My laptop, Compaq Presario 1510T (also known as Evo N1000c) works fine
off the AC adpter but does not charge my batteries. The batteries are
OK, they charge just fine in someone else's laptop, but in mine the
charging light blinks on and off and nothing happens.

I spoke to a number of laptop technicians who said that since in
laptops everything is part of the motherboard, the only reasonable
solution would be to charge the batteries outside the laptop. The
question is how.
The one external Compaq brand charger I found is around $600.00 and
up, which obviously, doesn't make any sense to buy.

Any ideas?
My batteries are 289053-001 and 240258-001.