# Turnigy Accucell-6 problems



## sailah (Mar 23, 2010)

So I recently got a Turnigy Accucell-6 hobby charger to complement my Ultrafire 139.

Here's the problem, I used the LiPo charge setting to charge a single Ultrafire 18650 2400mah cell. I checked the voltage at start and it was 4.10v. when the charger signaled it was finished I checked the voltage and it read 4.14v.

Huh. So I tried it again. Kicked off again, and was "reading" 4.20V as the finished voltage. I tried another 18650. Same thing, kicked off at 4.14V, verified by my voltmeter(s).

I then calibrated it, and during the calibrating setting it was right on in reading the cell voltage at 4.14V.

I tried charging both cells in 2S mode, kicked off at "8.4v" but each cell read 4.14V. Checked them with 2 different DVM, same thing.

I then tried to "trick" the charger by under-calibrating it and it charged to 4.15v.

So I put both cells in the Ultrafire W-139 charger and it topped them both off to 4.20V at the end of the charge read by both of my DVM.

Is it acceptable for the charger to go to 4.14V? Seems like I am not getting a full charge or is this where I would ideally like to charge to to maintain my cells in tip top shape? 

I don't feel like shipping this back to Hong Kong and it seems to be working fine. Any thoughts?


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## 45/70 (Mar 23, 2010)

Hi sailah.

What charge rate were you charging the cells at?

A hobby charger will terminate the charge when the charge current, during the CV stage, drops to somewhere between 0.03C and 0.1C (where C=the charge rate).

The faster the charge rate used, the longer the CV stage will take. The slower the charge rate used, the shorter the CV stage will be. So, when a faster charge rate, eg. 1C is used, the charge will result in a long CV stage. When a slower charge rate, eg. 0.5C is used, the CV stage will be shorter. The shorter the CV stage, the higher the ending OC voltage of the cell will be, as it will receive more of the charge during the CC stage.

Also, the higher the charge termination current, the lower the ending OC voltage will be. So if your charger terminates at 0.1C, the cell will be at a lower voltage than when using a charger that terminates at 0.03C.



sailah said:


> I tried charging both cells in 2S mode, kicked off at "8.4v" but each cell read 4.14V. Checked them with 2 different DVM, same thing.



I seriously hope you were using balancing leads when you did this!  If not, you run the risk of running into serous problems, as in ! Without balancing leads, the charger has no way of knowing what the voltage is of an individual cell in the string. While not guaranteed, this can result in grossly overcharging a cell and result in an explosion!

 *Don't charge Li-Ion cells in series without using balancing leads* 

Hope this helps.

Dave


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## sailah (Mar 23, 2010)

Dave,

I think you may be on to something...

I was charging the 2400mah cells at 2.4A or 1C correct? Should I lower that down to 0.5C or 1.2A?

I do know about the balancing leads as I have some on order. I only charged them for about 20 seconds and it kicked off saying they were full anyways.

I may discharge the 18650's and charge at a much slower rate and see if I can get the voltage higher. Thanks for the tips.

Peter


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## 45/70 (Mar 23, 2010)

It's worth a try, Peter. I think you will find that the cells will come off with a somewhat higher OC voltage. My Dynam Supermate DC6 typically charges cells to 4.16 Volts (OC) when charged at 0.5C. I can't remember exactly, but at slower rates, the cells come off a bit higher and at higher rates a bit lower.

The reason your WF-139 charges to 4.20 Volts, is that it is a CC only charger. Bad for the cells, but I suppose it does more completely charge cells. :sick2:

One thing I forgot to mention,



sailah said:


> ......Is it acceptable for the charger to go to 4.14V? Seems like I am not getting a full charge or _*is this where I would ideally like to charge to to maintain my cells in tip top shape*_?



If you're not going to use your cells for a while, or are going to store them, you want to charge/discharge them to about 3.80-3.85 Volts. At this voltage (about 40% SOC) the least amount of oxidation will occur within the cell. Storing Li-Ion cells at either very low SOC or very high SOC promotes internal oxidation of the cell. In addition, I keep my unused cells in the fridge. This alone can reduce degradation of the cells by up to 70%. 

*EDIT:* I should have mentioned, that by only charging your cells to ~4.10 Volts (as in using the "LiIo" setting), you can extend the number of complete cycles from 300 to as much as 1000. The only drawback is that the cells will only be about 90% charged.

