are you testing after use ? 

For single battery users , the only real issue is , shorts , over discharge , and making sure you have your charging method sorted out , monitor the charger if its does not terminate on completion ... 

If you fail to do your part , the batteries may fail you , dramatically and possibly dangerously ...

If you dont own a Multi meter , you Blind to whats going on , blind people dont see anything .. 

Dont go to the trouble of matching cells , again , you have no clue to whats going on ..

Dont test , and test more , how do you know whats happening ? 

Seems a lot of folks are prepared to pull the pin on a hand grenade and put it in there pants .. 

 Yeah , must be the battery ! 

When I hear this stuff , it makes me think of the idiots cleaning there guns and shooting a family member , because they didnt know the gun was loaded . 

Li-ion has the potential to be DANGEROUS ! 
And people have the capacity to be even more dangerous ..

So the only question remaining to be answered , are you a safe Li-ion user , or a Dangerous one ... 

I havent covered everything , but hopefully enough ! 

Be safe everyone ...


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## lctorana (Aug 27, 2010)

Great post. Well thought out.


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## don.gwapo (Aug 27, 2010)

Thanks. Learned something from you. So i'm a little bit on the safe side coz all my lights are single cell.


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## LEDAdd1ct (Aug 27, 2010)

What you say is true, and though not cause for alarm, is cause for thought, especially folks not familiar with multi li-ion setups. I am having a light made with 2x26650, in series. This has the potential to be dangerous, since they are unprotected and, as noted, in series. However, I _do _own a multimeter, I _will_ own a good charger, and I _will_ test the cells to see how closely matched they are. 

Like most things in life, this is a balance, with the responsibility on the user split between the physical and the mental:

Physical

1) Did you buy quality cells? 
2) Did you buy a quality charger that terminates properly?
3) Do you own a quality multimeter?

Mental

1) Are you aware of the proper care and feeding of said cells?
2) Do you know how to operate your multimeter?
3) Are you familiar with the terms commonly used with these cells?
4) Do you know who some of the electrical "experts" on CPF are to seek assistance from, or, do you have someone in your family/house/peer group knowledgeable in same?
5) Are you prepared to measure your cells, _especially_ in high drain, multi-cell configurations, for close voltages?
6) Are you aware of the current drain of the particular light you intend to use said cells in, and, the equations necessary to calculate, for a given set of cells with a given capacity, what an appropriate amount of runtime is? 

I believe that to paint the [potentially] dire consequences as entirely the fault of the goods or entirely the fault of the user is constructing a false dilemma, when, in fact, the responsibility is shared between the two. Unsafe materials and/or oversight in materials handling are both dangerous. 

That said, this is a fine hobby, and there are many beautiful lights with li-ion cells and li-ion cells in series. However, each user must be prepared to undertake the responsibility in obtaining the proper _goods_ and learning/maintaining the proper _behaviors_ to use them safely. Good behaviors over time become good habits, and it is a measure of both the material [goods] and immaterial [behaviors] that is required for safe operation in the li-ion realm.

Most important of all, there is nothing shameful in asking for help. Every member of this board had a "1" in the top right corner of their posts at one point in time. If you are new to these cells, this chemistry, or this hobby, read the many well-written articles already posted by members, search, and if you are at all uncertain, ask!

:thumbsup:


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## old4570 (Aug 27, 2010)

Was I trying to scare people , a little !

At the very least , to respect the Li-ion's power . 

To possibly impress upon them the higher standards needed when taking greater risks . And I think multi battery use has proven itself , some what risky , and in need of some care . 

:wave:

Anyone can drive a car at 10MPH , it takes great skill to drive one at 200MPH


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## TooManyGizmos (Aug 27, 2010)

~

YEP ....... that pretty much sums it up .



( Learn how to pack that parachute properly ..... BEFORE you take the LEAP !)

~


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## mrartillery (Aug 27, 2010)

Very nice thread! Li-ions are very under estimated, hopefully a lot of people will read your post.


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## LuxLuthor (Aug 27, 2010)

Old4570, that was an excellent post, and demonstrated most of the key points. Only thing I would add is to say "*Generally*, buying cheap cells has *higher *risks..."

Again, thanks very much for this post! :thumbsup:


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## flatline (Aug 27, 2010)

Which of these risks remain when using Lithium Manganese chemistry cells?

--flatline


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## Battery Guy (Aug 27, 2010)

flatline said:


> Which of these risks remain when using Lithium Manganese chemistry cells?
> 
> --flatline



Lithium Manganese Oxide (aka LMO, spinel, manganese) cannot be overcharged. Unlike all other lithium-ion cathodes (except LiFePO4), the LMO cathode is completely exhausted of lithium ions at the top of charge. Charging to higher voltages may damage the electrolyte and hurt performance, but it will not result in an unstable, unsafe cell.

In comparison, you have only removed about half of the lithium ions from an LiCoO2 cathode at 4.2V. If you charge to higher voltages, you will continue to remove lithium and put charge into the cell. So overcharging an LCO cell to higher voltages puts more stored energy (more Watt-hours) into it, and it also makes the cell more thermally unstable. Picture old, sweaty TNT and you will have the right idea.

This is one of the big safety advantages of both LMO and LiFePO4 lithium-ion cells.

However, what everyone must remember about ALL lithium-ion batteries is that they use a combustible electrolyte. The combustion energy of the electrolyte is actually equivalent to the stored electrical energy of the battery. Basically, all bets are off if you ignite that electrolyte, no matter what type of lithium-ion cell you have.

Cheers,
Battery Guy


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## Battery Guy (Aug 27, 2010)

I don't know much about most things, but when it comes to batteries I feel that I am relatively up-to-speed with what is going on.

When it comes to lithium-ion, I would say that I am at the top of my game. I have been working professionally in this field for over a decade, in research, manufacturing, safety and application development.

