Date:         Wed, 17 Apr 2013 08:47:50 -0700
Reply-To:     Loren Busch <starwagen@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Loren Busch <starwagen@GMAIL.COM>
Subject:      Re: Solar controller question..semi off topic.
Comments: To: Don Hanson <dhanson928@gmail.com>
In-Reply-To:  <CAHTkEuJq0MH3tr6owXpKcjGOmV-7guX9yFyyKDHrJsXWOaMGrQ@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

​RE: Solar Panels and Controllers
Don, the subject has been coverd by the reponders up till now.  But let me
add this.
You mentioned connecting the two mismatched panels you have in series.
They MUST be connected in PARALLEL!
As for controllers I have and have used two different controllers, one
conventional and one MPPT (cheap, out of China off eBay).  Both work fine
and I've used them both with two 50 watt panels deployed outside the Westy
and now with a single 120 watt panel on the roof.
The difference I've seen is that the conventional controller goes up to
about 14.4 volts in good Sunlight and the MPPT controller stops at 13.3
volts.  14.4 volts is about what the batteries see from the alternator
while the 13.3 volts is the normal 'float' charge on a lead acid battery.
I my case I'm using an AGM battery for the aux and they like to see about
14.4 volts for charging.  So I'm using the conventional charger most of the
time.  Plus it's more reassuring to see the higher voltage on the meter all
day :)
Note that I am probably not pumping as much current into the battery at any
moment with the conventional controller but the battery is topped off
before noon on most days with Sun.​