Dave


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## VidPro (Mar 23, 2010)

acceptable sure. nessisary for that charger to do so? i donno.
but i can run a test here, i never thought about it because 4.20 (+- .05) is close enough 

what Wires are you using to connect?
it keeps dropping down in current near the end as it should, then finnaly terminates, trying to reach 4.20. Hmm why it is everyone is so obsessed with 4:20 anyways :thinking: 
I dont think it PAUSES to check a battery voltage, so the wire type and length would probably make some of the difference, the voltage it is using/seeing is both the charge and the battery.
and there is no *very* slow final topping stuff at very low currents, But i think there is in Balancing a set.

at the first of the charge it just jams the set current in, but doesnt voltage over 4.20
when the cell reaches higher voltages the rate goes down (continually)
and its reading mostly the battery voltage, when the rate drops, but the charge still exists slightly. (so you SEE 4.20 but the battery itself isnt there yet)
(geesh how do i say that right)
Terminate is done when the current goes low, and the voltage was being KEPT at/below 4.20 *via current control*. when the battery goes back to resting, it should read about what your saying. 

sounds like a proper CC to CV , then when C goes below i think about 50-100ma it bails. (in standard charge modes)

so in engrish, it does Constant Current (CC) (voltage hasnt reached 4.2 so current set by user is used).
When the battery is reading high voltage (actually at that current) the current keeps going down , 
Once the current drops it is Basically having CV Constant voltage, current keeps dropping.
once current goes below some set ammount , at the (psudo) CV it then terminates.

Other chargers are Lock down connected, neer 0 Ohms resistance between battery and charge curcuit stuff, and will taper down much slower, and "top" off for a bit longer. have a lower Current value before terminations.
like your Fired charger probably never has a voltage above ~5 , and it does a psudo CC CV thing too, but slower and ends slower. 

geez i think i finnaly said it right.
Freak that, it just keep lowering the current to keep it under the voltage. It is a digital current controlled "Max Voltage" , at a SET "Max Current" type alogrythm. you can do basically the same thing with a bench power supply.


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## sailah (Mar 24, 2010)

So I tried the lower current method. Put both batteries in my M1X for 30 minutes to draw them down.

I have one on the Turnigy charger at 0.5A and it's been on there 45 minutes, 330mah added. Funny, the battery is COLD. When they used to charge in the Ultrafire, they were def warm.

I checked the voltage and it's at 4.18V and the charger isn't done yet. So I guess that's the answer. Glad I asked and glad you guys know way more about this stuff than I.

I'm not obsessed over the 4.20 now, but about 10 years ago i sure as hell was.:ironic:

Aside from not understanding how the whole charging thing works, I am mightily impressed with this Turnigy from Hobbycity. I scrapped a power supply from an old computer and it works great. esp since I just bought every size LiPo battery known to man, I'm glad I have a universal charger. Can't wait to build my balancing leads and a custom charging cradle.

Thanks for the helplovecpf


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## Mr Happy (Mar 24, 2010)

Where are you guys getting your Accucel-6's from? I've been looking on the HobbyKing web site and it's been showing out of stock for weeks now...?


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## jasonck08 (Mar 24, 2010)

I got mine from them like a year ago. I bought it from hobbycitys US warehouse... The voltage of mine is a little off. Charging termination is typically at around 4.15-4.17 not that bad. But when I discharge batteries its off by about .05v. Is there an online manual where you can calibrate this thing???


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## VidPro (Mar 24, 2010)

Mr Happy said:


> Where are you guys getting your Accucel-6's from? I've been looking on the HobbyKing web site and it's been showing out of stock for weeks now...?


 
there is a new better one.
mabey they even fixed the worthless fan 

if i tossed more money into one, i would want Much Faster Discharge, the machine doing balancing is Coool.


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## VidPro (Mar 24, 2010)

i finish test, same thing, it finished at ~4.22 Charge *&* Battery voltage. then of course (old) battery went down to ~4.13v after that.
I have very short copper speaker wires going to strong magnet connection going at the time. (obviously didnt help)

set to lower current, and like you said it keeps plugging away. yaawwwn
after it slowly kept topping with this lower current rate battery read about ~4.18


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## 45/70 (Mar 24, 2010)

I just charged an AW 10440 on my Supermate. It's about 2 years old (one of the older blue wrapper 320mAh ones), but has mostly been stored in the fridge @ ~3.80 Volts and 35-40F. I charged it @ 100mA and the OC voltage was 4.18 Volts. I think the OC voltage readings of charged cells will vary a bit depending on the size of the cell, how old it is and it's general condition.



VidPro said:


> ......why it is everyone is so obsessed with 4:20 anyways



One reason that I like to have the capability to charge cells to 4.20 Volts is it's a lot more accurate when determining the health of LiCo cells. If you can't charge them up to 4.20 Volts, you have to extrapolate a bit. I use other chargers for this purpose, like the YOHO-122 for example. It almost always will charge cells to 4.20 Volts, but occasionally to 4.21 Volts.

