Bad batteries

Has anyone been having problems with battery packs? Specifically the A123 LiFEPO4. I got my packs a couple of weeks ago and hadn't touched them until I decided to cycle them today. When I got them they both read 16.5 volts but now one of them says 11. Then when I tried to do a slow charge (.25 amps) it only detects 4 out of the 5 cells. I realize it detects the number of cells by voltage but how do I charge it back up and keep it working?

SenaiERI

Never mind. I figured it out.

I did a trickle charge ( charge at .25 amps) and left it for a couple hours. When I left it last night it read 16.2 volts and this morning it reads 16.29, so it accepted the charge and is holding it steady.

IT'S SAVED!!!!!

SenaiERI

just make sure you're balancing your cells. If they charge out of balance enough, they could do bad things... *cough*explode*cough*

I was helping eddie with his a123 packs last night and I learned a bunch of stuff...

ummm. on a 5 cell A123 pack it should be reading around 16.8 - 17 volts fully charged... I don't think you have saved anything...

I know I have told you this before Senai but you ALWAYS charge A123's at 5 amps! ALWAYS, ALWAYS, ALWAYS.

MattTavares wrote:

ummm. on a 5 cell A123 pack it should be reading around 16.8 - 17 volts fully charged... I don't think you have saved anything...

I know I have told you this before Senai but you ALWAYS charge A123's at 5 amps! ALWAYS, ALWAYS, ALWAYS.

I realize they need to charged at 5 amps. It even says so on the charger. But neither of my packs has peaked because I am afraid that charging them at less than 1 amp will hurt them.

Correction: Batteries now read 16.5 and 16.76.

SenaiERI

SenaiERI wrote:

MattTavares wrote:

ummm. on a 5 cell A123 pack it should be reading around 16.8 - 17 volts fully charged... I don't think you have saved anything...

I know I have told you this before Senai but you ALWAYS charge A123's at 5 amps! ALWAYS, ALWAYS, ALWAYS.

I realize they need to charged at 5 amps. It even says so on the charger. But neither of my packs has peaked because I am afraid that charging them at less than 1 amp will hurt them.

Correction: Batteries now read 16.5 and 16.76.

SenaiERI

What? that didn't make any sense. Why are your fears affecting your battery's ability to peak? I need to know the following things.

What amperage are you charging the batteries at and what voltage and amperage are you supplying the chargers with?

what charger are you using??

we charge K2's using the astroflight A123 and packs charge up to 18v...then drop to around 17.xx

And the K2's are 3.2 v cells (nominal)

yeah, he is using those same chargers