"Fritz" wrote in message
oups.com...
My charger for my cordless drill recently stopped working. My drill is
dead as a doornail, and I've got projects pending. It's an off-brand
(Master Mechanic), and I've had some difficulty locating the
manufacturer. Efforts to purchase a new charger have gone nowhere.

So...I was able to determine that the fault lies with the AC/DC
converter ("wall-wart"). It's rated at 200mA and 14.5VDC, but at the
moment it's putting out essentially 0VDC (verified with my
multitester). I went to Radio Shack and purchased a 15VDC 1A wall wart,
with the intent of cutting and splicing it to the charger, but when I
tested it's output myself, it's actually kicking out 20.33VDC. This
seems high.

What happens if I solder a 20.33VDC output to a charger that's used to
operating with 14.5VDC? Will it damage the battery? Cause an explosion?
Other deleterious effects?

Radio Shack also had a (rated) 12VDC wall-wart. If it runs hot like the
15VDC version does, I might actually get pretty close to 14.5VDC. Would
that be a better idea? Do the outputs from these low-grade AC/DC
converters always vary that much from their rated output? And does
anyone sell converters that will match the OEM one fairly closely?

The wall warts are not usually regulated. They will drop under load. Look
for one that has a current rating (mA) of the battery you are charging. The
voltage can be rated a volt or two more. The higher current rated chargers
will not drop the voltage to as low a level as the lower current rated ones.
This will tend to charge the battery faster. For short times this is not
too bad, just don't leave the charger on the battery all the time.