auxiliary battery for new gmc pickup

enblethen wrote:
Second battery location is normally for diesels.
To use as an auxilary battery, you would need to isolate it. I donot care for diode based isolators. A more robust is using a relay such as these and wired per instructions. The coil of the relay would be wired to a location that is "hot" when the ignition switch is in the "run" position. Remember to install some type of fusing to protect the system.
Battery disconnect

My old 79 F250 Camper Special had a second battery isolated for powering the Camper, you could drain it dry, and still had the other for starting.

Diesels use both for starting,twice had to be jumped at the air port, 1st time sent a Ford Ranger took about 10 minutes to put enough charge in the batteries to get it to crank. The next time it happened, I asked them to send two!!

Another reason for this option is if you are running a snow plow or planning on doing adding a winch. My 2000K3500 came with the second battery installed but not hooked up to anything. One night I left my lights on so I switched batteries started up and went to work.
If I put in a replacement for it I will likely put in a deep cycle so I can have "extra" juice when dry camping.

My advice is to have a reason for adding a second battery or put the $$ in savings.

Paul

I've ordered my last 4 trucks with the auxiliary battery option. On my present one the battery cable runs from the power distribution block on the passenger side across the top of the firewall to a battery isolator and then on to the auxiliary battery.

The battery isolator isn't like the one pictured above. It looks like the starter solenoid for most riding lawn mowers. You need to make sure it's rated for constant duty and high amperage. The solenoid will have two large terminals across from each other and two small terminals for the energizing coil. The coil should be wired so it's only activated when the ignition is on.

I had a second location in my 98 Tahoe. At that time I pulled my little jayco popup and used the space to keep a battery charged all the time. When it got cold and the little furnace ran all night, I had plenty of juice to keep my young family warm. I used an isolator and it all worked well.

Moved from Forum Technical Support

I added the second battery to my '02 Chevy truck. I ordered the battery tray, relay, and wiring from the Chevy dealer at the parts department. The charge wire runs from the starter motor terminal up to relay and than to the the aux. battery positive. It comes heat wrap insulation where it runs near the exhaust manifold.
The isolation relay mounts to the firewall. There was already a connector there to control it. It was just a matter of plugging it in.
When the truck was on the relay allowed both batteries to charge. When the truck was off they operated independently. I used the second battery to power an inverter for my tools.
I think using the factory GM components is far easier and nicer than starting from scratch on your own. Don't use a diode isolator. An automatic charge relay (ACR) from Blue Sea would be my choice if I hadn't used the factory relay and it's already existing control wire.

Second battery location is normally for diesels.
To use as an auxilary battery, you would need to isolate it. I donot care for diode based isolators. A more robust is using a relay such as these and wired per instructions. The coil of the relay would be wired to a location that is "hot" when the ignition switch is in the "run" position. Remember to install some type of fusing to protect the system.
Battery disconnect

Are you talking about a 2500 or 3500 gas. Its most likely because the diesel has 2 batteries.

You need an isolator...RV places have them...they use them so a coach battery in motor homes dont go dead.



Isolator