[TR] Battery trickle charger

[Randall]

> I have one from Harbor Freight, about 7 years old now, never 
> a problem.
> Probably paid $10 for it.

And they're frequently on sale for even less.  But don't hook them up to a
battery that is deeply discharged or has a shorted cell.  I burned up 3 of
them that way.  The only current limit seems to be the winding resistance in
the transformer.  When I tried replacing it with a stouter transformer, the
plastic box with the regulator melted before the regulator burned up.

This one is more money, but should be more rugged and probably even better
for your battery:
http://goo.gl/hNXpI

-- Randall