Split battery bank to multiple locations?

I had a 1964 Airstream with one 12v battery in the rear. Had #10 or #8 wire from the tongue to the battery. At first, just hooked up to small wire at rear of TV. Would run out of juice quickly. I do not think it EVER got fully charged, unless charged at home. Alternator was my only way of charging on road, unless hooked up.

I then put a 2nd 12v on the tongue, and ran a double #4 cable from engine to that battery, and left the smaller wire in the trailer. About 4X the power! I doubled the battery, and, with the big cable to the front of the trailer, I kept the voltage up enough that I actually got them full on the alternator!

That system worked great for the number of years I had the trailer. I think you will be fine. Big copper wire is your friend.

FWIW, for weight distribution and economic reasons, I built an interior battery box for 2-6V's that is located just forward of the front axle. Plywood, plastic sheet, and a vent are cheaper than buying AGM's. I also have two banks--one comprised of 3x AGM telecom batteries, the other, the aforementioned 6V's. The 6V's are 6' from the 12V distribution center and I connected them with 1/0 welding cable.

There was a post here long ago with pictures. Where some guy just ran his other batteries in the back bed in his pick up truck.

Sure, more specifics of what my situation is...

I have a 40A converter/charger, but plan on typically being off-hookups so I'll rely more on 30A/400W solar array to charge as much as possible during midday. I have a 1kW genny to make up any difference (but would it to be the exception rather than the rule).

My expectations are to live within that 10%-50% DOD that a fast charge off the solar can provide (and not worry about the last 10% that a slow perfect charge.

So if I had 4 GC2's, that's roughly 200Ah working power, which is plenty for me if I avoid Florida in the summer.

I definitely don't want to get into the complexity of managing the banks independently at all... as I believe @Mexicowanderer alluded to. If I can't make them work seamlessly as a single bank, then I'll figure something else out (dios mio are AGM batteries expensive).

RoyB wrote:
I am going to attempt a similar installation here soon...

Dang it Roy! Now your making me regret buying an old cheapo trailer. That really does look like a great install. Unfortunately, I have an 02' which has 320lbs of water under the bed (that is, on the tongue). Adding 200# of batteries (2-24's to 4-gc2's) is probably not ideal with my 1/2 ton truck with 500# already in it's bed.

I think the same design flaw undermines many of the other options about putting them on the frame rails. It's kind of too bad... the trailer has 2500# carrying capacity - but god knows where you can put it without killing the tongue. Maybe it's possible though - I will give it some thought.

$adly the tongue weight i$$ue had driven my to option #2 which was AGM batterie$ under the $ofa. $adly, not only do I lo$e dollar$ thi$ way, but I lo$e $torage capacity.

Two sets of sixes located in different sections isn't any different than two 12's located in different sections and that's pretty common in Class C's with limited space. Agree with Wa8yxm - compensate with heavy wire.

A guy here has a 3000w inverter on a beat-up pair of 6s on their last legs. He can run his microwave, etc, no problem for long enough. He has solar so the batts stay fairly full, which means they stay above inverter alarm voltage.

The OP didn't say he wants fast charging of both banks off grid. His converter will get them mostly charged on shore power in slow time, so he doesn't need fat wiring.

If he did want fast charging off grid he can do one bank at a time with a VEC1093DBD and not have to worry about his trailer wiring runs. Or both banks with two 1093s but needs enough generator for that, a 2000w gen should do two 40a VECs. (I think! Haven't tried it)

So IMO before the OP runs out and gets all that fat wire and changes his plan, maybe say more about what the camping circumstances will be. Might all work just fine as planned.

No problem pouting a 2nd pair at a "Remote" location.. Just use good heavy wire.

IF you have an inverter with a commma in the watts column, make it a very very very heavy cable

But if all you want is power for TV, Computer Appliance control (Fridge, water heater, on gas) fans and lights.. A common Starter cable (4ga) will do fine..

Several years ago I encountered an individual who drove his luxury pusher down the coast.

(3) three way battery switches. Blue Sea.

"When I want to charge just the engine starting battery I select both on the first switch. # 2 on the second switch and # 1 on the third switch. When I want to use just the generator starting battery, I select both, then # 1 and off on the 3rd switch. Or is it the other way round (Canadian speak)? HONEY! Grab the vehicle manual out from beneath the dinette set would you please?"

I made a diagram. What do you think?

"I think I need a cold beer"

I agree with mena661/RoyB, find the space or make space right up front together is best.