Dual batteries

[884x4310ci]

I have a dual battery set up on mine. That I took out of a diesel truck. Very simple set up. 1 wire from the starter to battery. 1 wire from battery to battery. Both grounds to go the block.
The truck I took it from had the wires joining the battery hooked to the fuse box that's in the hood of newer trucks. Long cable that goes from passenger battery over the far shroud to fuse box. Then a other short that goes from the same stud to the drivers batery. My truck don't have the fuse box in the hood. So I just when From battery to battery.

 

[SUBURBAN5]

I have a dual battery set up on mine. That I took out of a diesel truck. Very simple set up. 1 wire from the starter to battery. 1 wire from battery to battery. Both grounds to go the block.
The truck I took it from had the wires joining the battery hooked to the fuse box that's in the hood of newer trucks. Long cable that goes from passenger battery over the far shroud to fuse box. Then a other short that goes from the same stud to the drivers batery. My truck don't have the fuse box in the hood. So I just when From battery to battery.

So for my 98..


I know its confusing bare with me lol. Using my son's color and quick draw up

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[Supercharged111]

Strange. My dually has a solenoid and a long wire wrapped around the ABS pump and redundantly connected to something. It was defeated when the passenger battery was deleted. It makes me think GM didn't wire them as simply as has been described so far. I never have seen a schematic that shows this piece either. The solenoid is mounted to the fender back by the power distribution box. I too have had excellent luck with single batteries, but I do remember having less luck with batteries in general back when I lived in upper MI. One thing duals are good for is if the batteries are weak or freeze, you have a little extra to help you fire it off. Or if you have a hard starting POS.

 

[Steven Petersen]

I have a dual battery set up on mine. That I took out of a diesel truck. Very simple set up. 1 wire from the starter to battery. 1 wire from battery to battery. Both grounds to go the block.
The truck I took it from had the wires joining the battery hooked to the fuse box that's in the hood of newer trucks. Long cable that goes from passenger battery over the far shroud to fuse box. Then a other short that goes from the same stud to the drivers batery. My truck don't have the fuse box in the hood. So I just when From battery to battery.

Can you possibly take a pic or 2? Thanks.

 

[Supercharged111]

Can you possibly take a pic or 2? Thanks.

I figured someone would ask, truck is 20 minutes away but yeah, I can get pics at some point. I wonder if it was wired so you could kill one battery with the key off, preserving the other one until the key came on so it'd still start?

 

[Knuckle Dragger]

Strange. My dually has a solenoid and a long wire wrapped around the ABS pump and redundantly connected to something. It was defeated when the passenger battery was deleted. It makes me think GM didn't wire them as simply as has been described so far. I never have seen a schematic that shows this piece either. The solenoid is mounted to the fender back by the power distribution box. I too have had excellent luck with single batteries, but I do remember having less luck with batteries in general back when I lived in upper MI. One thing duals are good for is if the batteries are weak or freeze, you have a little extra to help you fire it off. Or if you have a hard starting POS.

I think you are describing a battery isolator. On some applications they want to run accessories off one battery with the engine off but have the safety of not being able to drain both batteries to the point the vehicle will not start. With the key on the solenoid will connect the two batteries in parallel, with the key off the solenoid opens to keep them separate.

2008-2014 Police Tahoes are setup without an isolator, 2015+ have the isolator. Either setup is good if you understand what you have.

 

[b454rat]

My Yukon had a dual battery setup when I first got it. Was from Wrangler or something like that. Had a 169 amp alternator I think. It had a solenoid and a switch under the column to switch back n forth then an emergency for both batteries. This had a serious stereo system in, and a metric **** ton of lights, so prolly needed the extra juice. I took it off when I first got it, sits in my basement.

 

[Postmech]

My buddy added an extra battery to his work truck to run his inverter to charge his 18v drill batteries without having to run the engine. Had it wired to a constant duty relay triggered by an added oil pressure switch to charge it. Just info.

 

[GoToGuy]

I can send some factory parts prints, and schematics. The battery trays left and right are in production by many aftermarket companies. My 93 k1500 one tray right side. My 95 k2500 two trays left and right. The 98 Tahoe, two trays left and right, the left tray has a factory snap lid storage box. Diesels have two batteries in parallel to push high torque starter. Camper optioned or heavy fleet commercial were often optioned two batteries with isolater for 12 volt driven add ons, without drawning down primary battery. Not required to run separate power leads from battery each startet. Power lead from left battery over fan sroud radiator to right battery pos' then to starter. How many amps (current) does your starter normally draw?

 

[454cid]

Interesting topic. I've kicked around the idea of adding a second battery, but basically put it out of my mind when I got the storage box instead.... stole it out of my dad's old truck before it was sold

I would have thought my truck would have had the 2nd battery from the factory since it has the snow plow prep package according to Compnine, but it does not.... only one.

I've heard many times that replacing both batteries at the same time is important, because one can run the other one down if one won't hold a full charge.... the good one keeps trying to charge the other one. I have no idea how valid this is, Though.

I've also been under the impression that they were normally wired with some kind of isolatior, but maybe that's only typical when adding a second battery later.

For now my solution is to keep a battery charger on my single battery, to keep it topped off. I'm not driving the truck right now.