A123 charge rate? - RC-Monster Forums

nativepaul · **A123 charge rate? -** 02.01.2009, 11:15 AM

Hello to all you A123 users, I just got some A123 cells and have a question about charging them, I have a charger with an A123 program so no problem there but how robust are they, what rate should I charge them at? I know they can take some serious charge currents an not blow up but will high charge currents decrease their longevity or degrade their performance? I will be making up 3s1p packs for maximum flexibility so I can charge 1p at 10A at the moment is this OK or do I need to charge at 1-2C to get a decent lifespan out of them? I need another charger soon and there are a few 20A chargers out now, that sounds great to me as with 2 packs I can charge one in the time it takes to run down the other so I could run almost continuously all day but would 8.7C charging ruin my cells in short order?

JThiessen · 02.01.2009, 01:07 PM

My thought on this is that you are basically asking a question about something that really can't be proven. If your cells die 6 months from now, how would you really know what they died from?

That being said, I would think that if your cells dont overheat while charging, you can charge at the manufactures stated rate and not suffer any ill consequences.

Metallover · 02.01.2009, 01:08 PM

Isn't it supposed to be 5c?

johnrobholmes · 02.01.2009, 01:41 PM

10a is about the most I would push them.

02.02.2009, 04:35 AM

I run 6s1p. And I charge them at 10amp (that is max rate my charger can put out). So far its been 6months and the IR reading on the cells has not change much...but I am not sure if that is a good way to tell if they are degrading or not.

sleebus.jones · 02.02.2009, 10:12 AM

A123's are perfectly safe to charge at 10A. I've been doing that forever now and they are fine.

02.02.2009, 11:19 AM

^^ +1, 10 amps on both the 5S1P and 6S1P pacs I built.

02.02.2009, 10:58 PM

What chargers are you guys running? I've got a Bantam BC8 but it can only do 7A charges. I'd like to do 10A plus, but its interesting trying to find a charger that will do that for 6s and 7s packs.

snellemin · 02.02.2009, 11:20 PM

Fma chargers will do it. Personally I use an old 6s Balance pro charger.

nativepaul · 02.03.2009, 12:06 AM

I use a hyperion 1210, 12s 10A and have been thinking about the new 720 7s 20A

Unsullied_Spy · 02.03.2009, 12:28 AM

There are people that have charged them at 25 amps, but it reduces their run times. A123 actually posted a small chart on another forum showing the expected number of cycles at different charge rates. If I'm not mistaken, 10a should get you at least 500 cycles.

02.03.2009, 12:45 AM

Was just looking at the stats for the 1210 and I'm a little confused.

It says that it's 180W max. So for example, could it charge my 7s A123 packs at 10A? Because ( [3.3v x 7] x 10 = 231W) which is obviously over the max output.

Or is it because, when it starts charging, assuming the pack is flat, the voltage would be lower (around 15v if the pack is dead), and so it can charge at the full 10A then, and as the voltage of the pack increase, the charger would decrease the output etc?

Picking chargers has always confused me lol :D Thanks for any help

Unsullied_Spy · 02.03.2009, 12:50 AM

Quote:

Originally Posted by cdis

Was just looking at the stats for the 1210 and I'm a little confused.

It says that it's 180W max. So for example, could it charge my 7s A123 packs at 10A? Because ( [3.3v x 7] x 10 = 231W) which is obviously over the max output.

Or is it because, when it starts charging, assuming the pack is flat, the voltage would be lower (around 15v if the pack is dead), and so it can charge at the full 10A then, and as the voltage of the pack increase, the charger would decrease the output etc?

Picking chargers has always confused me lol :D Thanks for any help

You'll get about 7.8A charge rate when that pack is depleted, and it'll drop to 6.9A or so by the end.

02.03.2009, 01:18 AM

Ouch. Well, I should mention that my 7s packs are made up of a 4s and 3s in series. So I guess I can charge them separately at the 10A rate and put them together, which is what I've been doing currently. Just wanted to see if there actually was a charger that was capable of charging the 7s packs at around 10A.

While I'm on the subject, I don't suppose there's any way to connect the balance taps of the 3s and 4s packs together so that if I decide to charge them as a 7s pack, I can balance at the same time?

I suppose I'd have to be very careful as to which way I plug the 4s and 3s packs into the series connector so that the balance connectors are also correct, but it should be possible right?

Unsullied_Spy · 02.03.2009, 01:30 AM

It's possible to do that. Hobbycity sells adapters for that. You have a 1210i though, you could do what I did and get 2 of the LBA10 balancers and the networking kit. I can charge my 2 2s lipos at a time on my 5i. It's slow but easier IMO.