Re: [A/S] Univolt and Solar Power

[Don Horn <donhorn@xxxxxxxxxxxxxx>]

Roger,

If I understand correctly, you're putting 120v AC from the inverter into the
Univolt?  If so, why?   Sounds like you've got some kind of infinite loop
going on there.   (Are you really converting 12v DC to 120v AC, putting that
into the Univolt, which converts it back to 12v DC again?)

Why not connect the inverter output downstream from the Univolt on the AC
side?  The battery should supply 12v to all the DC equipment without the aid
of the Univolt--the Univolt just adds power to those same circuits when
you're plugged in to AC, and charges the batteries at the same time.  It
will also overcharge your batteries if kept on long enough, since it puts
out a constant voltage in the neighborhood of 13.5-14.4 volts.  As Jim
mentioned, it will boil them dry.

Better yet, go ahead and chuck the Univolt as you suggest, and keep the
systems separate.  If your inverter is a combination inverter/charger, you
have no need for the Univolt, and I'm surprised you haven't already removed
it.  If you have an inverter only, replace the Univolt with a decent charger
of the type previously recommended on this list, and connect the shore power
line directly to your AC breaker box.   I wired a short air conditioner
extension cord to my charger so I can plug it into a 120v outlet, but you
can also hard wire it to the 120v and put a switch on it.   I don't think
that the charge line from the tow vehicle goes through the Univolt at all,
and shouldn't be affected.  It may connect at the 12v side of the Univolt,
and you'd need to ensure that it remains connected to the battery when you
rewire the system. 

By the way, you can have any number of charge sources connected in parallel
to your battery at the same time, as long as they are properly regulated.  A
good AC powered battery charger will sense when you're getting enough
current from the solar panels, and cut back its output, as will the solar
panel controller.  I think the voltage regulator on your tow vehicle is also
adequate, if not as good as the other two.   If you have enough solar
panels, it might even be a good idea to disconnect the tow vehicle charge
line, but I'm not too sure about that.

Don