30 ft of 4/0 copper welding cable length from batteries to inverter?

[3boysatbeach]

its expensive but, my system design requires batteries to be on other side of garage from the inverter and transfer switch which is a total of 30 ft total cable length run thru soffit to a distribution block for the battery rack. I understand ideally batteries should be closer to the inverter.

I have not bought an inverter yet but given all the research i have done so far:
1) if i use a EG4 18k, all the lugs seem to max out at 2/0 so do i unitap 4/0 to 2/0 at the lugs? is this the way to do this?
2) if i use a Solark 15k, it seems i can run 4/0 all the way to inverter

Appreciate any help on this in advance.

thanks.

 

[Crowz]

I know you said your design requires them to be apart like that but the a/c wiring loves distance while dc doesn't extended the ac to be closer to the batteries would be a ton cheaper and safer.

 

[Tomthumb62]

To double on what Crowz said, any reason you can’t run long AC wires instead? Why can’t the inverter be near the batteries? Not sure of how many amps you’ll be running through that 4/0 but if too many, you’ll have those nasty voltage drop issues, which could cost you to rewire again in the long run. Double runs of 4/0?

 

[3boysatbeach]

thanks for this; cost aside… i am hoping i can make this but am asking for input from you all.

AC is all installed already with 20 ft of 4/0 SER cables between the to transfer switch, main panel and meter; ready to go

if this is dangerous or not advised; i need to punt and build an extension to my garage maybe.

this is why i am asking.; rookie mistake maybe thinking that 30 ft of battery cable is ok?

 

[Quattrohead]

if i use a EG4 18k, all the lugs seem to max out at 2/0 so do i unitap 4/0 to 2/0 at the lugs?

Run 2 pairs of 2/0 as it has 2 sets of battery connections
The likelihood of you running those battery cables at full power is not great so you should be fine. It's not that a battery cable will melt the moment you overload it it's the amount of time they can take the heat before the insulation starts melting. This is why silicone wires are much smaller for their rated capacity.

 

[CoolWill]

Of course it will be cheaper to get the inverter closer, but at 30 feet the voltage drop on 4/0 will be negligible. At 200 amps it is 1.5%.

 

[3boysatbeach]

i guess worst case for me; is to REDO everything from whats been installed and run 30 ft of 4/0 SER to relocate the inverter and switch near batteries… arghhh.

 

[ericfx1984]

I'm not understanding why you wouldn't want to put the inverter real close to the battery and then run wire directly to whatever it is you're needing to power on the AC side

 

[CoolWill]

i guess worst case for me; is to REDO everything from whats been installed and run 30 ft of 4/0 SER to relocate the inverter and switch near batteries… arghhh.

If it's already done, I wouldn't worry about it. The voltage drop is almost nothing at that distance. If you load it down with, let's say, 200 amps, then 48 volts becomes 47.27 volts.

 

[3boysatbeach]

 

[3boysatbeach]

I'm not understanding why you wouldn't want to put the inverter real close to the battery and then run wire directly to whatever it is you're needing to power on the AC side

i chose to do it that way due to space constraints on walls where batteries must go; i pondered this alot and it may have been wrong conclusion

 

[3boysatbeach]

If it's already done, I wouldn't worry about it. The voltage drop is almost nothing at that distance. If you load it down with, let's say, 200 amps, then 48 volts becomes 47.27 volts.

appreciate the feed back… voltage drop being negligent… but is there any danger or other things to note?

 

[3boysatbeach]

Of course it will be cheaper to get the inverter closer, but at 30 feet the voltage drop on 4/0 will be negligible. At 200 amps it is 1.5%.

thanks for this...

 

[Tomthumb62]

Of course it will be cheaper to get the inverter closer, but at 30 feet the voltage drop on 4/0 will be negligible. At 200 amps it is 1.5%.

@3boysatbeach i think this is your answer. I didn’t run the maths because I didn’t know your loads, but 1.5% voltage drop is excellent. 3% or less is the goal.

 

[3boysatbeach]

@3boysatbeach i think this is your answer. I didn’t run the maths because I didn’t know your loads, but 1.5% voltage drop is excellent. 3% or less is the goal.

got it… thank you very much

 

[Tomthumb62]

thanks for this; cost aside… i am hoping i can make this but am asking for input from you all.

AC is all installed already with 20 ft of 4/0 SER cables between the to transfer switch, main panel and meter; ready to go

if this is dangerous or not advised; i need to punt and build an extension to my garage maybe.

this is why i am asking.; rookie mistake maybe thinking that 30 ft of battery cable is ok?

FYI, batterycablesUSA.com is my current favorite seller. Great quality, flat rate shipping I think $5 and great prices. They don’t sell on Amazon or eBay, so their overhead costs are lower. Shipping from east to west coast has averaged 5-6 days for me. You can select your required terminal lugs or bare ends. They sell by the foot but you can select by the inch to get perfect length cables. Excellent marine grade heat shrink and solid hydraulic crimps on the lugs.

Edit to say that if you have the tools to make your own crimps, it might be cheaper to buy a 100’ roll but it will be same color for positive and negative, so be sure to install a foot of appropriate colored heat shrink on the ends and maybe every few feet a couple inches to mark which is which. NOT a place you want to hook up reverse polarity!

 

[Zapper77]

18kPV accepts 4/0 DC battery cables...with some room left over.

 

[3boysatbeach]

so… thanks everyone for feedback…

so back to my original question; if 4/0 at 30 ft for battery cable into the inverter is what I go with as discussed:

can i use a EG4 18k that has 2/0 lugs for AC and battery by reducing to 2/0 thru a unitap or block going into the EG4? rather than go with 4 - 2/0 cables which my change the distance math.

OR

use a SolARK 15k which seems to take 4/0 lugs in for AC and battery?

any thoughts which way to go?

 

[3boysatbeach]

18kPV accepts 4/0 DC battery cables...with some room left over.
View attachment 160066
View attachment 160067

awesome! so 4/0 cables in 18k work… THANKS for THIS.

 

[Zapper77]

awesome! so 4/0 cables in 18k work… THANKS for THIS.

Officially 250 Kcmil fits...but you would need to use ferrals for sure on 250 Kcmil.