For my motorhome batteries I use a
product called Battery Tender. I have
one for the vehicle battery and one for
the house battery. These units, and
I'm sure there are other brands, are
designed for long term use. They are
made to prevent boiling and other
battery damage. Google battery tender.

Herb and Eneva wrote:
It`s winter time and cold and as usual the tractor battery is almost
dead. The regular charger and the trickle charger boils
out the water. A neighbor says he uses a " float charger". Can someone
tell me what a float charger is amd what does it do?
Thanks a lot