Rechargeable batteries and chargers

Discussion in 'Engineers' Talk' started by PowerTool, May 8, 2005.

  1. PowerTool

    PowerTool New Member

    Just a question out of curiosity -

    As you can get,for example,cordless tools with 1 hour chargers or 3-5 hour chargers - is there a difference in the batteries themselves,or just the rate the chargers work ?
    i.e. could an 18v 1.3Ah battery that came with a 5 hour charger be recharged on a 1 hr charger or vice versa ?

    (No,I haven't tried it,and wasn't planning to either ;) )
     
  2. harry

    harry Member

    I had a power devil 18v drill and cordless circ.saw.The drill was 3-5 hr charge,the saw 1hr.The batteries are identical except the 1hr one had three connections and the 3-5hr had two. You could swap them in the machines but not in the chargers.hope this makes sense.Harry
     
  3. markysparky

    markysparky New Member

  4. johnhififan

    johnhififan New Member

    Some tools will use sealed lead acid batteries (small versions of a car battery) these can accept fairly high charge rates. Others will use nickel cadmium which generally take longer. But use the charger intended, trying to charge faster beyond the rate of the battery is very dangerous (leaks explosion fire).
     
  5. wardoss

    wardoss New Member

    The difference in charge time relates to the amount of current it is putting into the battery. The quicker charge puts more energy into the battery hence a quicker charge.

    However with NiCad the quicker you charge them the more power they will give but the overall life span will be reduced. For the purposes of power tools the longer charge would be better if you could get away with it. The 1hr chargers are so designed that you can you one battery while the other is charging and it should be charged before the other battery is flat.
     
  6. JoeB

    JoeB New Member

    The third terminal is a temperature sensor output, when rapid charging a battery, espically NiMH they get hot and can explode. The third terminal tells the charger to stop charging if the peak is missed (the batt terminals hit a peak voltage when fully charged, the charger normally looks for this peak and stops, but sometimes it can be missed).


    Joe
     

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