Date: Mon, 22 Aug 2011 18:02:18 -0400
Reply-To: Kim Brennan <kimbrennan@MAC.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Kim Brennan <kimbrennan@MAC.COM>
Subject: Re: auxiliary battery wire gauge
In-Reply-To: <FF4E2F66DE0A4EB9A7B93D4E1DA075C1@troyb5bff49d63>
Content-type: text/plain; CHARSET=US-ASCII
There are two reasons for using larger wiring, run distance, and current draw. Essentially if you need to do a longer run to connect the batteries up to their charging source (or consumer), you want to use a larger gauge wiring than you might ordinarily need if the source/consumer was right next to the battery. I don't have a chart handy, but you might want to use a larger wire to the batteries under the seat, but the smaller gauge between the batteries that are grouped together.
On Aug 22, 2011, at 3:31 PM, Troy wrote:
> I just ordered another 5 deep cycle wheelchair batteries (Universal 12220) so that I can get rid of my standard lead acid battery I've been using for the past 3 years, which will bring me up to a total of 7 of this little critters, and should provide lots of reserve power (154 AH) for my DC fridge, furnace, etc. 3 will live behind the driver seat, and then an extra 4 under the rear seat.
>
> I know a lot of list members are using the 1315 Surepower relays, but before I ever knew about them I ordered one of the solenoid kits from Go Westy. I do not plan on using these auxiliary batteries to start the vehicle. If the main ever starts to go, I currently have a switch so that I can connect the main and auxiliary batteries together to trickle some battery back to the main, but again I do not start the van this way, and would break the link before starting.
>
> With that said, is there any reason to use super heavy duty 4 or 6 gauge wire to connect the main and auxiliary? Currently I use an 8 gauge wire (much easier to work with), and have not had any issues that I am aware of. 8 gauge can handle nearly 50amps, so is there any problem here? In a pinch, I probably could start the car if I didn't go more than a few seconds. There is a 50 amp breaker installed anyway.
>
> As to charging the auxiliary batteries from the alternator, what's the maximum amount of current that I would see? I typically charge batteries at no more than 4 amps, using my 3 stage charger. What kind of amps does the alternator put out? I'm just trying to determine why the super heavy gauge wire is needed if you're not using the auxiliary batteries for starting the van.
>
> As to the 2nd set of batteries under the seat, I would think I would be better to use a separate 1315 relay there hooked directly to the alternator, although I guess I could route a wire up to the front. This is the way I currently have things set up, and I believe there is a 10 gauge wire between the two. I will change out this cable, but this one is protected by a 30 amp fuse, so have not been losing sleep over my setup in general.
>
> So, could somebody please advise if this setup is okay or if I need to change things. With new batteries on the way, I want to make sure this is done correctly.
>
> Troy
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