Date: Wed, 17 Apr 2013 01:21:18 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Solar controller question..semi off topic.
In-Reply-To: <CAHTkEuJq0MH3tr6owXpKcjGOmV-7guX9yFyyKDHrJsXWOaMGrQ@mail.gmail.com>
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Solar power gets a little tricky. There is the maximum voltage output,
unloaded or "open circuit" and then as load is applied, (current drawn) the
voltage will drop. That is why there is a rating of X volts at X amps.
Now the idea of the charge controller is to take that power and regulate it.
You need to control the voltage under varying panel outputs and current
loads. There are fixed controllers and then there are controllers designed
to actually charge batteries.
You can't just go ahead and willy nilly put panels and charge controllers in
series or even in combination. Ideally you want one controller sized to
handle the maximum capacity of as many panels that you plan to get. Panels
added in parallel should have match voltage outputs.
The 2nd controller should be able to manage both of those panels wired in
parallel to the inlet. The more expensive units likely offer some additional
functionality that justify the increased cost.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Don Hanson
Sent: Tuesday, April 16, 2013 7:23 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Solar controller question..semi off topic.
Respond off list, if you think it would be of no interest to the general
list population...
I recently got a second solar panel, a 75w 4.5A 16.6v rated with 21.4v
max... I was running this during the winter with our old 40w plastic
panel,which had a built in charger/controller. I do not have any specs on
that, and that is out of reach right now....The two panels kept our two
large deep cycle/marine batteries well charged...the original 40w panel
alone was not up to the task, except with very sparing electric usage and
bright full sunshine every day...
So, I brought the one newer panel home with us and I would like to get a
proper controller so I can use it to charge the vanagon or any other
'remote' battery I have need of during this summer..
But I have no idea what any of the numbers mean on the charge controllers
I am looking at, when it comes to selecting the proper one...Here's the
numbers I am thinking of from the Northern Tool company...
3.5 amp- 52.5 watts....$20
8.5 amp- 127.5 watts. $29
10amp. 150 watts $59
30amp 450 watts $99
I am guessing the second one would work. Cost is a factor for me, too.
I will be using this on various starting batteries, mostly. If need be, I
will take the controller out of the circuit again when I go back to the
desert and hook it up in series with the second panel and the controller
that worked fine for us this spring and winter....
In order to charge a big fat RV deep cycle battery, do I need a big
expensive charger/controller? What do these numbers all mean? Anyone
want to give me a quick bit of advice on this?
I just stuck the panel in the sun and I get 21.x volts out of the
wires....a plug on a 8 gauge extension cord a few feet long. I am
planning on keeping a plug, after the controller, and ending it in a couple
of jumper clamps for use around the ranch and campsites...
Thanks...Don Hanson
