A "trickle charger" and a "float maintainer (charger)" are two different items.
The trickle charger will keep charging even once the battery reaches full charge
and will fry a battery. I found this out the hard way, when I forgot to unplug it once
and left it on for a week.
A maintainer will bring a battery to full charge and shut down, but will also restart,
for lack of a better wording, when it senses the voltage has drained below a certain
level. They are not for charging of a dead battery, but maintaining the charge of a good battery.
I don't know if the one from HF works as well as the more expensive ones, but it does
work.
(haven't been to the site for a while and thought I'd add my 2 penneys worth).
