A123 battery back from the dead - what to watch for?

[FLYINCHASE]

Great info Jeff. or just buy a new pack from you....... WAAAAAA That's what I wound do. Not worth gambling on a plane for the price of your great packs

Thanks
Mike

[grosbeak]

Best thing to do when you have a questionable A123 or LiFe pack is to charge/discharge each cell individually. Because the voltage (and discharge curve) of the pack is so flat - most chargers have a hard time balance charging these packs when the cells are really far out of balance. Because of this you will have a hard time discharging and charging a pack that is severally out of balance (it will also be hard for you to tell that a pack is severally out of balance)

You can easily charge each cell by making individual cell charge harnesses using JST extensions (you just cut the one wire for the second cell on each harness - so you have a right side cell harness and a left side cell harness). This way you can use the regular charge/discharge feature and focus on one cell at a time. Working with one cell at time takes the "balancing" variability out of trying to determine if you have a problem.

Thanks for the tips, Jeff. I have the extra leads - would I still use the standard charge lead? And would I set the charger to 1S?

Great info Jeff. or just buy a new pack from you....... WAAAAAA That's what I wound do. Not worth gambling on a plane for the price of your great packs

Thanks
Mike

Yep - and if you look back at post #9 you'll see that's exactly what I did.

[Ramjet]

Best thing to do when you have a questionable A123 or LiFe pack is to charge/discharge each cell individually. Because the voltage (and discharge curve) of the pack is so flat - most chargers have a hard time balance charging these packs when the cells are really far out of balance. Because of this you will have a hard time discharging and charging a pack that is severally out of balance (it will also be hard for you to tell that a pack is severally out of balance)

You can easily charge each cell by making individual cell charge harnesses using JST extensions (you just cut the one wire for the second cell on each harness - so you have a right side cell harness and a left side cell harness). This way you can use the regular charge/discharge feature and focus on one cell at a time. Working with one cell at time takes the "balancing" variability out of trying to determine if you have a problem.

balance feature is only 200mah in most chargers . so if you have a badly out of balance battery and you charge or discharge at anything over 200mah the balance function can not keep up to the rate of charge or discharge , the high cell when charging will peak and shut down the charger early before allowing the low cell to fully charge (same thing will happen when discharging) . simple fix is to charge or discharge @ 200mah or less on a out of balance pack to bring it back.

the balance feature is just a load applied to the highest cell and in most cases is a constant rate of 200mah. if you charge @ 200 mah and the load is 200mah the charger can stop the charge to the high cell until the low cell is fully charged. granted this takes forever but it does work .