[DuoList] PB 2400 battery refurbish???

Frank casey8 at mchsi.com
Mon Oct 11 08:44:44 PDT 2004


More info on fixing battery packs. This is for cordless drills, but 
applies to any battery pack:

There is nothing more agravating than having a battery pack die on 
you in the middle of a job. A new battery usually cost $50 or more, 
and a rebuilt one usually cost about half that. You can repair it 
yourself for a few dollars.

You will need a soldering iron, solder, and a voltage meter.

Each battery pack contains a series of sub-c batteries that store 
(1.2) volts each. For example, an 18 volt battery pack contains 15 
batteries, a (14.4) volt pack contains 12 batteries, and so on. A 
sub-c battery costs under $5 and usually it's only 1 battery that 
cause a battery pack to go bad.

First you will need to number your batteries. Follow the positive 
charging contact on your battery pack to the positive terminal of the 
number 1 battery and mark it. Follow the negative terminal to the 
number 2 battery and mark it. Repeat this process until all of your 
batteries have been numbered.

Now to find the bad battery. Place the positive lead of your meter on 
the positive terminal of the number 1 battery. Leave in place. Place 
the negative lead of your meter to the negative terminal of the 
number 1 battery. It should read (1.2) volts. If so, check the 
negative terminal of the number 2 battery. It should read (2.4) 
volts. For each battery you check, the voltage should increase by 
(1.2) volts. Eventually you will come across a battery that will not 
generate any charge and the voltage will not change. This is your bad 
battery. Replace with a similar type (NiCd or NiMh) sub-c battery 
with solder tabs (available at Radio Shack).

Now your battery pack may be undercharged and the sub-c batteries may 
register less than (1.2) volts. Simply double the registered voltage 
for each battery you check. Since the batteries collectively balance 
a charge, each battery should be very close in voltage to the others.

Hope this is of use to someone. I hate to see people throw away 
perfectly salvageable battery packs.

casey


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