So, when I say that I don't feel ready to use lithium-ion cells in my own personal flashlight modifications, I hope that some of you take this to heart.

When I do start using lithium-ions in my flashlight mods (and that may be relatively soon), I will only use cells from known, top tier cell manufacturers. Since cells from these manufacturers tend to be hard to come by, I will likely harvest cells from a power tool or laptop packs. I will NOT use protected cells. I will either charge the cells individually outside of the flashlight or build a custom pack with balancing leads and use a balancing charger. 

For what its worth.

Cheers,
Battery Guy


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## ASheep (Aug 27, 2010)

Congrats on a well written post old4570.

People should not be scared of lithium-ion cells, but have a *healthy respect *for them, much the same as one would have a healthy respect for venomous snakes. If you treat them properly, they PROBABLY won't harm you.

This is a great resource for newer members, or people just starting out with lithium-ions. Before I began using Li-ions, I read and reread every warning, MSDS, care and handling sheet, explosion story and general battery rant I could find. A sound knowledge of chemistry and materials science helped too. 

I think in addition to the "threads of interest" in the battery sub-forum, there should be a collection of safety threads. This would be a valuable resource for any user of li-ion cells.

Edit: While I was writing this, battery guy made his post above, I must say that the more you know about li-ion cells, the more reluctant you would be to put them inside a pressure vessel. As for unprotected li-ions, I find too many people think that because their cells are "protected" they won't fail. They run the cells down until the protection kicks in, slap it in the charger, dump it back in the light hot off the charger. This is plain unsafe, and bad practise. These suckers aren't your garden variety Ni-MH cells, where the worst that can normally happen is a bit of "sticky goop" (electrolyte) coming out. 

A piece of advice for all people using li-ions in lights: Measure the overall current draw from the battery on each mode you use. KNOW how long your light can theoretically last on your cell's capacity, and then take 10-20% off that, for a safety margin. 
I'd rather carry a spare 18650 battery or two individually cling-wrapped in a keep2go tube or similar, than risk killing my battery from overdischarge, or worse, a vent situation from mis-handling. If in doubt, swap out the battery. Always take the most cautious path, not the easiest.


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## jacknife (Aug 27, 2010)

I am only using AW protected 18650's , and panasonic cr123's, I have a ZTS-MBT1 tester. I have tested all lights with the CR123's. and on the ZTS tester they are all running at the same percentage, I have not yet tested the 18650's,that are in lights now. If I have one light, that is operating off one 18650, At what percentage on the ZTS tester, 80% , 60% ,40%, 20%, should I recharge that 18650? If I am running 2 -18650's in another light, should these 18650,s-- AW protected,,Be always running at the same percentage ??? like is one at 80% and one at 60% bad? I am guessing yes here. -And may I ask at what percentage would you throw away The CR123 batteries?----- And how often do you guys check the batteries you are running in your lights? I know it sounds like I am asking a lot But I am trying to learn MORE. What is the difference between the ZBT tester and the Multi Meter? do I need that too?


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## ASheep (Aug 27, 2010)

Jacknife, I recommend you get a digital multimeter to test voltages as well as your ZTS tester. The Multimeter will allow you to match the cell voltages closely, as having two 18650 cells in series with different voltages could be catastrophic. Running Li-ion cells, or even regular lithium CR123 cells at different states of charge (eg 80% and 60% reading on the ZTS) and different voltage (3.7V and 4.13V) will greatly increase the chance of one of the cells reverse charging, venting, and possibly damaging the light and you. 

It is not recommended to drain Li-ion cells below 3.0V for longevity, Below 2.7V will begin to damage the cell. 
I advise you read the articles on: 
http://www.batteryuniversity.com/index.htm
They are full of great advice, and explanations of the innards of your cells.

Stay safe,
Alex


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## jacknife (Aug 27, 2010)

Battery University ,,pretty cool. Which Multi Meter should I get --one from ZBT?? Suggestions??


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## ASheep (Aug 27, 2010)

There are many threads on CPF about cheap multimeters:
https://www.candlepowerforums.com/threads/188177
https://www.candlepowerforums.com/threads/283653

From these, in the US it seems Radio Shack, Harbour Freight and Sears seem to have reasonable quality Multimeters. 
I have an ancient analogue Voltmeter, and a rather old parameters multimeter, both of which are still very accurate (within 0.01V tested with a known 5.0V source) and some newer budget multimeters from **** Smith Electronics here in Australia. They are probably the same ones you could buy at harbour freight in the US.


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## LuxLuthor (Aug 28, 2010)

jacknife said:


> I am only using AW protected 18650's , and panasonic cr123's, I have a ZTS-MBT1 tester. I have tested all lights with the CR123's. and on the ZTS tester they are all running at the same percentage, I have not yet tested the 18650's,that are in lights now. If I have one light, that is operating off one 18650, At what percentage on the ZTS tester, 80% , 60% ,40%, 20%, should I recharge that 18650? If I am running 2 -18650's in another light, should these 18650,s-- AW protected,,Be always running at the same percentage ??? like is one at 80% and one at 60% bad? I am guessing yes here. -And may I ask at what percentage would you throw away The CR123 batteries?----- And how often do you guys check the batteries you are running in your lights? I know it sounds like I am asking a lot But I am trying to learn MORE. What is the difference between the ZBT tester and the Multi Meter? do I need that too?



Thanks for asking about this. You are exactly the kind of member that we want to reach and help you avoid problems. We all started where you are. 

As ASheep answered so well, the digital multimeter (DMM) should be seen as a standard required item if you use Lithium batteries (primary or secondary-rechargeable). I also have and use a ZTS tester, but I use it for Alkaline and NiMH cells.

