I am thinking of installing two battery maintainers in my boat, one for each battery. It is cheaper to buy two single units than one that will handle more than one battery. I have also found a 12 VOLT SOLAR PANEL BATTERY CHARGER 1.5 Watts on Ebay for $14.00 each [it's the red one]. Has any one had any experience with either system? :?
Only that they don't work well on cloudy days. Now you have all the wisdom I have on solar power. :roll: Bud
Those type of low wattage units will maintain a battery charge, but will take forever to charge a well drained battery. They are intended to keep a battery "topped up" and aren't really suited to use as a charger. If your battery usage is low and you don't drain you batteries very hard (like several hours of trolling motor use will) they will keep them "fresh". They're great for keeping batteries in good health while she sits waiting for her owner to take her out for a splash again. I use similar types for just that, which beats lugging the big charger (and a long cord) around the yard to keep batteries at full charge.
To be honest, 14 bucks sounds like what they cost brand new (the low watt ones).
I've installed these solargizers on our boats(different supplier same part no.):
http://www.batterystuff.com/battery-rest...IS12L.html
They're about the size of a 1/4 sheet of sandpaper and maybe 1/2 thick. One per battery. IIRC we put 3 110Ah AGMs in those boats with one panel per battery. As Paul said - they are just battery maintainers, not chargers. These particular ones have a pulsed output that's supposed to reduce sulfation on the plates over the life of the battery. Don't have any longterm info on how well that works. Also, each one ships with a charge controller that includes the internal diode.
A little more than $14, but really well built. If the boat is stored in the fall with charged batteries, they'll extend the batteries' self-discharge curve through the winter.
I decided on the 120 V. 3 A. plug in with a maintenance monitor built in.