On Tue, 25 Nov 2008 10:58:19 -0500, "Eisboch" wrote:

I re-read the specs on the Guest unit Tom is referring to. It specifically
says, 2 outputs of 12volts DC, 10 amps each. But then it says for "24"
volt systems. That is confusing.

Yes.

There are two possibilities that I can think of. The first assumes a
12 volt starting battery *and* a 12 volt trolling battery. In that
case it would merely function as a combiner once the starting battery
is fully charged. Combiners have been around for a while and are
just an automated switch with voltage sensing.

The second possibility assumes a 12 volt starting battery but a 24
volt trolling batt. In that case it would have to contain a DC to DC
converter which would activate once the starting batt was at full
voltage. If you already own a 24 volt charger this function could be
implemented by driving it with a 12 volt inverter.

I'd call Guest and get a clarification. On the other hand my
impression of most Guest products is not all that favorable.