Practical repurpose of second battery ?

[PPV_2018]

I was looking for some advice or ideas on what could I do with the second battery on a Tahoe PPV. Does anyone know what relays/modules are routed to the secondary battery (if any) from the factory?

I figure its intended use from the factory would be for upfitting, to power emergency equipment without drawing on the main battery but obviously in the civilian sector that isn’t really needed. So I’m wondering what should I do with it

Thinking about maybe doing a sound system, like amps and subs and wire it to the second battery?

What about setting it up as a ‘reserve’ battery in case the main battery fails.. Would that be possible? practical?

Would appreciate any input

 

[Sparksalot]

I was looking for some advice or ideas on what could I do with the second battery on a Tahoe PPV. Does anyone know what relays/modules are routed to the secondary battery (if any) from the factory?

I figure its intended use from the factory would be for upfitting, to power emergency equipment without drawing on the main battery but obviously in the civilian sector that isn’t really needed. So I’m wondering what should I do with it

Thinking about maybe doing a sound system, like amps and subs and wire it to the second battery?

What about setting it up as a ‘reserve’ battery in case the main battery fails.. Would that be possible? practical?

Would appreciate any input

You might look through the GM Upfitter guide to see if they were available with the isolation relay, and what the number is for it. In the gmt900 PPVs they were available with and without the relay. Thecopcar didn’t have one while theothertwin did. If I remember it was a common multipurpose relay used in a lot of GM vehicles. It had ignition sense to isolate the second battery when the engine was off.

 

[Doubeleive]

I was looking for some advice or ideas on what could I do with the second battery on a Tahoe PPV. Does anyone know what relays/modules are routed to the secondary battery (if any) from the factory?

I figure its intended use from the factory would be for upfitting, to power emergency equipment without drawing on the main battery but obviously in the civilian sector that isn’t really needed. So I’m wondering what should I do with it

Thinking about maybe doing a sound system, like amps and subs and wire it to the second battery?

What about setting it up as a ‘reserve’ battery in case the main battery fails.. Would that be possible? practical?

Would appreciate any input

commonly they are just connected in parallel

 

[justchecking]

Mine is set up so the primary passenger side battery is used for every thing. The second drivers side battery is only used for starting if the primary is dead. There is an isolation module that connects both only when engine is running for charging. If I need to start from the secondary battery I toggle a switch. Look up Hellroaring battery systems.

 

[PPV_2018]

You might look through the GM Upfitter guide to see if they were available with the isolation relay, and what the number is for it. In the gmt900 PPVs they were available with and without the relay. Thecopcar didn’t have one while theothertwin did. If I remember it was a common multipurpose relay used in a lot of GM vehicles. It had ignition sense to isolate the second battery when the engine was off.

Smart, I didn’t think to look through the upfitter guide. I skimmed through the guide and the only mention of anything isolation is this little bit when mentioning l electrical equipment:

“Isolated, Auxiliary 730 CCA, 70 amp-hour battery without battery run-down
protection for customer installed equipment. “

So then this means an isolation relay is in place, right? Or ..

commonly they are just connected in parallel

I guess that means wiring a sound system to the aux battery would be pointless, lol.

Mine is set up so the primary passenger side battery is used for every thing. The second drivers side battery is only used for starting if the primary is dead. There is an isolation module that connects both only when engine is running for charging. If I need to start from the secondary battery I toggle a switch. Look up Hellroaring battery systems.

Nice

Question. The isolator switch allows the battery to accept charge while the engine is running, but produces no output unless the switch is flipped, yes? Would the aux then act as the primary battery until you could replace the main or would you still have to switch it back over to the main for normal driving

Would you care to elaborate any further on your set up

 

[Doubeleive]

Smart, I didn’t think to look through the upfitter guide. I skimmed through the guide and the only mention of anything isolation is this little bit when mentioning l electrical equipment:

“Isolated, Auxiliary 730 CCA, 70 amp-hour battery without battery run-down
protection for customer installed equipment. “

So then this means an isolation relay is in place, right? Or ..

I guess that means wiring a sound system to the aux battery would be pointless, lol.


Nice

Question. The isolator switch allows the battery to accept charge while the engine is running, but produces no output unless the switch is flipped, yes? Would the aux then act as the primary battery until you could replace the main or would you still have to switch it back over to the main for normal driving

Would you care to elaborate any further on your set up

unless the primary battery is flat out bad (will not hold any charge at all) then you would only use the auxiliary battery to start it
the general rule of thumb is to use 2 new battery's of the exact same size type and age, so the chances of one just going bad out of the blue are slim
I just replaced both of mine yesterday at almost 5 years old

 

[justchecking]

Smart, I didn’t think to look through the upfitter guide. I skimmed through the guide and the only mention of anything isolation is this little bit when mentioning l electrical equipment:

“Isolated, Auxiliary 730 CCA, 70 amp-hour battery without battery run-down
protection for customer installed equipment. “

So then this means an isolation relay is in place, right? Or ..

