I've been trying to get some specs on this unit - seems like a really
good way to charge trolling motor batteries on long runs spot-to-spot
on a large lake or on runs from spot-to-spot inshore.

http://tinyurl.com/564jl4

I can't seem to find anything that gives the specifics on how this
works. I'm speculating here, but I would assume that it works to
charge the trolling motor batteries once the main battery system is
charged. I'm guessing that is must work on an interrupted basis -
meaning that once the starter battery is charged, it switches to
charging the 24 volt system.

Here's the thing - how?

If I were designing this, I would make it so the engine would have to
be running above idle and the charger producing more than the nominal
13.6 volts needed to run the engine. That would mean that each battery
in the 24 volt system would need to be charged a little at a time -
like say a minute for one, a minute for two - back and forth until the
batteries were charged.

That's the way I would do it, but there are other ways. I just can't
find out how it works.

Anybody have experience with these things?