>> Decisions, decisions...
Tell me about it.
I'll check out the Bosche Cube Relays. Our cars use them, by the way, but I don't think any of them are as highly rated.
>> I use 2 relays rated at 40 amps each and wires in parallel.
Is that one per battery? Or one each positive and negative?
I understood the other wiring detail well enough, thanks.
>> An auto reset circuit breaker should NOT be used for this task.
I understand that an Auto Reset breaker can cause problems by repetedly reseting a shorted circuit.
>> A multimeter should be a very required tools ...
I'm looking into an upgrade of mine. We're getting serious, here.
>> A battery that is 75% discharged will indicate 12.0 volts.
Yep. I have a couple of charts with battery charge details. A also have a decent Hydrometer.
>> The special RV batterys deal with draw down better..
I'll be patching one of my three truck batteries into the trailers Deep Cycle battery system. I hope that doesn't add to my list of problems.
Thanks for your comments re: relay method vs the diodes.
I don't know how completely standardized 7-way RV connector cords are, but here's what I have:
Terminal Function color guage
1 Ground white 10
2 Brakes blue 12
3 Running Lights green 14
4 Battery black 10
5 Lft Stop/turn red 14
6 Rt Stop/turn brown 14
7 Auxiliary yellow 14
I couldn't find Amperage ratings for the pins of the 7-way connector, though they list them for 4 and 5-way connectors.
>> it wouldn't surprise me if it's no larger than 12 gauge,
>> so there would be no point in upgrading the truck.
The only point would be to minimize voltage losses over the length of the run. It's all about subraction - the less you subtract the more you have in the end. You could probably scale the wire in consideration of the bottle-neck effect at the connector and pigtail.
>> Using a diode setup would cut that voltage to the trailer,
>> as well as the voltage to the truck batteries, down to at least 13.6V.
>> can you get a photo of the box that resides next to the
>> drivers air seat with all the terminals and led's on it?
I suppose that you mean "LEDs"? We couldn't find any thing that fits that description. Essentially there's nothing near or around the driver's seat. Maybe it's somewhere else, like under the hood ?
What's the function of this box?
>> does your truck have the over head console with the switches for accessories?
Nope. We have a molded plastic gizzmo that serves as an overhead junk bin and CB radio surround. We also have a 3-way overhead cab light module. Nothing very complicated.