There is a great guideline here to see where you are with Lithium Ion cells:*4.2 volts 100%*
* 4.1 about 90%*
* 4.0 about 80%*
* 3.9 about 60%*
* 3.8 about 40%*
* 3.7 about 20%*
* 3.6 empty *
​Most protection circuits prevent charging above 4.25V, and discharging below 2.5V. When a cell is empty, it has a sharp spike downward, so even if it quickly goes to a cell damaging low voltage of 2.5V before the protection PCB breaks the circuit, the cell will rebound back up above 3.1V very quickly if it is healthy, and avoid harming it. One of the best threads on the subject was from one of the truly Great Past Members of CPF, Newbie, here.

If you are using two Li-Ion cells together, I try to make sure they are within 0.05 to 0.10 Volt of each other (i.e. 4.12 & 4.18V are close enough; 4.0V & 4.2V are too imbalanced to use together.)*--------------------------------------*​Your other question was seeking guidance on CR123A (primary Surefire type cells) voltages. First, make sure you bought cells from USA manufacturers. Since these are never charged, they are going to start at around 3.25V and only go down. 

When they get down to 2.7 to 2.8V range they are nearly empty, some have drained them to 2.5V. There is less concern about draining them if being used in a single cell light. In multi-cell lights mainly look for voltage imbalance between the cells. A pair with 2.8V & 2.91V would concern me less than a pair of 3.1V and 2.99V, because there is more energy in the latter pair.*--------------------------------------*​*Here is something I find curious and cannot explain. *

I have various used Surefire CR123A cells. If I check the voltage with two of them having *05-2015* dates on their side, my Fluke 189 DMM gives a reading of *3.05 Volts*. Putting those cells on my ZTS (MBT-1) CR123 + terminal, it reports *10% remaining*.

I have two other SF cells with *05-2018* dates, that measure *2.91V*, but on the ZTS, they report *40% remaining*. Neither pair have been recently used. I suspect it must have to do with the dates, but the resting voltage becomes confusing.


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## LuxLuthor (Aug 28, 2010)

Battery Guy said:


> When I do start using lithium-ions in my flashlight mods (and that may be relatively soon), I will only use cells from known, top tier cell manufacturers. Since cells from these manufacturers tend to be hard to come by, I will likely harvest cells from a power tool or laptop packs. * I will NOT use protected cells.* I will either charge the cells individually outside of the flashlight or build a custom pack with balancing leads and use a balancing charger.
> 
> For what its worth.
> 
> ...



BG, first make sure you read that thread by Newbie. You especially will appreciate it. You remind me of him.

Could you share your thoughts/concerns on not using protected cells? There is a reinforced idea (whether right or wrong) of the PCB providing a layer of insurance, but it is hard to test if all of its components are working properly. There are also more known incidents here of primary Lithium cell problems than secondary, which lulls us into perhaps feeling more secure using them than we should.

Thanks.


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## jasonck08 (Aug 28, 2010)

LuxLuthor said:


> *4.2 volts 100%*
> *4.1 about 90%*
> *4.0 about 80%*
> *3.9 about 60%*
> ...



Really depends on the cell itself, these figures are quite off for some cells, such as a 3.6v nominal Samsung 2200mAh cell I tested recently. Here were my capacity results from this cell:

4.20v - 100%
4.08v - 90%
3.96v - 80%
3.84v - 70%
3.74v - 60%
3.66v - 50%
3.61 - 40%
3.55 - 30%
3.51 - 20%
3.47 - 10%
3.31 - 0%

These are resting voltages taken after discharging the cell 10% of its actual capacity and then measuring the resting voltage after 10 minutes.
​


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## LuxLuthor (Aug 28, 2010)

jasonck08 said:


> Really depends on the cell itself, these figures are quite off for some cells, such as a 3.6v nominal Samsung 2200mAh cell I tested recently. Here were my capacity results from this cell:
> 
> 4.20v - 100%
> 4.08v - 90%
> ...



I agree there is variation among most cell brands, further complicated by variation in models of a particular brand, and then between cell batches of the same brand model, age of cells, and degrees of use/abuse over time, but are nonetheless useful guidelines often posted by knowledgeable members, such as Silverfox.


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## flatline (Aug 28, 2010)

Battery Guy said:


> When I do start using lithium-ions in my flashlight mods (and that may be relatively soon), I will only use cells from known, top tier cell manufacturers. Since cells from these manufacturers tend to be hard to come by, I will likely harvest cells from a power tool or laptop packs.



So does that mean that the only quality cells available are 18650s? Or do top tier cell manufacturers also make RCR123s?

The reason I'm asking is that I finally broke down and bought a 1xCR123 light (HDS high-CRI clicky) and 2 protected AW RCR123s. Is it your recommendation to just suck it up and use primary CR123 cells instead of rechargeable cells?

--flatline


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## LEDAdd1ct (Aug 28, 2010)

For the HDS, you can purchase the 17670 tube, and use AW cells.


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## Battery Guy (Aug 28, 2010)

jasonck08 said:


> Really depends on the cell itself



This is true, and the values that Lux gave should only be used as a general guide.

A long, long time ago (pre-2000), nearly all lithium-ion cells were made with essentially the same type of carbon for the negative electrode and LiCoO2 as the positive electrode. Today, there are different varieties of carbon and different metal oxides used, and these may shift the OCV at a given state of charge by 100 mV or more. There are even some commercially available lithium-ion cells that require charging to 4.3 V in order to be at 100% SOC. 

So there is no OCV vs SOC curve that works for all lithium-ion cells. Even cells that use LiCoO2 can be quite different because of differences in the type of carbon used and the anode:cathode balance. And to make things even more complicated, as a lithium-ion cell ages, the anode:cathode balance shifts and the OCV vs SOC relationship will also change.

So the best thing to do is exactly what you did: make your own curves for your own cells. There is no substitute for that.