Dave


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## VidPro (Mar 24, 2010)

hmm, i usually use this thing for balancing actual packs, which seems to take a long time. long enough that . . . but i think i should check that better too now.


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## VidPro (Mar 24, 2010)

balance 5000ma 14.4v pack, inital current 1.6amp
final resting voltages ~4.17 , variation +-.01 (meter accuracy .01 
correction, the variation across cells was .02 without the +- 
meaning it looks like this 4.18 4.17 4.16 4.17

lowered the current to .1amp yaaawwn, let it play with it for a hour
about same variation seen, teeney bit higher voltages
looks like this now 4.19 4.17 4.17 4.18
that was a waste of time


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## sailah (Mar 24, 2010)

Mr Happy said:


> Where are you guys getting your Accucel-6's from? I've been looking on the HobbyKing web site and it's been showing out of stock for weeks now...?



I put myself on the email list and got an email probably about 2 weeks ago and ordered one right away. Got it yesterday.


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## sailah (Mar 24, 2010)

jasonck08 said:


> I got mine from them like a year ago. I bought it from hobbycitys US warehouse... The voltage of mine is a little off. Charging termination is typically at around 4.15-4.17 not that bad. But when I discharge batteries its off by about .05v. Is there an online manual where you can calibrate this thing???



Jason,

If you unplug it, hold down the start & negative buttons, replug it in, it will start flashing. Put a known battery voltage to the leads and adjust the voltage from there. I've heard that it only calibrates the screen voltage. Here's a link to youtube.

http://www.youtube.com/watch?v=9hvR7dGAkEo


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## tx101 (Mar 24, 2010)

Mr Happy said:


> Where are you guys getting your Accucel-6's from? I've been looking on the HobbyKing web site and it's been showing out of stock for weeks now...?




I ordered my one three weeks ago and have just received a email that it has
shipped

Sorry for going OT


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## NutSAK (Mar 24, 2010)

VidPro said:


> Hmm why it is everyone is so obsessed with 4:20 anyways :thinking:



Because it's the best time of the day?

I'm satisfied with the 4.18V final voltage I get from my Accucel-6 when using a .7C charge rate. I have verified that mine always holds a steady 4.20 volts across the cell (charging voltage) during the CV stage. Sailah, that is something that you might want to measure.


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## Black Rose (Mar 24, 2010)

VidPro said:


> there is a new better one.


And that would be?


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## sailah (Mar 24, 2010)

So one more quick question...

I'm discharging a fully charged 18650 Ultrafire. What I want to know is the capacity vs the claimed capacity. I am discharging at 1A. How do I calculate the capacity? My charger has a timer on it, as well as voltage (started at 4.17V and will terminate at 3.00V) and a climbing number which I assume is mah. Is this correct for determining capacity or do I need to do math?

Thanks guys


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## VidPro (Mar 24, 2010)

Black Rose said:


> And that would be?


 
i dont know, HobbyKing was e-mailing me about it (another turnigy).
also check thunder6 AC , connects to computer has software, runs on AC ($55 amazon and hobby places)
also the supermate AC , if you want EU plug . (same interface look style) like 45/70 said

still didnt see (cheap) one that does better than 1A discharge. The 50W max charge works for enough stuff.
some of them dont bother with 40mm fans that scream and die early  (passive sync)


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## VidPro (Mar 24, 2010)

sailah said:


> So one more quick question...
> 
> I'm discharging a fully charged 18650 Ultrafire. What I want to know is the capacity vs the claimed capacity. I am discharging at 1A. How do I calculate the capacity? My charger has a timer on it, as well as voltage (started at 4.17V and will terminate at 3.00V) and a climbing number which I assume is mah. Is this correct for determining capacity or do I need to do math?
> 
> Thanks guys


 
Its close enough for comparison. if your trying to determine the Capacity , The number you read when DISCHARGING is what the battery held. The number shown when charging is what was sent towards the batterys general direction, and does not mean it held that power.

if you want to compare to what the overrated manufacture did, then you gotta go solid full 4.2V , and drop it as low as 2.6V (say) but they dont like to be so low. then what RATE of discharge is important too.
EX: say you have a 2400UF thing , to try and get close to thier rating, charge it fully 4.2 (4.25 even) , discharge it slowly all the way to a very low cut-off.

When you see other charts and graphs, and discharge specs on forums and stuff, you just apply thier SAME methodology to compare to thier testing. everyone tests a bit different, It is the SPECS of thier testing that is important for comparison.

the only real way to compare to a manufactures specs for SURE , is to read exactally HOW the manufacter aquired that fantasy capacity, and look at what THEY do in thier spec sheet , and follow it exactally the same. Sure there is standards, but the spec sheet that shows capacity also attempts to show the testing parmeters.

