-=> JOE PAULSON wrote to ALL <=-


 JP>  I have a Skil Portable drill with two battery paks,
 JP> (Skil No.92927 12 volt Super Power Pak).
 JP> One works fine but the other puts out only 8.5 Volts
 JP> after charging.
 JP>   I've discharged it several times down to about 3 volts
 JP> and recharged it with no effect.One or more of the "C"
 JP> batteries was defective.
 JP>   After about 6 months,I decided to see what was in it.I
 JP> took it down to my table saw and carefully cut off one side
 JP> about 1/16" at a time until I had an opening.Then I used a
 JP> screwdriver to open it all the way up.The cover came apart very
 JP> easily and exposed the whole assembly.
 JP>   Inside I see 10 cardboard covered " C " batteries,two sets
 JP> of two and one set of 6. A voltmeter check shows no voltage in
 JP> any.Must have all discharged over 6 months.I'll try to find the
 JP> defective batteries and cut the welded flat strips to give me sets
 JP> of 2 batteries for flashlights.
 
 Or you could zap them with a short high current pulse and clear the 
 dendrites that form inside the bad cells shorting them out.
 Last setr of nicads I bought lasted 9 years and than I lost them, 
 they were still good.
 A simple zapper can be made with a 50 - 80,000 Uf capacitor rated for 
 about about 50 volts and charged with a DC rectified transformer
 rated at 35 volts or so, it'll float higher on such a light load
 as you'll present.
 Chose a resistor to place inline before the cap to limit 
 charging current to 1/10th of individual cell
 capacity and put a heavy open style knife switch single pole
 single throw between the cap and the battery pack.
 Leave the cap to charge with the switch open and the pack connected 
 for a minute and than close it zapping out the short.
 Several zaps may be required and as an added bonus it's a
 simple charger as well though you must remember to
 disconect it after the appropriate interval, 10 x C rate.

 

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