Just remember that the amount of time that you let the cell rest will also affect the results. You might be surprised in the difference if you repeated your test, but let the cells rest for 2 hours instead of 10 minutes.

Cheers,
BG


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## flatline (Aug 28, 2010)

LEDAdd1ct said:


> For the HDS, you can purchase the 17670 tube, and use AW cells.



If BatteryGuy doesn't trust the quality of AW cells, I don't see how his recommendation would be different between AW 17670 and AW RCR123 cells.

--flatline


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## Fusion_m8 (Aug 28, 2010)

Thanks Matt, a.k.a Battery Legend!

:thumbsup:


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## Battery Guy (Aug 28, 2010)

flatline said:


> If BatteryGuy doesn't trust the quality of AW cells, I don't see how his recommendation would be different between AW 17670 and AW RCR123 cells.
> 
> --flatline



I never said that I don't trust the quality of AW cells. In fact, my experience with AW leads me to believe that he is fully aware of the quality issues among various cell manufacturers and sources his product very carefully. I would say that AW is an exception to the rule.

Cheers,
BG


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## Battery Guy (Aug 28, 2010)

flatline said:


> So does that mean that the only quality cells available are 18650s? Or do top tier cell manufacturers also make RCR123s?



The larger, more established cell companies tend not to mess around with the goofy cell sizes that have low sales volumes. Therefore, you will usually only see 18650s, 26650s and 18500s available for purchase or harvesting from OEM battery packs.

Of all of the top tier manufacturers, Sanyo seems to have the largest variety of cell sizes, and they do make a RCR123 (also called an LC16340). You can find them forsale on Battery Universe here.

Cheers,
Battery Guy


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## flatline (Aug 28, 2010)

Battery Guy said:


> I never said that I don't trust the quality of AW cells. In fact, my experience with AW leads me to believe that he is fully aware of the quality issues among various cell manufacturers and sources his product very carefully. I would say that AW is an exception to the rule.
> 
> Cheers,
> BG



I apologize for putting words in your mouth. I didn't remember seeing AW in your list of trusted manufacturers earlier (either in this thread or another) and just assumed that you didn't trust AW.

But I'm glad to hear your opinion of AW since I've got 2 AW RCR123 (16350?) cells on their way for my new light.

--flatline


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## jacknife (Aug 28, 2010)

Is there any Risk in testing Batteries, The ZTS tests under load, And I thought I read somewhere that you have to be careful testing with A multi tester, Is there risks testing batteries with any of these??


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## 45/70 (Aug 28, 2010)

Just a few quick comments. Regarding why AW's cells are preferred by many on these forums over other Chinese cells, it has a lot to do with experience. Some of us that have used both AW's and the others over the past 5-6 years, like myself, have seen a marked difference. AW's cells nearly always have more consistency from cell to cell than the other brands, which is critical for series applications. This doesn't mean that you will never get a bad cell from AW, but I never have. This is something I can't say about cells from other distributors, such as xxxxxFire. Also, new cells from AW nearly always have better voltage retention than the others. This is a sign that the cells that AW provides are newer. Keep in mind that unlike NiCd/NiMH cells, all forms of Li-Ion cells start to degrade significantly, from the day they are manufactured, whether they are used or not.

Another factor that those fairly new to using Li-Ion cells may not be aware of, is that just because a new cell performs well, doesn't mean that it will perform as well 10, 20, or 50 cycles later. In my experience, AW's cells outperform other distributor's in the long run. They retain usable capacity for more cycles, and retain their consistancy from cell to cell, far better than any of the others. That doesn't mean that you won't come across a good sample from the other distributors once in a while, but this very inconsistency is a problem. You can never be as sure, what you're going to get.

As I have mentioned in other threads over the years, I don't know how it is, that AW manages to provide better cells, but I suspect that he has a close relationship with one or more of the 3(?) Chinese Li-Ion cell manufacturers. This possibly allows him to get "first pick" among the surplus cells manufacturer's offer. This no doubt would cost him more, and the additional cost would obviously have to be reflected in the price of his cells.

As for determining the estimated capacity of LiCo Li-Ion cells by measuring the OC voltage of the cell, the various charts/tables that are commonly used, were never intended to be an absolute means of estimating capacity. Also, years ago, when most all Li-Ion cells on these forums were LiCo, it was understood even then, that voltage readings below 3.80 Volts were not as accurate, due to differences in the actual composition of cells from different manufacturer's. Jason's findings seem to reflect this.

Dave


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## LuxLuthor (Aug 28, 2010)

Guidelines are guidelines. In my posted guidelines which I got from Silverfox, there is the word "about" for each value. These are still better than having no guidelines, and however wonderfully accurate it may be to know the exact discharge graph for each cell you are using, re-evaluated at least once a year, and keeping track of all that as separate guides linked and meticulously scrutinized by people using a DMM to evaluate the cell state when removed from their flashlights is utterly preposterous. How many members using Lithium cells don't have a DMM, let alone an accurate and safe discharge testing setup? 

In the interest of fairness and full disclosure, while I also regard AW's cells as a quality exception coming from years of experience and reading these and other forums, I did get a bad batch of 8 x 17670 cells several years ago. Upon arrival, they would not charge consistently, or properly on Pila IBC; did not reach full charge voltages, and in retrospect were likely dangerous. I posted about them in a thread somewhere...I think in a Fivemega mod where I was intending to use them.

I had a number of PM's with AW in addition to posting in that thread to find out what happened as the cause. That was back in the day that Lithium Ions were still being mailed easily all over the place, and he did promptly replace them while I returned them to Hong Kong. From memory, I think he finally traced this to either a bad batch of electrolye, or bubbles in the electrolyte, or some problem with the electrolyte layering. I have never forgotten since then that it is my responsibility to make sure to fully evaluate cells, even if from a trusted source.