3.0 is a good place to stop, treat battery well, what is left is little and depends on the battery, and battery resistance ETC. so no real problem exists.
The capacity YOU will get out of any battery is all that maters right? so YOUR test, should attempt to simulate YOUR use and charging patterns, YOUR parameters are what you will have when using it.
if you want to display your testing, simple JUST provide the parameters you used when you show results of the test. We get that 

charge level was ??? 
discharge rate was ??? 
Device used was ??? 
Stop discharge at ??? 
, i get ??? capacity. 
Is lots of information.

Tested got ??? capacity is NO information


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## sailah (Mar 24, 2010)

Cell: Ultrafire 2400mah "grey" 18650
Starting voltage: 4.17V (measured with DMM)
Ending Voltage: 3.68 (Measured with DMM)
Discharge current: 1A
Time:120 min (default, stopped right on the money, I changed this to go unlimited time and default voltage stop now is 3.00V)
Counter:1999
Charger: Accucell-6

Recharging the cell now at 1 A


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## VidPro (Mar 24, 2010)

Cheap trix.
if you want to take a li-ion or li-poly TOO LOW (or just lower) go to ni-mhy discharge and set your own Voltage. the device doesnt know its lithium and will blindly discharge it very similar to the other discharge but lower. 
(but remember they dont wanna be that low)
and it wasnt designed to work that way, and dont charge that way, and its not right, it just is a cheap trix


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## zer0ne (Mar 25, 2010)

Mr Happy said:


> Where are you guys getting your Accucel-6's from? I've been looking on the HobbyKing web site and it's been showing out of stock for weeks now...?


As of the time I am typing, Hobbyking has restock it...left 200ish pieces left.


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## BigHonu (Mar 25, 2010)

NutSAK said:


> Because it's the best time of the day?
> 
> I'm satisfied with the 4.18V final voltage I get from my Accucel-6 when using a .7C charge rate. I have verified that mine always holds a steady 4.20 volts across the cell (charging voltage) during the CV stage. Sailah, that is something that you might want to measure.



Same here.
I charge at .77C and end up at 4.19 - 4.20V consistently. CV stage takes about 45 minutes or so. Batteries stay nice and cool throughout the charge.


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## Linger (Apr 17, 2010)

With UF130 use I'd tried to never charge above 4.1 just for cell longevity.
Last night I let the Accucell - 6 run on a cell I knew I was going to discharge right away, it took a 14500 @.4a to 4.15v before I stopped it.

Sailah, I was reading more on this charger and many rc people advocate long slow charges for max battery longevity. They may push the C rates to 5 or 10 'on the field' when they're out doing whatever RC people do, but suggest when you have time to use low rates and overnight charges.

/OT
Ordering Turnigy Accucell - 6
Place an order, reguardless of stock level. I'd watched it for months before pulling the trigger. When I ordered stock read -360units and HK caution was it may be a month before inventory arrives. Then email said shipping could be up to 45 days.
I had the sleek unit *gripped firmly in my hand less then 3wks* after ordering. And they included a cord for the power supply that websight states isn't included, so entire unit was GTG right outa the box and I was charging minutes after arrival. Totally won me over for HK service.


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## jasonck08 (Apr 17, 2010)

I've done some further testing with my charger. It was terminating at 4.14-4.17v typically.

I calibrated it and set it to about +15 or something, so now it will charge up most cells to 4.2v.

I find that if I have the charger set at a higher current like 1 or 2A, the charger doesn't stop at 4.2v as accurately as if I set the charging current to .1A.

A lot of times to get batteries to the right voltage, I'll start them off at somewhere around .7C, and then the charge will terminate at 4.18v or so. Then I'll top them off at .1A and it will usually complete the charge at 4.2v.


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## guner7 (Feb 23, 2013)

Hi, sorry to dig up the old thread.

I read the whole thread and be able to understand a bit about the charging philosophy..
Say I am going to charge a 4000mah 18650 with my Acc6, so the ideal setting of the current would be 0.7C or 2.8A?
What if I need to charge 2 cells in parallel, is double the current is what I need after all which would be 5.6A?

I appreciate for all inputs, thanks.


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## Mr Happy (Feb 23, 2013)

guner7 said:


> Hi, sorry to dig up the old thread.
> 
> I read the whole thread and be able to understand a bit about the charging philosophy..
> Say I am going to charge a 4000mah 18650 with my Acc6,



Where did you obtain this remarkable item? A typical 18650 lithium ion cell will have a capacity around 2600 mAh. You should assume the 4000 mAh claim to be "optimistic". It's always best to measure these things and not take marketing claims for granted.




