John - If it went completely dead, I suspect the battery is done.
There are some cures that someone here may suggest like shocking the
battery with with a higher voltage, but don't expect miracles. If your
battery is newer, there are probably screws to take it apart. Measure
the voltage at individual cells and I expect you will find at least one
dead. Some specialty electronics stores will sell replacement cells,
but I suspect if you have one bad, the others are close. It may be
better to just buy a replacement. A quick check at Amazon for "dewalt
12v battery" shows some for about $30.
Don't know why they are so expensive. When the batteries from my first
Dewalt 12V drill became worthless, it was actually cheaper to by a new
drill with two batteries at Costco than get the batteries individually.
As to measuring the voltage at the charger terminals, don't expect
accurate readings without a load. You could take a couple fine wires as
someone else suggested, but be careful you don't short anything or you
will be in the marked for a charger as well.
On 12/22/2010 7:25 AM, john niolon wrote:
> I'm having trouble charging Dewalt batteries... some it may be old batteries
> but I'm wondering if my one hour charger is dying... Dewalt 9107 one hour
> charger when I put a meter across the contacts down in the charger I read NO
> d.c. voltage. although the battery is getting warm and slowly taking a
> charge... I had a completely dead 12v battery and started charging it with a
> hotter power supply 26volt for a few minutes... it came up to about 8 volts
> and I then stuck it in the 9107.... 4 hours later it's up to about 10 volts
> ??? This is a 2.8 amp charger and should do better than this... discounting
> a bad battery pack... how can I test the charger ???
> Nothing says "Poor Workmanship" like wrinkles in your duct tape!!
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