Turnigy Accucell-6 problems

[VidPro]

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

 

[sailah]

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

 

[VidPro]

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

 

[zer0ne]

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.

 

[BigHonu]

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.

 

[Linger]

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.

 

[jasonck08]

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.

 

[guner7]

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.

 

[Mr Happy]

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.

 

[guner7]

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?

 

[Mr Happy]

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.

 

[guner7]

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.

 

[Mr Happy]

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.

 

[jasonck08]

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....

 

[guner7]

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

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

 

[Nisei]

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.

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.