Help troubleshooting battery/charger

"Cam" wrote

The charger probably recognizes the battery's voltage is too low to charge.

Do you have some other batteries around that you could cobble together, to make a pack to test the charging ability of the charger? The batteries do not have to be the same size as the problem battery, to test the charger; just known to be good batteries, and the same total voltage.

Its dead. It should generate something at least to sense the battery.

Probably blown an internal fuse due to being connected backwards or something.

When battery is connected to charger, the only voltage

Almost definitely a fuse in the output then, or a broken wire.

Borrow a charger that is known to work, first. If you have a helpful LHS or club try leaving the battery with someone else to charge.

So that's one vote for the battery and one for the charger. I'll disassemble the charger and look for a replaceable fuse (I don't know anyone else who might have a charger for this pack). If that's inconclusive, I probably have enough NiMH AA's around the house to make 12V, so will try the charge test.

How smart would this charger be (it looks like a cheap li'l thing)? Should I expect the charger to show voltage across the open terminals, or would it have logic to detect a battery before the charge voltage appears? I guess if it's actively controlling charge instead of just supplying current it would be smart enough to know the difference between "battery" and "no battery." Which means the battery voltage could be low enough that it thinks "no battery" and so doesn't switch on any voltage, which would point to a bad battery. But I can't say the battery is bad until I know the charger is good....

Y'all have given me a plan and officially un-stuck me; thanks for the prompt and helpful advice!

Cam

Normally the charger for nickel is current limited..on open circuit it should show full voltage - for a 12 cell pack well over 18v.

On fast charge it would be dumping several amps in, and monitoring the voltage..when the voltage starts to go DOWN it would revert to trickle mode - proabably around 50mA or so.

If its designed to work off a 12v supply, it will have a voltage inverter circuit in it. If that goes the whole charger will be dead as well, so it could be anything.

| So that's one vote for the battery and one for the charger. I'll | disassemble the charger and look for a replaceable fuse (I don't know | anyone else who might have a charger for this pack).

Any decent peak R/C charger should be able to do it -- you might just need to cobble together a plug.

Well, some R/C chargers peter out at 8 cells -- since you have ten, they can't charge it, but even an 8 cell model ought to be able to charge it a little, at least enough to get above the 0.3 volt stage, up to 11 volts or so.

Really, 0.3 volts from a 10 cell pack is a bad sign -- even if it's been sitting for a long time. Unless you're measuring it with something that puts a lot more load on it than a voltmeter?