Lipo question

[paul35]

I've got a 5 cell 18.5 v lipo on my starter, now I've gone to charge it this morning with a bantam bc6 charger and selected 5s 18.5v as the battery but when the charger checks the battery it says it's a 4s 14.8v :/ have I got a knackered battery is the question?

Thanks in advance Paul


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[Mark_T]

Measure the voltage across the discharge wires and see what you get.

Then compare to the voltage on the balance wires.

Should show if one cell has died or if it is a physical problem with a balance wire.

[cjcj1949]

It's worth getting one of those little led voltmeters that plug into the balance socket. Or the voltage alarms that do the same but also give an alrm if a cell goes too low. You can also try an unbalanced charge and check if the volts are what you expect. Try another battery to see if it is the charger or a dirty contact.

[Helimaddan]

It's. Most likely you have drained the pack quite a lot so the charger is only seeing 4s if you don't have a multimeter just put on charger on4s setting for a minute that will wake the cells up disconnect and reconnect it and your charger will prob see all 5 cells now and charge as normal

[paul35]

Sorted put it on a non balanced charge for a while then started a balanced charge now it's seeing it as a 5s

Thanks for the replys


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[cjcj1949]

Try not to let the pack below about 3.7V a cell off load or 3.6V on load. Over discharge is a good way to kill lipos.

[steve g]

are you sure that one of your balance leads haven't come unsoldered iv had this happen it would connect occasionally just check and resolder if needed

[paul35]

Think i may of let it get to low, normally charge it every 6 weeks but must admit its been alot longer this time

[cjcj1949]

Most of us only learn the hard way.

[Raving Jim]

The bantam doesn't like low packs at all, my starter pack hit rock bottom on 2 cells, had to bring it bk to life on a normal charge .

[cjcj1949]

You can bring them back to life on a Bantam, just use a different program. Amps is amps on lipo or NiMh. It's the end of charge that's different. Set a low current on NiMh like 100ma and watch the voltage on each cell. Don't leave the charger. Charge to 3.5V a cell, making sure no cell gets near to 4.2V, then charge at 300ma on lipo balanced until all cells are the same. Some people say that lipos that go below 3.0V shouldn't be recharged as they will be damaged, that's why a good charger won't charge them. You can also charge each cell through the balance lead, if you have only one cell low.