I guess that means wiring a sound system to the aux battery would be pointless, lol.


Nice

Question. The isolator switch allows the battery to accept charge while the engine is running, but produces no output unless the switch is flipped, yes? Would the aux then act as the primary battery until you could replace the main or would you still have to switch it back over to the main for normal driving

Would you care to elaborate any further on your set up

Yes the aux would act as the main but if the main is really really bad it could pull down the aux over time. When my main went bad this summer on the 2011 I just flipped the switch to start for three days while AutoZone decided the old main was bad. It was under warranty and they kept testing it before that finally replaced it for free.
The switch could be placed in the cab but I just leave mine under the hood.

 

[PPV_2018]

Yes the aux would act as the main but if the main is really really bad it could pull down the aux over time. When my main went bad this summer on the 2011 I just flipped the switch to start for three days while AutoZone decided the old main was bad. It was under warranty and they kept testing it before that finally replaced it for free.
The switch could be placed in the cab but I just leave mine under the hood.

Nice

This is definitely on my to-do list

 

[Badge]

I’ve set my Yukon XL up with dual batteries and Redarc isolator and been happy for years. They work as a single battery TBH. The main battery runs things as normal, pivots to spare when volts drop to certain level. The Alternator will charge both batteries back up starting with main, then hits the volts needed and switches to aux. Make sure your alternator is the larger size to put out the needed amps. Agree it’s necessary to start out with two NEW batteries of the EXACT same type/specs. And, form experience, stay away from AGM as the voltage is “too” regulated and too low for the isolators set to expect higher low voltage cutout ranges. If I were to start over, I’d upgrade to a Redarc BCDC and inside cabin outlets. I also installed the emergency jumper wire and saved me a few times. I use my set up mainly to keep “beer and bomb pops” on hand 24*7 for long family roadtrips. It’ll run a fridge/freezer (with real compressor) left in the car in the heat of AZ for 2 days without issue. Never drained the batteries from the fridge; just kids leaving lights on, etc. Then again, I just hold the jumpstart button for a few minutes to join/charge main battery and start it up.

 

[Streborel]

Here's what I did with my 2007 (Cherry) LTZ. I wanted to power a dash cam that would not kill the batt when parked at the airport for weeks. I incorporated a 'Big 3' upgrade along with adding a second, new Aux Batt. 1 - Because I wanted to keep the batts disconnected when parked (so that BOTH batts wouldn't get drained) I installed an AutoIsolator (see that 2 big red insulators on top between Aux Batt and fuse box?). I triggered the AutoIsolator from the Main Fuse box 'Engine' fuse so that when the engine isn't running the AutoIsolator is 'open' and the 2 batteries are disconnected from each other and (duh) when the engine is running the 2 batteries and main alternator ARE tied together. This way, if the Aux Batt is drained I still have the Main Batt in good shape to start the engine and the Aux Batt will then be recharged. (To maintain equal and proper current flow when charging, the 2 batteries must be identical (or very close)). 2 - The conductor (wire) on the top right of the AutoIsolator runs through a 150A fuse to the Aux Batt Positive. The other conductor on top left runs up along firewall and connects to the factory installed fuse on the firewall at Main Batt where the factory cable from the alternator is connected. 3 - I ran an additional positive conductor directly from the alternator (with another fuse) to the same terminal on the AutoIsolator as the conductor that I ran to the Main Batt. 4 - To ensure ALL negative current is monitored on the Negative Current Sensor I ran the conductor from the Aux Batt Negative Terminal to the Main Alternator bracket. I then ran ANOTHER negative conductor from the same Main Alternator bracket across the top-front of the engine to connect to the factory installed Main Grounding lug located on the front of the left-side engine block; I didn't alter the original factory installed negative conductor to the Main Batt. Now, the 2 12V batteries are connected the way that I want. Now, 5 - I ran a (fused) wire to the Main Buss fuse that supplied my OBD port and pulled it's original fuse, now my OBD is powered from the Aux Batt, my dash cam is connected to the OBD port. Lastly, 6 - I powered all 12V interior power supplies (driver side, passenger side, and the one in the cargo area from the Aux Batt. I reckon this post is a bit long and it may be in too much detail.