48V Battery Bank Wire Gauge

Bananassassin

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I'm wiring 4 12V batteries in series to make a 48V bank for my 48V inverter. I'm planning to use 4 gauge wire. However, given that it is relatively high voltage, is that gauge of wire unnecessary? Can I go with a smaller gauge and/or longer run? Thanks!
 

Jgb3

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What size inverter? How many amps can it pull? Mine will do 300 amps so I’m using 2/0 and depending who you ask that’s to small
 

Jennifer

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I run 4/0 on my 48VDC system, the price difference more than makes up for the reduced heat on the cables (I live in AZ and every bit of heat saved in the battery area helps)... go 4/0 and you'll never have to wonder if you are too small. Buy some Windy Nation Flex and a hydraulic crimper and make your own, it's a lot cheaper and is super fun. Yea I know it's a mess, it's temporary while I move into a toy hauler.. but the cables look good..lol

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Bananassassin

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I run 4/0 on my 48VDC system, the price difference more than makes up for the reduced heat on the cables (I live in AZ and every bit of heat saved in the battery area helps)... go 4/0 and you'll never have to wonder if you are too small. Buy some Windy Nation Flex and a hydraulic crimper and make your own, it's a lot cheaper and is super fun. Yea I know it's a mess, it's temporary while I move into a toy hauler.. but the cables look good..lol

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Jennifer

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It's a SUNGOLDPOWER 12000W unit. 48V split 240V.
:oops: 4/0 and if they made a 5/0 use that instead..... LOL.....

Go big or go home I always say.... do it right the first time cus it's a lot easier than after a fire, trying to talk the insurance adjuster into believing you pulled permits and had all the electrical signed off and they should cover the fire.
 

Bananassassin

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So clearly 4 gauge isn't overkill. Quite the opposite. Thank you for the illustrative pictures!
 

Jennifer

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So clearly 4 gauge isn't overkill. Quite the opposite. Thank you for the illustrative pictures!
Just as a disclaimer, I think the cable on my lap was 2/0 for another project but I sure feel better using 4/0 and the total loss of heat in the cables is super nice.
 

Bananassassin

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:oops: 4/0 and if they made a 5/0 use that instead..... LOL.....

Go big or go home I always say.... do it right the first time cus it's a lot easier than after a fire, trying to talk the insurance adjuster into believing you pulled permits and had all the electrical signed off and they should cover the fire.
Well I'm going to DIY the basic stuff but I have a good electrician that will be tying into the meter with permits and the whole 9 yards. I know my limitations. The mere fact that I have to ask these questions illustrates that I need help with the critical parts and a second set of eyes to review my work. I just don't wish to go the full hands off approach and I want to be intimately familiar with how the system works rather than a black box view of things. "How does it work?" I don't know, just don't touch it" haha
 

Jennifer

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So clearly 4 gauge isn't overkill. Quite the opposite. Thank you for the illustrative pictures!
When all else fails, read the manual/listen to the manufacturer... the link to the manual is below, nice looking unit.


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Jennifer

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Is a 150A breaker between the batteries and inverter too small?
My Schneider SW4048 DC switchgear has a 250 on it as it came from the factory and before that in the DC line I have a Inverter Class T slow blow 400 amp fuse as well (from when I was running a 12VDC system).

That said, I'm a newbie as well so you may want to see what others say, listening to me may burn down your house... 🤭
 

Bananassassin

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When all else fails, read the manual/listen to the manufacturer... the link to the manual is below, nice looking unit.


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4/0 it is. Thank you! Now I just need to get a second job to afford it :)
 

Jennifer

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4/0 it is. Thank you! Now I just need to get a second job to afford it :)

That's a $3,000 inverter, don't starve it for power by going cheap on cable.... let it breath, good plan... well done.

It can be a part time job, it's not really that much more..

Jen

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Jennifer

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And here you go... LOL... Will posted a video today and at the 7:20 mark or so he mentions he's using 4/0 cable on this monster 48VDC battery....

 

Bananassassin

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I think I may give that battery a shot, except the 13.4 kWh model. It also has the cables included which look long enough to get to the DC battery lugs on my inverter.
 

Jennifer

Electricity kills, think twice before acting.
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And here you go... LOL... Will posted a video today and at the 7:20 mark or so he mentions he's using 4/0 cable on this monster 48VDC battery....

Bananassassin

I think I may give that battery a shot, except the 13.4 kWh model. It also has the cables included which look long enough to get to the DC battery lugs on my inverter.

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LOL... this is the same person that was tearing up at the cost between 2/0 and 4/0 right? Ok Sybil.... go for it... LOL... I freaking knew you could afford quality equipment when I saw the price of the inverter, you couldn't bluff me with your wire woes... lol
 

Wellbuilt

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I would use the largest gauge wire you can fit in the lug on the inverter and work with
I used 2/0 for my 3600 watt inverter .
I would allso buy Premade cables with crimped ends, they just work better , it’s hard to crimp your own ends
Tight enough so they have equal resistance , and if your system will be inspected make sure the wires are UL listed .
 
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