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12 volt cordless drill

Discussion in 'Home Power and Microgeneration' started by John, Oct 27, 2003.

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  1. John

    John Guest

    I was given a 12 v cordless drill with 3 spare batterys.Any reason why I
    cant use a trickel car batt charger to recharge the batterys??I did not
    get a charger with the drill $60 for a replacement.
  2. mark Ransley

    mark Ransley Guest

    you wont get them fully charge, nicads require apx 15% more than 1.2.
    per cell Also a car battery wont trickle charge them it will blast them
    Nicads are ovecharged charged when they get warm, watch out. Or peak
    charge vith a volt meter , when volts drop stop.
  3. Steve Stone

    Steve Stone Guest

    Car batteries accept a charge at a different rate of amps and volts over
    time than NiCad's or NiMh or Li-Ion. You might get away with it for awhile
    but will probably shorten battery life. Or if charged too quickly they might
    blow up only you.
  4. FWIW,

    I have a 12 volt cordless drill, which came with two batteries and a
    1-hour charger. The charger got smoked in a power surge. I have tried
    connecting the batteries to a 12 volt car battery charger, and they
    will NOT accept a charge. I can put some current into them, but they
    don't charge up. I used a small lamp bulb in series to limit current,
    and I have my charger plugged into a Variac so I can control the
    voltage. Even with 130 VAC going into the charger, the darn things
    won't accept a charge.

    Needless to say, the replacement charger from Ryobi costs 2/3 of what
    a new drill does. Oh well, that's why I bought a 12 volt cordless;
    figured if the batteries died I could put clip leads on it and run it
    off a car battery.

    BTW, these battery packs have 3 terminals on them; anyone know why?

    Gordon Richmond
  5. A car battery charger (as others have told you) won't work very well
    in this application for a number of reasons. Also, the charger is
    probably very specific to the batteries, any other charger may not do
    a proper job of charging them.
    There's a thermistor in contact with the cells to detect the end of
    charge by measuring a temperature rise.
  6. That's not the only concern, many car battery chargers are just a
    transformer and a diode, producing large peak currents and small
    average currents. I don't know if that's a good idea for a NiCad...
  7. Vaughn

    Vaughn Guest

    A one amp or smaller trickle charger will probably do just fine, but you
    will have to take care to not overcharge your batteries. The simple and
    dirty way to charge NiCad's (still used in many cheap units) is to use a
    higher voltage source (18 to 30 volts for a 12 volt battery) and a current
    limiting device such as a 24 volt 100 ma. light bulb. This gives something
    approximating a constant current charge, with a low enough current to keep
    from immediately ruining the battery if you leave it on charge too long.
    Leave the battery on the charger just long enough to get a full charge,
    perhaps overnight.

  8. mark Ransley

    mark Ransley Guest

    I will tell ya Vaughn and STormin Moron you both know less
    about mechanics than is in my toilet, SHIT....So where do we start
    the inteligence marathon. it has to be a game worth 1,000,000 us
    or BLOW , money talkes , BS walkes
  9. Yes, you certainly will. Don't hold back, Mark, tell us how you
    really feel. And then consider contributing something positive,
    constructive, and thoughtful to the discussion. Any discussion. Or
    get plonked, either way, it's up to you.
  10. mark Ransley

    mark Ransley Guest

    William pn Smith, How do you do it . Charge a 12v nicad off
    a 12 v lead . See whos Right, smart ass.......or shut up
  11. <Plonk>
  12. Vaughn Simon

    Vaughn Simon Guest

    Say goodbye mark.


  13. Bob Adkins

    Bob Adkins Guest

    See an inexpensive, very versatile NiCd charger here:

    NiCD's chargers go by cell count. You must figure the cells in your battery.
    It's probably a 10 cell, so get one rated for 10 cells, which the above one
    is. Most NiCD batteries require a 15 hour charge to store full power.

    You may have to adapt a jack or connector, or just use small alligator

  14. Find out what the total Cells Maximum current capability
    is (by opening the case and seeing what sort they are...);
    Search on the Web for Battery info` relating to the Cells;
    Use maybe one or two current limiting resistors in
    series while charging, these will be of the ceramic,
    possibly 40W rating at maybe 10 or 20 ohms?
    Use a test meter in series to measure the current so that
    you can calculate what the total charge time will be.
    I`ve been doing this with various Batteries for years.
  15. larry

    larry Guest

    I don't have the original question in my list ....
    Why 3 spare batteries?
    Did you buy it that way or was it given to you, second hand. Why the
    question because usually you get one spare battery.
    Please don't charge the battey using your car battery. The cordless drill
    should have come with it's own charger.
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