Triple Battery wiring (check my thoughts)

[johnecon2001 5,000+ posts]

I just purchased a couple of Stinger SPV35's. I already have a PowerSafe 6VA7 under the hood (it's one of those deep cycles that are used in UPS's). I also have a 200A stinger relay.

Option #1

Do I take the alternator positive to the Relay. And then from one leg on the Relay go to the underhood battery, the other leg then goes to one battery in the back. And then go positive to positive for the batteries in the trunk.

Option #2

Almost the same as #1 except, I would take two runs of wire off of the one terminal on the relay and go to the two batteries.

Grounding will be one run from each batt to a common ground in the trunk.

So let me know which will be a better idea. Or if i'm even on the right track here. thoughts and ideas welcomed.

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[jrz126 10+ year member]

the only gain you will get is 2 runs of wire going back...which you may as well just run a larger wire.

You are running UPS battery under the hood? does that have the cranking amps needed?

 

[btnhfan 5,000+ posts]

I say ditch the relay

Connect the +'s together from the front to the back batteries, 1 run per battery.

Make sure you fuse all the + wires on both sides

Connect all the -'s together, and have 1 common ground under the hood

 

[johnecon2001 5,000+ posts]

I say ditch the relay
Connect the +'s together from the front to the back batteries, 1 run per battery.

Make sure you fuse all the + wires on both sides

Connect all the -'s together, and have 1 common ground under the hood

The only thing I saw in the relay was to let the system draw from the extra batts when the car was off so it didn't drain the starting one.

So basically I would take the positive from the underhood battery to the other two. and then take all of the grounds and couple them together, including the underhood one. So three runs of 1/0awg total, two positives going from the starting batt to each of the secondaries fuses on both ends of each run, and then one run going from the negatives on the secondaries to the starting batt.

the only gain you will get is 2 runs of wire going back...which you may as well just run a larger wire.
You are running UPS battery under the hood? does that have the cranking amps needed?

it has 800CCA. so I should be ok. Been working fine for a few months now. Something like 30Ah at 12volts too. I don't recall off the top of my head on that one, but the 800CCA is correct. A lot better than the stock 525.