Dual Battery setup, Fuse Info?

[Rath]

Hey guys, so I've got almost everything I need to install my second battery in my truck and start running power to the back sleeping area. The only thing left is to figure out what fuses to use.

My trucks alternator is 130A from the factory and I'll be sticking with that (I had thought about upgrading, but really I have no need)

My question is, what size fuses should I use? the factory wiring from the alt to the battery is 2 gauge, I also purchase 2 gauge to go from the starting battery to the isolator, then the isolator to the second battery. Fuses will be placed at each battery positive cable as close to battery as possible.

The length of wire from the main batt to the isolator is around 2 feet, then from isolator to second battery is around 10 feet.



TL;DR

130A alternator
2 Gauge wire all throughout
Start Batt - fuse - Isolator: 2 feet total length
Isolator - fuse - Second batt: 10 feet total length

What amp Fuses should I use?

 

[Sparksalot]

Mine has two identical batteries in parallel, also with #2 between them. GM put a 175 amp mega fuse at the primary battery.

 

[phxdsrtrat]

Look at Marine Bus Fuses. They come in 50 to 300 amps. Depending on what you are using for your second battery the typical mounting for them may work right on the battery.

-Curtiss

 

[M Rose]

I would go with a 100 amp fuse, or better yet a marine grade 100 amp
Circuit Breaker.

 

[Rath]

Thanks everyone. Circuit breaker would probably be the best route, honestly.

Hard to find locally but I'll see what I can dig up

 

[Middlemiss adventures]

I bought these resettable circuit breakers instead of going with fuses. They have worked well so far.

 

[Middlemiss adventures]

And a quick tip for cable of you haven't bought it already. I picked up a cheap set of booster cables and it was 1/8 the cost of wires

 

[Mike331]

Something to think about, if you might use your second battery to self jump start your rig, you need a fuse that's large enough to handle that amperage. And the only load you're trying to prevent from shorting is the battery it self. I use a single 300 amp Mega Fuse and holder. If your setup was in my rig, I would run the fuse in the 10 foot length of cable.

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