Dual batttery wiring question...

[Jeff@QuadShop]

What is the best way to run the negative wires in a dual battery setup? I've read that you go from the negative on the aux battery to the negative on the main battery then to engine ground. Do I also need to ground to the body like the stock battery was? I'm using 2 Odyssey PC2150's with 4ga cable and solid state isolator if that matters.

 

[MarcFJ60]

I don't have a definitive answer for you, but I'm not sure it matters. Whether you ground the aux battery directly to the chassis or to the other battery, they still share a common ground - i.e. the chassis. So it may be more an issue of practicality depending upon where you mount the aux battery. If you have a good chassis ground near your aux battery, why have a long run of cable back to the primary battery? Or vice versa, if your aux battery is adjacent to the primary why not just do short run to the primary especially since you know there's already a good ground?

That's my thinking. But don't be surprised if somebody smarter chimes in with better logic.

 

[Andy@AAV]

By the instructions from the National Luna Kit I installed, the auxiliary ground must go only to the main battery's ground. This keeps the aux negative wire from becoming an alternate ground route to the starter if a connection is loose in the primary wiring, which could cause the aux wiring or battery to overheat due to current flow.

 

[Jeff@QuadShop]

By the instructions from the National Luna Kit I installed, the auxiliary ground must go only to the main battery's ground. This keeps the aux negative wire from becoming an alternate ground route to the starter if a connection is loose in the primary wiring, which could cause the aux wiring or battery to overheat due to current flow.

Should I ground the main battery to the body and the engine like my stock battery was?

 

[1911]

Should you ground the main battery to the body and the engine like my stock battery was?

Yes.

 

[Jeff@QuadShop]

Yes.

Great, thanks!