Batteries and charger help please.

[Luckydevil]

So I've got a Hitachi charger and two 14.4v batteries (all used).

Now the first time I plugged a battery into the charger, the charge light lit up for a few seconds and then went out like it was fully charged. The battery was putting out 14.4v (tested on my multimeter) and died within about 15 seconds of drill use. So I plug it back into the charger and now the charge light won't come on for this battery.

I got another battery and the same EXACT thing happened. Charge light lit up when I plugged it in and then went out after a few seconds. Then the battery died very shortly and now won't light up the charge light like the other battery.

I'm going crazy here. Before I drop a nice chunk of change on having two batteries rebuilt and buying a new $60 charger does anyone have any ideas what is wrong?

Do I have two bad batteries or is it the charger? Is there any way to test the charger or batteries?

Thanks guys.

[bmwpower]

I would say the problem lies with the charger. AFAIK, the charger contains the circuitry involved in determining when a charge cycle is complete. If that circuitry goes bad, you see the problem you're seeing. Also, the chance that BOTH batteries are bad is slim...unless of course you left them in subzero temperature for a while. In FL, I doubt it.

[Luckydevil]

I would say the problem lies with the charger. AFAIK, the charger contains the circuitry involved in determining when a charge cycle is complete. If that circuitry goes bad, you see the problem you're seeing. Also, the chance that BOTH batteries are bad is slim...unless of course you left them in subzero temperature for a while. In FL, I doubt it.

I bought the batteries and charger used off of ebay, so I'm not sure about the history behind them. I pulled the circuit board out of the charger to look for anything out of the usual and didn't see anything. I've heard that Nicad batteries can do weird things like this when they go bad, so that was making me think it could possibly be them.

Is there anyway to test the charger with a multimeter?

[bmwpower]

I bought the batteries and charger used off of ebay, so I'm not sure about the history behind them. I pulled the circuit board out of the charger to look for anything out of the usual and didn't see anything. I've heard that Nicad batteries can do weird things like this when they go bad, so that was making me think it could possibly be them.

Is there anyway to test the charger with a multimeter?

Easy test here.

Go to Lowe's and buy a Hitachi charger/set that has the same components in it. Try your batteries in the new charger. If it charges the batteries, you charger is bad. If the batteries don't charge on the new charger, your batteries are shot. Bring the Hitachi set back to Lowe's - no harm.

[Bradley Miller]

Or find a buddy who has one . . . I just ran into this same thing but it was with all my old Versapack crap. I've got a bunch of the tools and they were fine for back when I was in a townhouse and not really using them seriously, but after a few years of non-use (or overcharging I'd guess) the batteries have went south. I've boxed them all up to go to a drop-off for NiCads. (DON'T TRASH THEM GUYS -- I DON'T WANT MY DAUGHTER'S KIDS CHOKING ON BAD GROUND WATER . . . BTW: She's going to be four years old . . . we have a while before that happens. Whew!)

The downfall with multiple battery systems is eventually one of the cells is going to go into reversal and cause the whole shebang to fail. In the RC stuff we'd yank the packs apart and match them up, the closer the match the better the voltage and the closer they were to all going flat at the same time. The key on things is not to let the pack go totally flat. On RC stuff we'd nix on 5.9 volts out of a 7.2 pack. Once the voltage drops below that (5.9/6 = ??) the cells would drop QUICK and the weakest one is going to be zapped with the current flow, eventually causing it to fail.