In article .com,
ed wrote:
So here's the question: what about this battery pack makes the
transformer heat up to the point it burns out? There doesn't seem to
be a short in the battery pack, just a few bad cells. . .I don't
understand why this gives the transformer such grief.

Ni-Cads should really be charged constant current with a 'simple' charger.
Now if the charger itself was designed as a constant current device, then
increasing the load (with say a short cell) shouldn't worry it too much.

But I've seen so called rapid chargers on cheap power tools (4 hr charge)
where the charger is simply unregulated DC with a series resistor to give
something *vaguely* near constant current.

And of course few carry a stopwatch around to make sure they don't cook
them - as you will, if the four hour limit is exceeded by much.

So I'd have a look inside the charger base to see what it's actually got
in the way of electronics.

--
*A nest isn't empty until all their stuff is out of the attic

Dave Plowman London SW
To e-mail, change noise into sound.