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## jasonck08 (Aug 28, 2010)

Battery Guy said:


> The larger, more established cell companies tend not to mess around with the goofy cell sizes that have low sales volumes. Therefore, you will usually only see 18650s, 26650s and 18500s available for purchase or harvesting from OEM battery packs.
> 
> Of all of the top tier manufacturers, Sanyo seems to have the largest variety of cell sizes, and they do make a RCR123 (also called an LC16340). You can find them forsale on Battery Universe here.
> 
> ...


 
Hmmm... Are you sure these are legit Sanyo made cells? Maybe discontinued? It seems like Sanyo would list them on their site if they still made them or if they were legit: http://battery.sanyo.com/en/product/lithiumion_2.html

The only cells I've seen from Sanyo are 18xxx and 14xxx cells.

Capacity also seems a bit high. 800mAh from a 16340. Sanyo's 14500 (which IIRC is about 10-20% greater volume then a 16340) is rated @ 800mAh.


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## Wiggle (Aug 28, 2010)

Why the recommendation to let cells sit before using? I can understand if it's multi-cell and you don't want one cell with a capacity different to sag more than the other but for average single cell use I don't see the risk. I top off the 14500 in my EDC light every day or two just cause I can and I always throw it right off the charger into my light.


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## old4570 (Aug 28, 2010)

Wiggle said:


> Why the recommendation to let cells sit before using? I can understand if it's multi-cell and you don't want one cell with a capacity different to sag more than the other but for average single cell use I don't see the risk. I top off the 14500 in my EDC light every day or two just cause I can and I always throw it right off the charger into my light.



For single cell use it would not be important .. But it would give you some idea of the state of the cell .. As cells get older they degrade , a degraded cell fresh of the charger may show 4.2v , but after one hour it will show a more true capacity state . Was 10% per year mentioned some where ? 

So if you have 1 year old cells , used or not , they may have degraded 10% , 2 year old cells 20% etc . Using old laptop cells of ?? state .. 
For single cells use , not really an issue , but for multi cell , great care would be called for to sort out the batteries .

Most of the flame events used to be with CR123A primaries , folks simply did not check the state of the batteries when feeding the flashlight , and accidents happen , fresh cells with used cells , or cells with differing voltages being used , with a great enough variation 

Now that multi cell 18650 lights are becoming ever more popular , we are starting to see flame events with the 18650 , and its a larger more powerful battery capable of doing more damage .

Some folks seem to think that because they use a protected battery they are safe , when nothing could be further from the truth . The PTC protects the battery from over discharge and charging , it does not protect you from stupid ! I dare say the PTC is giving some people a false sense of security , and may be contributing to unsafe practices .


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## Battery Guy (Aug 29, 2010)

45/70 said:


> ,,, I don't know how it is, that AW manages to provide better cells, but I suspect that he has a close relationship with one or more of the 3(?) Chinese Li-Ion cell manufacturers.



There are approximately 600 battery companies throughout China, and over 100 of those manufacturer lithium-ion cells. Most of the Chinese companies manufacturing lithium-ion are making pouch (aka "polymer") cells, but that still leaves a very large number making cylindrical cells like 18650.

I suspect that you are correct and that AW has relationships with several of the higher quality cell manufacturers in China, and works to insure that he is getting high quality product.

Cheers,
BG


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## Battery Guy (Aug 29, 2010)

jasonck08 said:


> Hmmm... Are you sure these are legit Sanyo made cells? Maybe discontinued? It seems like Sanyo would list them on their site if they still made them or if they were legit: http://battery.sanyo.com/en/product/lithiumion_2.html
> 
> The only cells I've seen from Sanyo are 18xxx and 14xxx cells.
> 
> Capacity also seems a bit high. 800mAh from a 16340. Sanyo's 14500 (which IIRC is about 10-20% greater volume then a 16340) is rated @ 800mAh.



No idea if they are legit. I only know that Sanyo has a reasonably good variety of cylindrical cells sizes, and I found those cells when I did a quick Google search.

Nice link to Sanyo's battery site, and good point about the capacity. That is certainly sufficient information to cause one to have some legitimate suspicion of these cells.

Although, one thing about a cylindrical cell is that they all have a hollow region in the center of the cell where the electrodes were wound around a mandrel. The diameter of this hollow area is relatively the same for all cylindrical cell sizes. Therefore, the smaller the cell diameter, the less efficient the overall electrode packing in the cell is going to be. So it would not be too surprising to me if a 16 mm diameter cell has a 10-20% higher volumetric capacity compared to a 14 mm diameter cell from the same manufacturer.

Cheers,
BG


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## Battery Guy (Aug 29, 2010)

LuxLuthor said:


> Guidelines are guidelines. In my posted guidelines which I got from Silverfox, there is the word "about" for each value. These are still better than having no guidelines, and however wonderfully accurate it may be to know the exact discharge graph for each cell you are using, re-evaluated at least once a year, and keeping track of all that as separate guides linked and meticulously scrutinized by people using a DMM to evaluate the cell state when removed from their flashlights is utterly preposterous. How many members using Lithium cells don't have a DMM, let alone an accurate and safe discharge testing setup?



Hey Lux

When I read your post above, my first thought was "what kind of idiot would recommend such a thing?". Then I realized that you were talking about me! 

In my previous post, I was not recommending that people make their own OCV vs SOC curves for their batteries. What I was trying to say is that if the guidelines that you posted are not sufficiently accurate for someone's needs, then that person should make his own curves...and that he would need to re-calibrate those curves after the battery ages.

It was not my intent to make that a general recommendation that all lithium-ion battery users follow. Although, rereading my own post I can see how it would be interpreted that way.



