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Wiring batteries in Parallel?


ZSK

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I just bought a 6x12 Enclosed trailer and I'm working on the inside of it. I installed a couple of lights and a 12 volt plug to plug my power inverter into. I have four batteries that were given to me and I want to wire in parrallel and just put a charger on them once in a while. They are all the same age, 12 volt, and rated 37 AH and about 4" x 6" x 12" in size. My question is what size wire will be adequate for wiring the batteries together? I was thinking 8 ga. would be plenty but I'm second guessing my self.
 


MAKG

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The batteries are irrelevant for wire sizing.

It's the LOAD.
 

ZSK

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1 or 0 ga. is overkill don't you think? The most load on the batteries would be two lights, two small fans, radio/laptop, and phone charger all on at the same time.
 

Will

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You won't need anything that large. With 8-gauge wire you could run 45 amps continously on a 15' run. That would be suitable for a 400watt inverter and a couple of lights.

USE THIS if you need to figure other currents. An inverter is about 85% efficient I think, so if you have a 175watt, it would draw about 200watts, or 17 amps.
 

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we have 3 deep cycles batteries at work an their hooked up with 6 guage wire..
 

Will

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we have 3 deep cycles batteries at work an their hooked up with 6 guage wire..
So--what are they hooked up to? You could run your wrist watch off of three deep cyce batteries until Gabriel blows his horn and you would need a wire the thickness of the veins in a drunk gerbils eyes to do it. Or you could hook them so a starter motor for a Cummins diesel and kill the batteries in a minute and that would take a 00 wire maybe.

His batteries are pretty small and he said he has an inverter and a couple lights.
 

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Just run 4ga. and be happy with it. If you ever decide you need more batteries, which probably means a bigger load, you wont have to waste your time replacing 8ga. with 4ga.
 

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8 gauge should be enough.

I'm fond of overengineering to a degree, so if it was me, I'd be running 4 gauge unless I expected to be running something serious off 'em.
 

Capt Jay

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Bigger is better. It's not a significant cost differance. Build it right the first time. 00 is overkill, 4 is fine.
 

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Ugh...

He wants to run a couple lights & crap off some small 37 AH batteries.

#10 wire would be perfectly suitable for this.

Hook them up like below to help equalize the power sharing between all 4 batts (connect the main power wires at the "O" posts)

o-o-o-O
O-o-o-o

(hopefully that makes sense)
 

LearjetMinako

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Run the 4ga across the batteries, and then run the leads to a fuse box. From there, you can go smaller, like a 8ga.
 

ZSK

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Ugh...

He wants to run a couple lights & crap off some small 37 AH batteries.

#10 wire would be perfectly suitable for this.

Hook them up like below to help equalize the power sharing between all 4 batts (connect the main power wires at the "O" posts)

o-o-o-O
O-o-o-o

(hopefully that makes sense)
That's how I ran it. I used #8 wire. I figured that's more than enough considering the wires on my power inverter are only #12.
 

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