Date:         Sat, 4 Jul 2015 17:05:01 -0700
Reply-To:     Neil N <musomuso@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Neil N <musomuso@GMAIL.COM>
Subject:      Re: Batteries and solar panels!
Comments: To: pbrattan@gmail.com
In-Reply-To:  <CAOBs5F4=G+6M55mC6aiK7cZsdVt7FXAmQDoFaUZHysrP=ZjoPQ@mail.gmail.com>
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you're welcome Patty. I'd be curious how having two or more
batteries wired together full time affects how one or both receives a charge.
i.e. with one at 80%, the other at  30%, I'd assume the charge time
would be greatly
increased, depending on the output of the charger. But.....
IF one were dead, unchargable, or near so, would that battery be such
a huge load
that it impedes flow of charger to the good battery?
I can't say for sure. Details on that are beyond my knowledge base.

Bottom line: disconnect each battery, inspect, measure, charge each as
needed for now.

If your Dometic fridge is wired OEM, it should not operate off the
battery no matter what.
On the other hand, it could've been modified to run off a charge
converter and-or wired to
run off a given battery, engine off.

Battery sizing has been discussed at length here but as one example....

My TF49 12V truckfridge, will easily last overnight on a ~ 100 Amp hour battery.
But if it's cloudy, or no sun (I have a solar panel), I **might** get
2 days out of that battery. More like 36 hours at best in high ambient
temps.

For me, I'd use a battery switch to connect or disconnect the
batteries from each other. Connect them for charging while driving,
(fridge running too)
disconnect them while in camp so I don't draw down the starter battery.
I'm not sure if there's a switch that would do this AND disconnect all batteries
from the vehicle wiring (in event of major short)

Neil.


On 7/4/15, PB <pbrattan@gmail.com> wrote:

> Yes, stock.  Thanks for that explanation, Neil.  I didn't realize a bad aux
> battery would affect the engine battery.  It's been plugged into electrical
> for the past 3 (hot) days so I could see fridge temps throughout the day,
> although, AGAIN, I don't know if I hit the wrong switch on the fridge panel
> and chose 12 volt instead of 120.  (I'm going to put stickers in English on
> the fridge panel to avoid a repeat!)
>
> A 12 volt fridge is on my wish list, to be powered by solar panels.  Also,
> would like all house lights to be powered by aux battery.  That's why I'm
> asking about batteries now.  Don't want to learn later down the line that I
> should have gotten a different battery.
>
> Aux battery switch sounds like a great idea.  So if it had an aux battery
> switch, I would have switched off the aux battery and just used electrical
> power from the cable?  (I'm somewhat a dork regarding electrical info, but
> I think I understood this idea!)
> Patti
>
>

--
Neil n

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