DC- DC

[liltex]

The shortest run to connect the house battery to the starter batteries is under the floor, about 20'
I have 1xs in all the valleys except where the pos. cable will be. 1/2" insulation then plywood sub floor.
Any problems with this route?
Will 2/0 wire be good?

 

[gnubie]

The expected maximum current flow is what you need to add into the mix when working out the wire gauge. Your layout comes into play too. Can you draw up a diagram of the distances between your batteries, the placement of the DC-DC charger, etc?

 

[liltex]

I planned on running the cable straight back out of the driver's seat pedestal ( tranist) to about mid floor then straight across to the passenger side and back to the top of the wheel well, about 20', I'll have my 2 200ah batteries in a box atop the wheelwell. They'll be a piece of plywood on the wall right there under the bed with the DC-DC, inverter and all the electrical. Sorry, I'm computer illiterate

 

[gnubie]

Do you know the amps that the DC-DC charger will be supplying to the batteries during charge? Are the batteries in parallel for 12v or series for 24v? Is your vehicle's battery 12v or 24v?

 

[liltex]

I don't know the amps the charger will be pushing, dual starter batteries in 12v, heavy duty alternator, the house batteries will also be in 12v. I haven't started any of the solar system yet. I've insulated and working on the floor now, then I plan on putting the bed in, then solar, trying to get at least the floor and bed in by spring.

 

[gnubie]

That's the rub unfortunately. Without knowing the current you expect to put into the battery any cabling you run will be a pot luck guess. It might be expensive overkill, or it might not be rated high enough resulting in overheating etc.

Do you have a particular DC-DC charger in mind? The manufacturer's web page will likely tell us its capabilities.

 

[Ped]

I have same kind of run. Down from bay along frame about 20ft. It had an 8awg and I simply added 4awg welding wire. Amp clamping from alternator to coach batteries with 20a flow theres very small current difference and I want to say about 1/10th of a volt drop. So im guestimating 2awg (not 2/0... thats enormous) is fine up to 40-50a.