2nd battery wiring question?

[Wesseat]

I currently have 2/0 running between my agm under the hood to my rear agm and superbank.. Im moving my batteries in the rear and need to gain some length in the 2/0 to make it happen.. I could run my 2/0 directly to to my 300amp alternator and gain the wire i need for the rear.. Is there any draw back to going straight to the alternator? I have 2/0 big 3 under the hood also. Thanks.

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[Dafaseles]

So, if o followed correctly, you'd be disconnecting the battery under the hood and going straight from the alternator to the batteries in the back?

 

[Wesseat]

So, if o followed correctly, you'd be disconnecting the battery under the hood and going straight from the alternator to the batteries in the back?

Yes

 

[Dafaseles]

Are you then planning on doing another run from the alternator to the under the hood battery? Or do you plan on doing a battery delete under the hood and moving the I've the hood battery to the back with the others?

 

[Wesseat]

Are you then planning on doing another run from the alternator to the under the hood battery? Or do you plan on doing a battery delete under the hood and moving the I've the hood battery to the back with the others?

i currently have 2/0 from the alt to under hood battery and and then 2/0 from the front to rear batteries. All i want to change is to move the 2/0 going to the rear battery over to the alternator.

 

[AnthonyO 10+ year member]

Someone correct me if I'm wrong.

You can do that, but I would use a battery isolator to do so. Alternator to isolator, isolator out to each battery

Amazon.com

 

[AnthonyO 10+ year member]

Or you can buy an NVX 500amp isolator. Leave the alternator to primary battery. Primary battery to isolator, isolator to rear battery. You will need a ground and and 12v ignition as well.

https://www.sonicelectronix.com/item-46583-NVX-BIR500.html?utm_source=google&utm_medium=cpc&utm_campaign=PLA&utm_source=google&utm_medium=cpc&utm_campaignid=15216902354&utm_matchtype=&utm_keyword=&utm_device=c&utm_content=183016435116&utm_devicemodel=&utm_network=g&utm_loc_physical_ms=1021504&utm_loc_interest_ms=&utm_placement=&utm_adposition=&gclid=CjwKCAjwopWSBhB6EiwAjxmqDf0Gzl4--neUOgXKQ4AOdwghucU_n17J8kN_qIp9tBLEEANiPCG5PRoC8_AQAvD_BwE

 

[Popwarhomie 5,000+ posts]

Yeah you can do that. Just make sure you still have a positive going from your alternator to your front battery positive. Have done it like that on two of my personal cars.

 

[Dafaseles]

To add to Pop, you would also end up losing however many amp hours you're getting from your under the hood battery to your amplifiers. Right now, you have all your batteries hooked up so essentially you have one big battery with a ton of ah. Uninstalling your front battery from the chain, it will only power the vehicle. Not the vehicle and the stereo. If you need it to maintain your voltage, that's just something to consider

 

[Wesseat]

To add to Pop, you would also end up losing however many amp hours you're getting from your under the hood battery to your amplifiers. Right now, you have all your batteries hooked up so essentially you have one big battery with a ton of ah. Uninstalling your front battery from the chain, it will only power the vehicle. Not the vehicle and the stereo. If you need it to maintain your voltage, that's just something to consider

But if i don't use a isolator the batteries would still be connected? But instead of being connected at the front battery positive it would be at the alternator so id still get the full amp hours right? I was worried it might be hard on my alternator or something... Every example i can find online has it wired like i have it now... Even if i leave it on the battery up front i can route it down the passenger side to gain the slack i need.. I was just being lazy

 

[Wesseat]

Yeah you can do that. Just make sure you still have a positive going from your alternator to your front battery positive. Have done it like that on two of my personal cars.

I do.. Is it less efficient like that or the same?

 

[Popwarhomie 5,000+ posts]

I do.. Is it less efficient like that or the same?

Would be the same as the batteries are still connected together at the alternator.

 

[Dafaseles]

But if i don't use a isolator the batteries would still be connected? But instead of being connected at the front battery positive it would be at the alternator so id still get the full amp hours right? I was worried it might be hard on my alternator or something... Every example i can find online has it wired like i have it now... Even if i leave it on the battery up front i can route it down the passenger side to gain the slack i need.. I was just being lazy View attachment 36961

You're right, I didn't think about it that way. I was thinking it would isolate the under the hood battery from the others. Sorry about that.

 

[Wesseat]

Thanks for your input guys!

 

[metalheadjoe 10+ year member]

I don't think others understand what you're trying to do, so here's my interpretation:

OP is relocating the aft batteries. His wire is not long enough to go from the front battery to the new battery location, but it is long enough to go from the alternator to the new battery location.

To OP: the only thing you are changing is the junction point between alternator and batteries. Nothing changes circuit-wise. Battery isolators are overused and have become a catch-phrase for people who don't understand their purpose; you don't need an isolator.