Today I put the finishing touch on my split parallel battery setup. I don't boondock a lot, but when I do, I do. One, maybe two weeks in the woods going to town every now and then so I can get cell signal. Only way to live.
On my TT I had a steel battery box that held three batteries. Well with the 5er front bin so big I had to go with four, nice evenly split system.
This is two batteries in parallel, positive to one side of a switch, two more on the other side of the bin positive on the other side of the switch. Four gauge cable, copper lugs soldered on the ends of the cables and heat shrinked.
Tomorrow is the test, I've got a 1200W inverter that I used to run a TV for the ex, now it will power my CPAP machine. The CPAP is supposedly about 140W which will be a roughly 12A drain. I'm going to setup and measure the actual draw on the system, by the numbers I'll have more than enough capacity for two batteries overnight, but will need to sort out a charger I think. I'm going to experiment some tomorrow and see.
Anyhow, here's a few pics. Hope you like what I did with the place!
The cables between the batteries are equal length on both pairs to make them behave more like one battery, note the posts are opposite each other, makes equal length leads easy.
Here's how I grounded it. I thought I had more star washers, for now it's good with one.
Here's the layout, two on one side, two on the other. The cables and the vent hoses are run across the top and tied in with the factory harness. The blue wires are for an overhead light and will be rerouted now that I'm happy with this and the positive cable will be tied down with cable mounts.
My switch. It has batt one, batt two, both and off. It's a starter amperage rated piece from an ambulance, I've had it 12 years now and it works awesome.
My vent hose solution. I teed the two boxes together, using 1 1/4" plumbing tees from Lowes. I put a zip tie on to seal it off then ran a screw through to hold the hose in place. These two are tied together, then the hose is run across the top of the bin tied to the harness, then forward and teed into the factory hose just behind the wall vent. Both sides are set up the same. The battery cable will be tied to the wall now that I'm happy with the results.
That's it. I'm actually quite pleased with the results, rock solid, should give years of trouble free service and is quite simple to access.
I've got one more thing I'd like to do with this project. Add some jump start lugs like race cars use so that way I can independently charge one pair while the house runs on another pair. I'm thinking of Making a bracket and adding them in next to the switch. One ground, two positives on a bit of metal. I'll sort that out later!