Dual Batteries question

[2015TahoePPV]

Is there a way to tie the dual batteries together so the truck can jump itself?

There's a relay on the firewall that seems like its part of that system, but I'd rather not create a fire experimenting.

thanks!

 

[Sgt__Z]

Everything I have found on these forums shows that the two batteries are already linked, for the most part. Some PPV/SSV's have a relay in between to keep one battery from draining the other, and on the other side the two batteries act as one big battery. I know that doesn't help with your question but there you go. You could always just disconnect all of the wiring from your secondary and connect jumper cables from one to the other. Just hope you don't fully drain it during the jump process. Hopefully someone with more knowledge will answer.

 

[perpetual_student]

This might be the upfitter guide for your 2015 Tahoe PPV.

On my '18 SSV a battery isolator is used to separate the two batteries. TBH, I've only had my SSV for a week and haven't dug into the details quite yet, but typically the isolator keeps the batteries separate until the voltage of the main system reaches a set number. That number theoretically coincides with the main battery being charged. Then the isolator opens the circuit to the aux battery enabling it to be charged. That is a one way flow of electricity however, the aux cannot be used to charge or rather, drain, the primary battery.

I'm guessing that you could disconnect the aux battery (for safety sake), and then use jumpers between it and the primary battery to jump the car. And then reconnect the aux battery.

YMMV, IANAL, "insert your favorite disclaimer here." For example, this is the isolator kit I installed in my jeep to support a dual battery system that I use to drive a diesel heater.

 

[Q101ATFD]

I believe that the relay is set up so that they're isolated when the ignition is off. If the rest is wired correctly, all of the accessories run off one battery, and the other is used for OEM electronics. But when you have the ignition on, both batteries are connected which allows the truck to "self jump" if the accessory battery is dead. This ignition hot also allows both batteries to charge while the engine is running.