I am no electrical guru, but I have been using a similar system for
over 10 years and never had a problem if I inadvertently had more than
one charging source going at the same time. All of the sources other
than the alternator are fully automatic and therefore can adjust to
that situation.  My solar panel is always on when under way and neither
the alt. or the controller minded. The only thing that I found to be an
issue was when the shore power is hooked up and I want to use my 30 amp
charger, I need to remember to unplug my hardwired trickle charger so
that the big charger is not tricked by that input voltage. Same goes
for the solar charger, so I unplug that, too. That way the 30amp
charger can do a proper test mode and charge accordingly.

Unlike my current 90 Syncro Westy which has a gowesty aux batt kit, my
84 Westy had a marine battery switch so that it was easy to
isolate/combine/disconnect either battery. That system was great for
working on the electrical system too. With a switch like that I could
instantly go from one to the other in case of a dead battery. Downside
was that it was manual and you had to pay attention to which battery
was charging and which battery you are using as the aux. while camping.

Thanks for all the good info on your system, Loren. Very helpful and
appreciated!

Keith O

On Jul 18, 2007, at 10:35 AM, Automatic digest processor wrote:

> Date:    Wed, 18 Jul 2007 09:51:51 -0700
> From:    Loren Busch <starwagen@GMAIL.COM>
> Subject: Aux Battery Charging Alternatives Question for the Electrical
> Gurus
>
> Right now I have wiring in place for three ways to charge my aux
> battery.
> First, and permanently connected, is the alternator when engine is
> running.
> The next two are wired right now so that only one can be connected at a
> time: Solar charge controller (and solar panel) and an onboard 30 amp
> 'smart' charger.
> Question:  What kind of problems, if any, would I encounter if all
> three
> were connected to the battery at the same time?  Assuming that only one
> would ever be running at any time, would I expect problems such as the
> solar
> controller seeing the voltage from the 110v ac charger and causing
> damage?
> Or the solar controller seeing the voltage from the alternator and
> having
> problems?  Or any other combination that should be avoided?  Just to be
> careful I'm now set up so that the solar and the 110v ac charger can't
> be
> connected to the battery at the same time but the ideal system would
> be to
> have them permanently wired in.