electric screwdriver help

[stuntpenguin007]

I just picked up an electric screwdriver (out of box) on clearance for $5 at Sears. It didn't have a charger, but I thought I had one that might work. The electric screwdriver says 4.8 Volt on the side of it. I tried a 5v 1A charger, but that didn't seem to work, so I cracked open the screwdriver / drill and found out it has 4 1400mAh batteries in series. I'm guessing each battery is 3.7V. So the battery pack is outputting 14.8V. Should I try a 12V charger? Does the amperage of the charger matter?

After some testing I found out that my charger actually outputs 5.5V, but with some multimeter testing, it doesn't provide power to the batteries. Maybe my charger doesn't fit after all .

Thanks!

edit: I got the charger to supply 5V to the electric screwdriver. Only problem is that it's -5V. The motor won't run, but I'll just rewire the power input thing backwards and see what happens.

[vskid]

The batteries are probably NiCd (or NiMH if you're lucky). They are 1.2v each (4.8v/4....).
Try hooking 5v directly to the motor. I would also check the voltage of the batteries, they could be completely dead.

[stuntpenguin007]

Thanks, I got it working. I just had to rewire it internally, so instead of getting -5V, now it gets +5V.