Looking for 48 volt nimh charger kit

[Danny Troy]

This has nothing to do with my r/c stuff, but I have a 48 volt electric bicycle (with brushless motor, or course). The battery charger I had been using just went bad and I'm looking for alternatives. I want to charge the pack, which is made up of 40 "D" cells (10AH cells) as a single unit, so I won't be able to charge two sets of 20 batteries, or four sets of 10 cells separately. Just one large 48 volt pack.

Any ideas on who makes a kit for such a charger, or who sell one at a reasonable price? I need a standard two plug output, not the three pin type, which has a thermistor jack on it.....

Thanks,
Danny

[flatfour]

Is the charger beyond repair or sealed?

What kind of anperage is the stock charger?

For 40 cells, you actually need the charger to go up to approx 58 volts.

[Danny Troy]

I didn't mention it, but I have another of the same charger that is also out of commission. The one that just went bad was a result of attaching the charge leads for an instant with the polarity reversed. I saw a spark and immediately disconnected. Then the next time I plugged the charger in there was an audible pop inside the charger. I managed to pry open the case and I believe one of the parts (capacitors?) in the bottom right exploded in the case. There is evidence of a liquid on that side of the case that probably came from the capacitor. It would be great if someone knowledgeable could point to what part needs replacing.

And yes, as you can see from the specs, it charges up to 56 volts. The output is 1 amp, which gives a nice slow overnight charge.

[Danny Troy]

Update, I just plugged in the charger again and the power light went on, but a few seconds later I heard a sizzling and saw smoke coming from one of the two capacitors on the bottom right of the photo. I immediately unplugged it.
The cap reads: 220uf - 63v - 105 Centigrade

[AndyKunz]

#1 Rule Of Life

When you find yourself in a hole, stop digging!

Don't plug any more chargers in until they are fixed! If that's an output cap, a 63V cap is going to be borderline on a 56V output. They should have designed using a 100V cap.

This (http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P13141-ND) cap might be a suitable replacement.

But if the cap went, there are probably other components gone as well. You should have somebody who is into power supplies (a Ham operator or audiophile?) to help you.

Andy

[wrenwright]

How about an Astroflight 112D?

[AndyKunz]

112D won't go high enough.

Andy

[Danny Troy]

For now I'm biting the bullet and switching over to a better quality, more expensive charger. The new one has some nice improvements, one being a built-in cooling fan....and reverse polarity protection!

I'm holding one to the old units in case I find someone in my area that is knowledgeable enough to figure out what parts need replacing.

Danny