LuxLuthor said:


> In the interest of fairness and full disclosure, while I also regard AW's cells as a quality exception coming from years of experience and reading these and other forums, I did get a bad batch of 8 x 17670 cells several years ago. Upon arrival, they would not charge consistently, or properly on Pila IBC; did not reach full charge voltages, and in retrospect were likely dangerous. I posted about them in a thread somewhere...I think in a Fivemega mod where I was intending to use them.
> 
> I had a number of PM's with AW in addition to posting in that thread to find out what happened as the cause. That was back in the day that Lithium Ions were still being mailed easily all over the place, and he did promptly replace them while I returned them to Hong Kong. From memory, I think he finally traced this to either a bad batch of electrolye, or bubbles in the electrolyte, or some problem with the electrolyte layering. I have never forgotten since then that it is my responsibility to make sure to fully evaluate cells, even if from a trusted source.



Also in the interest of full disclosure, I have only purchased one cell from AW, and that was a 14500 for my AA Ragone Plot testing. Therefore, I have no real experience with the quality of AW cells, good or bad. However, AW does appear to have established a very good reputation for himself as being able to supply high quality lithium-ion cells of various sizes. Based on some of his posts on CPF, AW appears to have an advanced knowledge of lithium-ion cell chemistry, construction and manufacturing. 

Having one person who holds himself responsible for the quality of the product he sells, and is actually available via email or PM to answer questions, is worth a lot in my book.

Cheers,
BG


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## 45/70 (Aug 29, 2010)

Battery Guy said:


> There are approximately 600 battery companies throughout China, and over 100 of those manufacturer lithium-ion cells.



Are we talking manufacturers, or distributors? From what I understand, there are only a few facilities that actually manufacture cylindrical Li-Ion cells in China. Li-Poly, I have no idea. Unless you consider taking a cell, shrink wrapping it, and optionally adding a protection circuit as "manufacturing", I didn't think there were that many actual manufacturers, of cylindrical cells anyway.

Attempting to find this kind of information about companies in China is quite difficult, as it is sparse and not readily available. I know, as I've looked into it a bit. Seeing as you work much closer to the industry than I do, you may very well be correct, but your estimate conflicts with my findings.

My apologies old, but this is sorta, kinda, remotely, indirectly related to your thread...... maybe.

Dave


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## Battery Guy (Aug 29, 2010)

45/70 said:


> Are we talking manufacturers, or distributors? From what I understand, there are only a few facilities that actually manufacture cylindrical Li-Ion cells in China. Li-Poly, I have no idea. Unless you consider taking a cell, shrink wrapping it, and optionally adding a protection circuit as "manufacturing", I didn't think there were that many actual manufacturers, of cylindrical cells anyway.



There are somewhere between 50 and 75 cylindrical lithium-ion cell manufacturers in China. Very hard to ever know for sure as they are constantly changing hands, changing names, and new ones pop up all of the time. 

One of the things to keep in mind is that all battery companies have "scrap". By "scrap", I mean fully manufactured cells that for some reason do not meet quality requirements. Most of the large battery companies actually dispose of their scrap cells. However, I have know for certain that many of the Chinese manufacturers will resell their scrap to the highest bidder. Most of these low quality, "scrap" cells end up in foreign markets, but a few turn up with private labels and are sold online. I have personally witnessed this practice numerous times, and it is the reason that I will not buy private label lithium-ion cells unless I am very confident of the distributor.

Cheers,
BG


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## 45/70 (Aug 30, 2010)

Battery Guy said:


> There are somewhere between 50 and 75 cylindrical lithium-ion cell manufacturers in China. Very hard to ever know for sure as they are constantly changing hands, changing names, and new ones pop up all of the time.



After doing a bit of quick research, it looks like you're right, BG. While I didn't seem to find any list longer than 25-30 companies, if sorted and combined, there most likely are that many.

I did notice that at least a couple of these battery companies mentioned the use of Samsung, Panasonic, etc. cells, suggesting that they manufacture battery packs using cells sourced from actual Li-Ion cell manufacturers. Also, in my quick investigation it appeared that the majority of actual cell manufacturers do not produce cells smaller than 18650. This may have influenced my interpretation of the number of manufacturers that produce Li-Ion cells smaller than this, which I primarily use. Still, things are definitely changing, and my "guesstimate" was likely way off.

Dave


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## Battery Guy (Aug 30, 2010)

45/70 said:


> Also, in my quick investigation it appeared that the majority of actual cell manufacturers do not produce cells smaller than 18650.



Most of the lithium-ion cell manufacturers in China are going after the commodity markets (i.e. standard cylindrical and prismatic cell sizes) or the specialty LIP (pouch cell) markets. It wouldn't surprise me if there were only a handful making the "odd" cylindrical cell sizes because the market for those cells is very small compared to the other cell sizes.

Interestingly, I keep hearing rumors that several of the Japanese battery companies will be getting out of the standard 18650 commodity cell business because they are having a hard time competing on cost. 

It is a very interesting time to be in the battery business. 

Cheers,
BG


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## Mr Happy (Aug 30, 2010)

As a matter of interest, I caught a segment on "How It's Made" on the Science Channel concerning the manufacture of lithium ion cells. The example used was a US manufacturer where the lithium was mined, transported, processed and made into cylindrical cells here (there) in the USA.

I didn't catch the name of the manufacturer, but it would be interesting to know who it was and if those cells are available in small quantities anywhere (the normal application was automotive, I think).


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## qwertyydude (Sep 1, 2010)

It's possible the American battery on How it's Made was A123 Systems. Great technology and the safest as they won't explode but very limited in power density, only about 1100 mah on an 18650. Great cell to use if you need high current discharge as 18650 A123 cells can manage over 30 amps continuous discharge, and 4C recharge rate.


