On Sat, 26 Aug 2006 12:49:26 +0100, in uk.d-i-y Pete C
wrote:

Does the drill have a standard DC socket? If so why not make a lead.

Just use a cigar lighter plug, DC power plug lead and a power resistor
to drop the voltage and regulate the current.

These drill usually have 1Ah batts, so a lead with a 3 ohm resistor
will drop ~9v at 300mA, for a charge time of 3-4 hours.

You mean 30 ohm!!! 3 ohm will blow up either itself or the driver or
both.

Apart from that, there is no means to terminate the charge when the
driver is charged up. This scheme will keep pushing 300 ma into the
driver as long as connected, which won't do it any good.

It's easy enough to design a simple charger using an IC and very few
additional components, and I daresay a search for "battery charger
circuit" will turn up loads. Here's one

http://www.angelfire.com/electronic/hayles/charge1.html

Phil