Date: Thu, 8 Aug 2013 12:17:56 -0700
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Re: Electrical Math Check Please? (Westy Solar Panel)
In-Reply-To: <CAB2Rwfivo0etoAzrh78RtRs5ph5JYR6pfcSzqkmtF+Wr0TtLUQ@mail.gmail.com>
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Wow, you are worried about .03 volts of line loss? Just kidding you....
You can always reseal any box...often better than the original makers have
done. We never used to trust factory-supplied seals at the boatyard where
I worked once...we always took electronic housings apart and did our own
sealing...Of course, the Marine Enviornment is worse than a Vanagon sees,
but still...
I've been running my Dometic on propane again, using it to keep my
lunches and water cold as I have been working in triple digit temps...
Flawless performance from that,...going on three weeks on one 5 gal tank of
propane now...Pretty small capacity, the dometic...but it does work just
fine.
On Thu, Aug 8, 2013 at 11:44 AM, neil n <musomuso@gmail.com> wrote:
> Hey people. My reason for asking is below.
>
> I had assumed the amount would be small (negligible) but want to
> calculate the approximate difference in voltage drop between a "round
> trip" of 20' and 23', 2/10 wire between panel and controller. It seems
> there's more factors involved than I include here, but a double check
> of my rough calculation would be appreciated.
>
> Solar panel max. output: 7.9 Amps @ 18.99 Volts.
>
> For #10 wire, using 1.24 Ohms per 1000' ........
>
> 20' x 1.24/1000 = .0248 Ohms
> 23' x 1.24/1000 = .0285 Ohms
>
> Using rounded off panel values:
>
> .025 Ohms x 8 Amps = 0.20 Volts
> .029 Ohms x 8 Amps = 0.23 Volts
>
> So adding 3' of wire(s) causes a voltage drop of 0.03 Volts?
>
> My panel wires have MC4 connectors crimped on. I've emailed the vendor
> for info, but hesitate to open the junction box on the panel as it may
> be weather sealed. (had thought that end of the wire would be a
> smaller OD)
>
> Instead of drilling large holes for the MC4 connectors to pass through
> the pop top, I'd like to drill one smaller hole and use the supplied
> 2/#10 FLAT cable that c/w the kit. I don't know if there's a grommet
> for that type of cable but am certain I can seal the hole well and
> would do same even if a grommet was used.
>
> Neil.
>
>
> --
> Neil n
>
> Blog: tubaneil.blogspot.ca
>
> '88 Westy http://tinyurl.com/c8rlw6p
>
> '81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/
>
> Vanagon VAG Gas inline-VR Engine Swap Group:
>
> http://tinyurl.com/d7gd5ej
>
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