48 vdc 200 AH Battery cables

[Ben3361]

Hi,

I would like to know what wire gauge you suggest from my batteries to my inverter.

8 feet of cables required (2 x 4 feet distance from batteries to inverter.)

2 x EG4 batteries 24vdc 200AH in series to a Growatt SPF 3000TL LVM-ES inverter (off-Grid)

Thanks in advance

 

[John Frum]

2 in series is 48 volts, is your growatt a 48 volt all_in_one?
3000 ac watts / .85 conversion factor / 48 volts low cutoff = 73.529411765 service amps
73.529411765 service amps / .8 fuse headroom = 91.911764706 fault amps

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baymarinesupply.com

That means 6 awg pure copper wire with insulation rated for 105C and a 100 amp fuse.
Since the eg4 units have a built in breaker you don't need another fuse.
Will you have any other components?
Will you have busbars?
A shunt perhaps?

 

[Ben3361]

No, straight to the inverter.

 

[John Frum]

No, straight to the inverter.

should be sweet.
Just to confirm it is a 48 volt all_in_one?

 

[Ben3361]

Yes

 

[John Frum]

Yes

If you don't mind my asking why didn't you get 2 48volt eg4 batteries?

 

[Ben3361]

I have 2 x 24vdc 200AH EG4 batteries which I will connect in series.
I want to be 100% electric. No propane. Also were in stock!

 

[John Frum]

With 2x 48 volt in parallel you would have the same capacity and you would have fault tolerance.
With 2x 24 volt in series if you lose one you are in the dark.

 

[Ben3361]

Understood but my system is based on 48vdc. Do you have a wire gauge to suggest ?

 

[John Frum]

Understood but my system is based on 48vdc. Do you have a wire gauge to suggest ?

I already did.

 

[John Frum]

6 awg is the minimum I would go with 4 awg.

 

[Ben3361]

Thanks for the suggestion

 

[Bossrox]

Me personally, I'd go #2. Best way you can tell if you have adequate wire size is feel your cables under a heavy load, if they are more than lukewarm, they're straining to pass current & that will lead to wire fatigue.

 

[timselectric]

I personally use the biggest lug and wire that will fit.
In DC power distribution, bigger is always better.