"y_p_w" <y_p_w@hotmail.com> wrote in message news:33f33c40-0b42-4ed5-a909-

I've heard other
> comments that it's effectively a trickle charge that could safely be
> left on a fully charged car battery for days if not indefinitely.
IIRC, batteries were damaged in the old days right in the showroom because
of trickle chargers in the range of 1 -1.5 amps.

They might be left on charge for months ( thus making the dry charge battery
a step forward).

You have at least two or three options:
(1) Make sure all the lights and systems are off ( which sounds like it does
not work for you
and your present situation)
(2) Buy a unit which will sense your battery condition, and disconnect it
from the car's electrical
system if the battery is discharged to a low level. (Google for them. They
exist)
(3) Use the trickle charger as a matter of course. I dont like to leave a
battery a long time with
1 amp or more of charge, so I sometimes put a 12 v lamp in series with the
leads and decrease
the charge rate to a (bias level) 100-250 ma. Dead simple, and works fine.
Wattage of the
lamp determines the resistance, so you can select values to limit your
charge.