Solar car battery charger used on ni-mh

Discussion in 'General Electronics Chat' started by pdc, Jan 1, 2010.

  1. pdc

    Thread Starter Member

    Mar 1, 2009
    10
    0
    Hi,
    I bought a couple of 12v solar auto battery chargers ( think the brand is sunsource) and am hooking them up to 10 ni-mh or ni-cd batteries (serially connected) and they seem to charge up okay and not get hot while doing so. The literature claims there is overcharge protection, but I am assuming it is geared towards lead-acid batteries. I have used one of them to demonstrate solar power to my sons scout group and want to make sure I am showing something safe. What is the diff between a charger for a lead-acid battery and for the ni-mh/ni-cd types?

    Thanks,

    Paul
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Hi Paul,
    You really should not use a charger designed for lead-acid batteries to charge NiMH or NiCD batteries. The chemistries are completely different, and you may well wind up having a fire or burst batteries.

    You need to consult the battery manufacturer's datasheet for their recommendations on charging.
     
  3. pdc

    Thread Starter Member

    Mar 1, 2009
    10
    0
    Thanks. That is what I was worried about. The charger outputs 1.8 watts in optimal sun conditions and the included docs are not very informative. To add worry to woe, I buy outdoor solar lamps on sale to harvest the batteries and cells, so the batteries don't really have readily available data sheets. I get the cells cheaper than online sources and the batteries are like a freebie. Any way to model charging behavior without docs? The last time I charged them was in the fall, so not a full watt situation. They did not even get warm, but I think I am relying on luck and would rather rely on the math.

    Thanks,

    Paul
     
  4. VoodooMojo

    Active Member

    Nov 28, 2009
    503
    53
    a lot of info is available, most of it from sites that are selling their goods, slanted for sure. trial and error can be costly, and dangerous.
    although most of what we really learn is by trial and error!
    we try not to be 'know it alls' so we like to pass along good info.


    http://www.batterystuff.com/tutorial_solar.html
     
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