> so the ideal setting of the current would be 0.7C or 2.8A?



No!! 

If the cell already has a dodgy label on it you don't know how it will stand up to a high charge rate, especially one that could over 1C in this case. Be safe and dial it down.

Unless you have a genuine cell from a big name manufacturer like Panasonic or Sony where the datasheet says otherwise, I would not recommend to charge an 18650 at a current higher than 1 A.



> What if I need to charge 2 cells in parallel, is double the current is what I need after all which would be 5.6A?
> 
> I appreciate for all inputs, thanks.



If you put two cells in parallel then you could double the current to 2 A.


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## guner7 (Feb 23, 2013)

Mr Happy said:


> Where did you obtain this remarkable item? A typical 18650 lithium ion cell will have a capacity around 2600 mAh. You should assume the 4000 mAh claim to be "optimistic". It's always best to measure these things and not take marketing claims for granted.



Ah yes, I probably being too naive to be deceived by its chinese label..:shakehead






Thanks for the heads up!!
I will charge it not more than 1A then..

One question though: Assume the battery holds the capacity as it claimed. Will the battery have the full capacity after the charging is complete, with the 1A setting?


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## Mr Happy (Feb 23, 2013)

guner7 said:


> One question though: Assume the battery holds the capacity as it claimed. Will the battery have the full capacity after the charging is complete, with the 1A setting?



Yes. With lithium ion cells the lower the charge rate, the fuller the charge.


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## guner7 (Feb 24, 2013)

Mr Happy said:


> Yes. With lithium ion cells the lower the charge rate, the fuller the charge.



This is loud and clear, thank you Mr Happy.:thumbsup:

Am I correct if I'm assuming to charge 6 Lipo 2S-1500mah in parallel with Acc6 is feasible despite the max current of the charger is 6A, all Lipo will have fully charge after the charge cycle is complete. It just the time to take to complete the charge would be longer than if I use the 10A charger, correct if I am wrong. 

I get confused after heard one pointed out that I need to restart my Acc6 after the first cycle charge is finish because it was only 6A that pump into the batteries and I still short for another 3A from the total mah of this setup so I need another charge cycle for that reason.

Sorry to question alot..
I just don't want to spend money for another charger if I don't have to.


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## Mr Happy (Feb 24, 2013)

Yes, if you use a lower charge current the charge just takes longer to complete. But the battery will still be fully charged as long as the charger does not reach the programmed time limit first.

You mentioned charging 6 batteries in parallel. Although this might work OK it is not recommended to charge so many batteries in parallel at once like that. It is best to limit it to only two or three in parallel at one time. But if you have the right balancing harness you could charge three batteries in series. As long as you connect up the balancing wires correctly the charger will keep the three batteries balanced during the charge.


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## jasonck08 (Feb 24, 2013)

guner7 said:


> One question though: Assume the battery holds the capacity as it claimed. Will the battery have the full capacity after the charging is complete, with the 1A setting?



Don't assume anything about Ultrafire cells other than they are junk. There is not a cell on the market over 3400mAh....


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## guner7 (Feb 24, 2013)

Once again thank you Mr Happy your replied are greatly cease my doubts. 



jasonck08 said:


> Don't assume anything about Ultrafire cells other than they are junk. There is not a cell on the market over 3400mAh....



Thanks for the fact Jason. 
I guess I am picking up Panasonic 2900mah after some googling.

Glad I'd stop by at the right place. 
Appreciate for all the helpful insights.:twothumbs


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## Nisei (Jun 7, 2015)

Sorry to bring back this old topic but I think it's better to keep all information in 1 topic than starting a new one.



jasonck08 said:


> I've done some further testing with my charger. It was terminating at 4.14-4.17v typically.
> I calibrated it and set it to about +15 or something, so now it will charge up most cells to 4.2v.
> I find that if I have the charger set at a higher current like 1 or 2A, the charger doesn't stop at 4.2v as accurately as if I set the charging current to .1A.
> A lot of times to get batteries to the right voltage, I'll start them off at somewhere around .7C, and then the charge will terminate at 4.18v or so. Then I'll top them off at .1A and it will usually complete the charge at 4.2v.


This doesn't make sense to me.
Your batteries were coming off the charger reading a bit low (4.14-4.17 instead of 4.20)
You say you've calibrated it by setting it to +15? But that would mean it was reading low compared to your multimeter...
If it was reading too low and you've adjusted for that, it would mean they would now come off the charger even lower than before.


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