coolrcdad

I used my Indi 16x3 chargers for the first time on my car battery yesterday and had problems getting proper amperage for re-peaking. Despite setting the charger for 5 amps, it would only go as high as about 2.4 amps. Had similar problem with a friend's NiMH batt, charger would only go as high as about 3.5 amps despite being set for 5 amps.

They work fine for regular NiCAD charge.

Anyone else seen this or have any advice? Thanks.

Cole Trickle

When you charge thoose NiMH's, which amp rate do the charger reach? I believe it's 5 amps!

Do your batts get hot, while re-peaking? If so you probably are overcharging them and thereby the internal resistance raise, resulting in lower amps. If this is the case, then simply dont re-peak.

coolrcdad

NiCAD batts weren't hot when re-peaking.
Cold start NiMH mode only got to about 3.5 amps although charger was set for 5 amps.

Cole Trickle

Which brand are yours NiMH-packs? How many packs do you got? Can they take more than 3,5 amps with other chargers?

coolrcdad

I've always been able to charge my NiMHs at 5 amps or more when the charger was plugged into an AC wall outlet. The one I tried when plugged into my car was a friend's. Don't know the brand.

Cole Trickle

Well, you've almost pointed out the solution - the voltage on the car battery are too low.

I dont know the 16x3 manual, but it's a member of a large charger family, and I got a similar version. Your charger can handle 7 cells pack on a car battery pack and 8 cells pack on a 12V DC supply. Depending on the actual voltage on your car battery, this might differ some. Maybe your manual offer some more details.

You might ask what that have to do with a 6 cell pack NiMH. NiMH cells got a larger internal resistance than NiCd's. Therefor they require a higher voltage to obtain a larger amp rate, like 5 amps. It's simply the physics law of Ohm - they are hard (impossible) to get around.