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## Battery Guy (Sep 1, 2010)

qwertyydude said:


> It's possible the American battery on How it's Made was A123 Systems. Great technology and the safest as they won't explode but very limited in power density, only about 1100 mah on an 18650. Great cell to use if you need high current discharge as 18650 A123 cells can manage over 30 amps continuous discharge, and 4C recharge rate.



A123 18650 and 26650 cells are made in Asia.

The Sanyo UR18650W significantly outperforms the A123 18650, both in terms of power capability and total capacity/energy. See a comparison here.

Cheers,
BG


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## forexer (Sep 1, 2010)

If the PCB is tripped does it render the cell useless forever? Or does the PCB reset itself after awhile under right conditions. Does the PCB trip when due to over charging / over discharging or doe sit also trip when the cell's temperature gets too high.


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## old4570 (Sep 1, 2010)

forexer said:


> If the PCB is tripped does it render the cell useless forever? Or does the PCB reset itself after awhile under right conditions. Does the PCB trip when due to over charging / over discharging or doe sit also trip when the cell's temperature gets too high.



If the Protection Circuit is tripped :
Get another cell , and connect the two in parallel , Positive to positive , and neg to negative , for about 1 second .. It might take a few tries , but hopefully it will re-set the protection circuit .
Unless the protection circuit has been damaged some how .


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## forexer (Sep 1, 2010)

old4570 said:


> If the Protection Circuit is tripped :
> Get another cell , and connect the two in parallel , Positive to positive , and neg to negative , for about 1 second .. It might take a few tries , but hopefully it will re-set the protection circuit .
> Unless the protection circuit has been damaged some how .


What are the most common parameters for the PCB to be tripped? And what does connecting the cells in parallel do to restore the circuit?


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## old4570 (Sep 1, 2010)

forexer said:


> What are the most common parameters for the PCB to be tripped? And what does connecting the cells in parallel do to restore the circuit?



Ok its usually over discharge ... 

Connecting the cells feeds power to the protection circuit , and usually the battery voltage has increased [ bounced back with no load ] so the circuit remains open and the battery can be charged ..

Less common , would be overcharging , a short , to much current , some have thermal protection , so to much heat . 

Over discharge is the main one ...


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## forexer (Sep 1, 2010)

old4570 said:


> Ok its usually over discharge ...
> 
> Connecting the cells feeds power to the protection circuit , and usually the battery voltage has increased [ bounced back with no load ] so the circuit remains open and the battery can be charged ..
> 
> ...


You've been very helpful to a newbie like me:thumbsup: Last question: What's the optimal voltage a average cell should be discharged to. Would you say no lower than 3V? I'm guessing the PCB kicks in at around 2.5ish volts?


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## old4570 (Sep 1, 2010)

3v max ! , some are rated lower , but there is very little power left in the cell bellow 3v , and there is the possibility of doing damage to the cell .

The protection circuit ? Some kick in around 2.75ish , dont quote me on that . and a few actually kick in just bellow 3v , 2.5v is a little low ...

Many here try to avoid going under 3.5v , as decent performance seems to drop of around this point , and doing so long term [ going under 3.5v ] may accelerate the degradation of the cell structure of the battery ...


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## LuxLuthor (Sep 1, 2010)

If you look at battery discharge curves, when the cells are empty, their voltage drops quickly and like a rock under load. As such, they spike down so quickly to reach the low voltage protection trigger, whether it be 2.5 or 2.8V and then rebounds back up to a safe 3.1+V that it does not damage the cell to any degree.

The problem comes when people use very low current applications that drifts down much slower towards the trigger low voltage protection so it spends more time below 3.0 V, or the person who repeatedly keeps using a battery that is empty before recharging. Some PCB's have their own reset voltage, so it it hits 2.5V and breaks the circuit, when the battery rebounds back up to 2.9V, it resets the protection break without having to do any external parallel connection or recharging.


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## Norm (Sep 1, 2010)

old4570 said:


> , some have thermal protection , so to much heat


Which batteries have this feature? This is something that I wasn't aware of. 
Norm


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## Battery Guy (Sep 1, 2010)

Norm said:


> Which batteries have this feature? This is something that I wasn't aware of.
> Norm



Most 18650 lithium-ion cells have a Positive Thermal Coefficient (PTC) device built into the crimp assemble. If the cell get's too hot, or too much current is drawn from the cell, the resistance of the PTC increases and limits the amount of current that can be drawn from the cell. The PTC is reversible, so when the temperature decreases, the PTC "resets" and the cell is back to normal.

The PTC is typically thought of as a safety feature to prevent thermal runaway caused by an external short circuit.

It is worth noting that some high power 18650 cells, such as those in many power tools, do not have a PTC because it restricts current flow too much.

The PTC should not be confused with the Current Interrupt Device (CID), which is also incorporated into the crimp assembly. The CID is activated when the internal pressure of the cell gets too high. When the CID is activated, a metal contact within the vent assembly is torn, opening the circuit so that no current can pass. Usually, CID activation occurs concurrently with vent activation. The CID and vent are not reversible in a lithium-ion cell, so the cell is effectively dead forever when this occurs.

Hope this helps.

Cheers,
BG


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## LuxLuthor (Sep 2, 2010)

Battery Guy said:


> Most 18650 lithium-ion cells have a Positive Thermal Coefficient (PTC) device built into the crimp assemble. If the cell get's too hot, or too much current is drawn from the cell, the resistance of the PTC increases and limits the amount of current that can be drawn from the cell. The PTC is reversible, so when the temperature decreases, the PTC "resets" and the cell is back to normal.
> 
> The PTC is typically thought of as a safety feature to prevent thermal runaway caused by an external short circuit.
> 
> ...



Is that the part that runs the highest risk of being damaged when people solder various cells (I'm mainly talking NiMH, but there is also a "crew of CPF members" that believe they can safely solder even to Lithium Cobalt)?


