How is a EG4 Battery grounded without rack?

[HSN]

The EG4 battery manual: ● Step 3. Electrical Installation 1. Grounding wire. Affix a grounding wire of sufficient wire gauge from the battery module enclosure grounding screw (located on the front panel) to the rack frame (or cabinet) earth ground point. Ensure the connection is secure and corrosion free.

How is the battery grounded it's not installed in a rack?

 

[Solar Guy Richard]

There is a grounding screw on the front of the unit.

 

[HSN]

Do you run a ground wire to the inverter's ground screw on its chassis?

 

[Solar Guy Richard]

Do you run a ground wire to the inverter's ground screw on its chassis?

Yep!

 

[HSN]

Very grateful, thank you for quick response.

 

[Michaells]

@RichardfromEG4: I have seen a picture of an older model LiFePOWER4 with grounding screw but mine do not have anything that is clearly labeled as such. Please see the image attached and advise. I have 4 batteries in a rack with bus bars.

Also, I assume can run the ground to my house EGC (which is adjacent to the battery rack). Yes?

Thanks in advance.

 

[timselectric]

Each battery is connected to the rack with 4 screws.
Just ground the rack and the batteries are taking care of.

 

[knexbuilder]

Thank you @timselectric . I had the exact same question as @Michaells . I did notice on assembly that the battery flanges were not anodized on a couple of sides and that bare metal was left for what appeared to be grounding purposes. I verified with my multimeter that the battery housing is indeed bonded to the frame.

One question though. If I tie the rack frame to an earth ground does this also give the battery a potential reference for zero? I may not be asking that question correctly. Thanks for your help.

 

[timselectric]

Thank you @timselectric . I had the exact same question as @Michaells . I did notice on assembly that the battery flanges were not anodized on a couple of sides and that bare metal was left for what appeared to be grounding purposes. I verified with my multimeter that the battery housing is indeed bonded to the frame.

One question though. If I tie the rack frame to an earth ground does this also give the battery a potential reference for zero? I may not be asking that question correctly. Thanks for your help.

It needs to be connected to the AC grounding system.

 

[Sundown]

Yep!

@TheBestDIYGuy Ungrounded batteries cause error 61?

 

[timselectric]

@TheBestDIYGuy Ungrounded batteries cause error 61?

No

 

[Brightside]

"1. Grounding wire. Affix a grounding wire of sufficient wire gauge from the battery module enclosure grounding screw (located on the front panel) to the rack frame (or cabinet) earth ground point."

I have 12 of these 48V 100Ah batteries that are not in a rack and are sitting on a wood frame. I'm going to daisy chain the ground wire to each battery and then 1 wire to ground.

What is the "sufficient wire gauge" to connect the battery cases to ground?

I have lots of 14AWG ground wire, is that sufficient? As it it just a protective earth.

 

[timselectric]

What size AC input/ and or output breaker/s do you have?

 

[Brightside]

Each battery has a 125A DC breaker. AC breakers are 200A main and 200A load on a SolArk 15k. I have #4 AWG copper running with the mains.

 

[timselectric]

I wouldn't use anything smaller than a #10.
If something shorts out, the breaker needs to trip before it burns in two.

 

[Shimmy]

My read of the code is you would need to use #6AWG copper to bond everything together. (NEC 250.122)

When you parallel the batteries and use a 300A breaker then you would need #4AWG minimum. And, if you oversize your DC wires you end up needing to oversize the bonding conductor.

But, my interpretation doesn't pass the "gut" test.

 

[Brightside]

What parameter dictates "sufficient wire gauge"?

"If something shorts out", are you talking about a battery shorting to ground or AC?

Seems to me that the ground connection is just a protective earth, as the battery output is floating relative to the case, so there is no ground reference for the battery.

 

[Danke]

This is the first I have heard of grounding the batteries. Does Will ever address this?

 

[Brightside]

My read of the code is you would need to use #6AWG copper to bond everything together. (NEC 250.122)

When you parallel the batteries and use a 300A breaker then you would need #4AWG minimum. And, if you oversize your DC wires you end up needing to oversize the bonding conductor.

But, my interpretation doesn't pass the "gut" test.

Right, that's what I'm thinking.

I have 1200AH of battery, each with a 125A breaker. Each battery has a M6 ground screw. So ground size is based on one battery breaker? Or all 12 125A breakers paralled? It would be a big ground.

What do people ground their 6 battery EG4 racks with?

 

[timselectric]

If something goes wrong inside the inverter. And AC power is conducted to the DC side. And if it finds its way to the battery case. It needs to trip the over current protection, before damage or injury occurs.
I know that it's a lot of if's, but that's what safety is about.