old nicad rc car batts? will they overcharge?

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ANYHONDA
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old nicad rc car batts? will they overcharge?

Post by ANYHONDA »

i have a ton of 6 cell battery packs for rc cars 7.2v and was wondering if i could make a 10 cell 12.0v pack and use it instead of the stock battery. would they overcharge? what is the amperage output from the "alternator" or whatever its called. or am i crazy to even think it would work? i have packs from 1500 mAh to 5000 mAh. the chargers they have for them are peak chargers "most now a days" and stop when the batt is fully charged. but they have all kinds of amp settings up to 5 amps and selectable voltages. about 15-20 min for lower mAh and about 45min for higher mAh 4000-5000.
for a reference i have a trickle charger that puts out 120 mAh @9v to charge a 7.2v 1500 mAh pack in 14-16 hours. if i hooked it to a 5000 mAh pack it take days? right?
I KNOW THERE ARE SOME RC GUYS OUT THERE.. what do you think? I'm crazy right??
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Re: old nicad rc car batts? will they overcharge?

Post by cruzingratiot »

your shop manual will tell you the amp out put for your machine

I have looked up the elite sa50 1989-2001 4.0 amps max output
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Re: old nicad rc car batts? will they overcharge?

Post by mousewheels »

There is a cross-up on charging technologies between Lead Acid and NiCad/NiMh.

Lead acid batteries are charged by constant voltage. Lead acid chargers have no means to know when a NiCad or NiMH is charged. NiCad and NiMH are charged by constant current at a low rate And/OR charge complete is signaled by a drop in voltage.

When NiCad's and NiMh's are fully charged, their temperature increases and terminal voltage starts dropping. Both are signals for negative voltage chargers to stop.

For our scooters (Lead Acid chargers), the charger will by nature increase current output as battery voltage drops. This can lead to an overcharge/over temperature issue, and the cell's overpressure vent may open.

I've run 10 cell NiCad and NiMH packs for starting only, but disconnect them once running. I have 'forgotten' , and the pack got quite hot at it went well into overcharge. Mind your pack if it's worth anything to you.

One way to utilize a NiCad or NiMh battery would be to put a series diode inline to block charger output from flowing *into* the battery. You'd need to periodically charge the battery, but it would eliminate the charger technology mis-match.
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Re: old nicad rc car batts? will they overcharge?

Post by kingearwig »

so if one could find a charger like this http://www.ebay.com/itm/IMAX-B6-RC-Lipr ... 4897.l4275 that used somewhere around 2 amps(less?) then this could totally be done...
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