A123 charging problem - Page 2 - RC-Monster Forums

Arct1k · 01:25 PM

IIRC it is a 2mm Bullet in the middle...

I would make a custom deals harness - i.e. create a short deans extension lead male to female deans. The wire the hyperion tap into the deans extension - red to red, furthest from black to back deans and the middle back to the 2mm bullet.

I think I'd be inclined to get that pack back up now by hacking together a direct charge lead for the dodgy cell - i.e. 3mm bullet lead off the centre of the pack and a single wire to a male deans either on the red or black side depending on which cell is 0v. I'd then just use the NiMH mode at .2 amps to get the voltage up...

Or just do as Jeff said .2-.5 amps across the whole pack to the volatge up...

JThiessen · 02:28 PM

Quote:

Originally Posted by jhautz

Set your charger to NiMH and a very low current setting like 0.5 amps and hook the pack to the charger for just a few minutes so you can raise them above 4v. then stop the charge and set the charger to a proper a123 charge cycle, but if you can set the current very low (like 0.5v again) and charge them like that. You should be able to get them back up to full voltage but it will take a few hours to get them there.

Be careful when doing this initial bump charge with the NiMH setting and don't forget and leave them on there. It shouldn't take much at all to bump them back over the 4v minimum so your charger will recognize them properly.

Once you start feeling the power drop off noticeably stop running them. Discharging them to that low repeatedly will certainly effect the life of the cells.

Ok, I got all my packs rewired with Hyp. balance taps, and put one of the bad ones on the charger on Nimh setting, 0.5 Amp, but had to put it on 4.8V (it wouldnt let me set it to 6.6V). It started at 3.18V, and after two plus hours, it got up to 3.43V, but I had to shut it off (bed time!) - now this morning, I've had it back on for 1.5 hours, and they are only back up to 3.3X volts so far. It seems to be taking much longer than was stated above. I do have the balancer plugged in, but that also put some quirks in the process. The first time it scrolled through asking how many cells. I waited until it said 2 and pressed enter. It charged for a bit, then gave me a "low output voltage" error. So I re-did the connection, set it to 4S, and it seemed to like that setting. Does this sound right? I just wanted to bounce this off those of you who have done this, to make sure its going correctly.

I'm also curious, why set it to Nimh for the intial bump instead of A123?

JThiessen · 07.28.2008, 07:55 PM

I managed to get one of them to 4 volts. I then disconnected it, changed to A123 6.6 4600 mode, then connected the battery mains, then the balancer. It gave me an "Output Battery COnnect Error", and I then tried it without the balancer and recieved the same message. I then stuck a "good" pack on, and it works fine. So I wonder if I need to go higher than 4 volts?

Arct1k · 07.28.2008, 08:22 PM

Can you not rig something just to charge the one pair of bad cells - That would save you over charging the one set.

JThiessen · 07.28.2008, 09:15 PM

I dont know - guess I can try. The Duo wont let me connect the balancer with such a low voltage reading. And it appears the max they will charge to is about 3.57 volts.

I have never assembled or taken any type of pack apart. So....not sure. guess I dont have much to loose.

tc3_racer_001 · 07.28.2008, 09:40 PM

also, the charger has protection which wont charge any damaged batteries, so perhaps this is the issue???

Arct1k · 07.28.2008, 09:58 PM

You'd don'y have to take it apart - Charge using the balance taps...

JThiessen · 10:24 PM

Quote:

Originally Posted by Arct1k

You'd don'y have to take it apart - Charge using the balance taps...

Tried that...no go.....unless there is some trick to make it charge only one cell.....

JThiessen · 07.28.2008, 10:23 PM

Quote:

Originally Posted by tc3_racer_001

also, the charger has protection which wont charge any damaged batteries, so perhaps this is the issue???

I think that is what the charger is seeing. It thinks its a single cell (3.3V). I have one on the charger right now on Nimh at 1.0A, with the balancer connected, but after 45 minutes, its still only at 3.5V.

tc3_racer_001 · 07.28.2008, 11:45 PM

perhpas try running it again??? just a suggestion. looks stuffed tho :(

jhautz · 07.29.2008, 03:34 AM

Do you have a volt meter to check what the voltage of each cell is at the balance tap? If one cell is totally dead and not taking a charge any more your effort is futile.

lincpimp · 07.29.2008, 04:29 AM

Not that this will help much, but I did find something interesting with my hyperion 5i chargers. They will attempt to repair packs that go below 3v per cell.

I over discharged an orion 3200 pack, down to 5.5v. The charger fired up and trickled out a low amp charge until the voltage came up and then charged normally.

I have also put single cells on these chargers that were under 2volts, and the charger has charged them up too. Same low amp start, until the voltage gets up a bit. Low amp charging takes a long time, sometimes days...

JThiessen · 07.29.2008, 03:10 PM

Quote:

Originally Posted by lincpimp

Not that this will help much, but I did find something interesting with my hyperion 5i chargers. They will attempt to repair packs that go below 3v per cell.

I over discharged an orion 3200 pack, down to 5.5v. The charger fired up and trickled out a low amp charge until the voltage came up and then charged normally.

I have also put single cells on these chargers that were under 2volts, and the charger has charged them up too. Same low amp start, until the voltage gets up a bit. Low amp charging takes a long time, sometimes days...

I think it was trying to do this. After about an hour on the charger, it would stop charging and gave a reading of "end flat check" or something like that.