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## Battery Guy (Sep 2, 2010)

LuxLuthor said:


> Is that the part that runs the highest risk of being damaged when people solder various cells (I'm mainly talking NiMH, but there is also a "crew of CPF members" that believe they can safely solder even to Lithium Cobalt)?



While both the PTC and the CID are located within the crimp assembly, they are in different locations with respect to the current path. The PTC is connected to the negative electrode, and therefore the can. The CID is connected to the positive electrode lead, and therefore the "button". So it would be very hard to damage the PTC by soldering to either end of the battery. The CID is typically made of aluminum, and should not be damaged by soldering, at least not directly. If the process of soldering causes an internal short circuit, the pressure in the cell could rise and the CID would activate, permanently disabling the cell. So if you know people that this has happened to, tell them that they were damn lucky the cell didn't explode in their face.

My biggest concern about soldering to lithium-ion cells is the possibility that local heating might melt part of the separator or the thin insulation material that covers the leads to prevent shorting inside the cell. 

Cheers,
BG


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## VidPro (Sep 2, 2010)

Beep 
Li-Ion Batteries for $500 Alex 
The PCT resistance materials
What is, Not connected to the can

or should we say not always connected?
http://www.molalla.net/members/leeper/liion1.png
it would be sorta difficult for some of the cylindrical li-ions i have seen apart to have the PCT connected to the can, when the plates are right there down the sides, and the bottom on a good cell is gapped , so i can solder to them without messing up the internals 
its not rocket science, look how easy they are to dent on the bottom of the actual cell , for example.

mabey it is in some? but that statement just didnt make enough sence to me.

and LUX since when can you spot Weld without ANY heat, or do the metals just melt together via electronmigration  You should Not solder to li-ion cells, unless you can do it as fast as a spot welder


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## LuxLuthor (Sep 3, 2010)

VidPro said:


> and LUX since when can you spot Weld without ANY heat, or do the metals just melt together via electronmigration  You should Not solder to li-ion cells, unless you can do it as fast as a spot welder



Yeah, I use magic fusion.

All factory battery packs are spot welded, and the flash weld is so quick, I can immediately touch my finger on top of the weld spot, and perceive no heat. It's like magic.


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## VidPro (Sep 3, 2010)

LuxLuthor said:


> Yeah, I use magic fusion.
> 
> All factory battery packs are spot welded, and the flash weld is so quick, I can immediately touch my finger on top of the weld spot, and perceive no heat. It's like magic.


 
i solder so hot and so fast, that only a little smoke comes off my fingers when i touch the top of the solder spot , and most of that is just steam :laughing:

i am now up to about 400+ solderings of li-ion without a single lost Ma. and most of the stuff i wouldnt use a spot welder even for because i use lots of copper, and it is redundant to put tabs on, as opposed to direct. I would not use spot welding for raw wires, that doesnt wrap the wire in conduction, and i hate crimps. I cant see doing different for the parts and pieces i use. even if i toss on protection, i dont have manufactured metal strips of the exact lenght and all. its not manufactured.


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## Battery Guy (Sep 3, 2010)

VidPro said:


> or should we say not always connected?
> http://www.molalla.net/members/leeper/liion1.png
> it would be sorta difficult for some of the cylindrical li-ions i have seen apart to have the PCT connected to the can,



Oops, my bad. You are correct that the PTC and the CID are both on the positive terminal. Sorry about that.



VidPro said:


> when the plates are right there down the sides, and the bottom on a good cell is gapped , so i can solder to them without messing up the internals



The bottom of most cylindrical lithium-ion cells has a plastic spacer, perhaps what you are referring to as being "gapped". However, I have seen many cell manufacturers, usually cheap ones. that stick the jelly-roll right into the can without any kind of spacer or protection other than the extra separator hanging off the edges of the electrodes.




VidPro said:


> its not rocket science, look how easy they are to dent on the bottom of the actual cell , for example.



Not rocket science, but you need to know what you are doing and have decent equipment. My fear is that people will attempt this with cheap soldering irons, insufficient experience and inadequate respect for the potential safety implications.

I put soldering to lithium-ion batteries in the same category as mixing battery types. There is nothing magic about, and if you really pay attention and know what you are doing, you can do it safely. However, it is best to keep it to yourself 

Be safe VidPro, and please where some kind of eye protection when you are soldering to any kind of battery. 

Cheers,
BG


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## CKOD (Sep 3, 2010)

LuxLuthor said:


> Yeah, I use magic fusion.
> 
> All factory battery packs are spot welded, and the flash weld is so quick, I can immediately touch my finger on top of the weld spot, and perceive no heat. It's like magic.


 
It's definitely nice how there is pracitcally no heat going into the battery top. Put together 2 18650 packs for 2 flashlights I'm assembling and it came out nicer then wiring and solder even with my 80w iron here would have.

Though some of those heavy copper bus bars that RC guys use in their packs look nice and I would consider soldering with paste (or maybe just strips of really fine solder if paste isnt handy) if I needed the low resistance that such a bar would provide. 

Anyone here that assembles pack for their own use put protection PCBs on the pack?


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## VidPro (Sep 3, 2010)

Battery Guy said:


> The bottom of most cylindrical lithium-ion cells has a plastic spacer, perhaps what you are referring to as being "gapped". However, I have seen many cell manufacturers, usually cheap ones. that stick the jelly-roll right into the can without any kind of spacer or protection other than the extra separator hanging off the edges of the electrodes.
> 
> BG


 
And isnt it VERY likly that very high capacity ones that squeeze out every mm of space and even have bigger containers trying to get big numbers , will do exactally that?

There are 2 reasons i dont worry about having the Most capacity one they have today, they could have given up something for the capacity. like longevity or cycle ammount and robustness , or gone out of spec , and just can be damaged easier. by spec , mabey it is just common sence not some actual written law.


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