Grounding 6 - EG4 LL V2 server rack batteries in a rack

[muaddib721]

I’ve been trying to find an answer on how exactly do you ground 6 EG4 LL V2 batteries in the rack. Do you run a ground wire from each battery to a lug attached to the rack and then ground the rack, or daisy chain the grounding lugs on each battery with the last one going to the lug on the rack, and then ground the rack? You would think the rack would be shipped with some sort of instructions. I know we have many folks in this forum using a rack of batteries so please post your grounding techniques it would be appreciated.

 

[pvgirl]

Use a star washer on one of the rack screws between the battery and the rack rail, this will bond batteries to the rack. Then attach a ground lug to the rack, be sure to clear the paint to insure a good connection, connect to ground system.

 

[muaddib721]

Use a star washer on one of the rack screws between the battery and the rack rail, this will bond batteries to the rack. Then attach a ground lug to the rack, be sure to clear the paint to insure a good connection, connect to ground system.

That makes a lot of sense… I posted the same question in the FB forum for EG4 users and the answers are all over the place. I wish the manufacturer or distributors would clarify what properly grounding means as referred to in the manual.

 

[timselectric]

I wish the manufacturer or distributors would clarify what properly grounding means as referred to in the manual.

It would be nice. But impossible.
It's different for different locations. You have to do it according to what your local AHJ (Authority Having Jurisdiction) wants.

 

[muaddib721]

It would be nice. But impossible.
It's different for different locations. You have to do it according to what your local AHJ (Authority Having Jurisdiction) wants.

I understand code will vary depending on jurisdiction but how to ground the batteries in the rack shouldn't vary that much. Basically there will be 3 options

1. No need to ground (some have argued on another thread I started on FB EG4 users group that its a closed system and doesn't need to be grounded

2. The batteries are grounded to the rack when you install them in to the rack via contact with the rack and then you run a ground from the rack to your external ground or to the ground in the system

3. Each battery should have a ground from the grounding lug on each battery to the ground lug on the rack and then run the ground from the grounding lug on the rack to your external ground or the ground in the system.

It's not an infinite amount of options...

 

[pvgirl]

I understand code will vary depending on jurisdiction but how to ground the batteries in the rack shouldn't vary that much. Basically there will be 3 options

1. No need to ground (some have argued on another thread I started on FB EG4 users group that its a closed system and doesn't need to be grounded=

This is gonna be a hard to justify option, if it's metal it should be bonded to the buildings ground system.

 

[timselectric]

I understand code will vary depending on jurisdiction but how to ground the batteries in the rack shouldn't vary that much. Basically there will be 3 options

1. No need to ground (some have argued on another thread I started on FB EG4 users group that its a closed system and doesn't need to be grounded

2. The batteries are grounded to the rack when you install them in to the rack via contact with the rack and then you run a ground from the rack to your external ground or to the ground in the system

3. Each battery should have a ground from the grounding lug on each battery to the ground lug on the rack and then run the ground from the grounding lug on the rack to your external ground or the ground in the system.

It's not an infinite amount of options...

It seems that simple. But you never know what any local inspector will accept. And it's understandable that nobody wants to be liable for guessing wrong.

 

[fmeili1]

This is how I've done it

 

[muaddib721]

This is how I've done it

View attachment 173986

That’s what I’ve decided to do. I just think the manuals should address grounding better. But it’s my experience that most manuals are deficient

 

[n2aws]

This is how I've done it

View attachment 173986

This looks good. I'd make sure you scraped off the piant between the "ear" on the battery, and the battery case itself. This will ensure that you have a solid ground to the battery case, not just the server rack ear.

 

[muaddib721]

This is how I've done it

View attachment 173986

what gauge wire did you use? I'm gonna go with some 10 AWG i have already

 

[fmeili1]

what gauge wire did you use? I'm gonna go with some 10 AWG i have already

Yes, it's 10 AWG and the short pieces were included in each of the EG4-LL (V2, 4-pin-DIP-switch) battery package.

 

[muaddib721]

Ok my fine forum folks I sent the same question to Signature Solar and they sent this reply

“As long as the battery bank is connected to the inverter properly and the inverter is grounded properly, the batteries and the rack themselves do not need any grounding wires as it will all be grounded through the negative line to the inverter.” ( see image of email )

 

[timselectric]

You've gotta be kidding me.
Another new guy, answering the phone. lol

 

[Balrog006]

The mounting ears for the battery to rack connections have a non painted face that makes contact when connected with the mounting screws . This grounds all of the batterys to the rack. Each rack has a ground (equipment grounding lug) at the bottom of the case by the door hinge where the door is grounded. Run your ground (EGC) wire from that lug with the star washer to your system ground.

 

[Sharing Society]

This is how I've done it

View attachment 173986

I would do this, BUT also run a ground from the top battery to your external and literal ground connection.

I don't trust the screw on the rack; it will be on a door opening and closing. That's not solid state. I would only trust a solid state connection.

NOTE:
I've seen a lot of old solar systems; and I've seen some places where fires have occurred. You want to ground properly for safety.

 

[fmeili1]

I would do this, BUT also run a ground from the top battery to your external and literal ground connection.

Yes, I've already done this (it's not visible in the picture). The ground from the top battery goes straight to the grounding lug in my wireway.

So the grounding enters rack on the top coming from the wireway, than hopping from battery to battery to the case and the last connection is the door.

I don't trust the screw on the rack; it will be on a door opening and closing. That's not solid state. I would only trust a solid state connection.

Me too.

NOTE:
I've seen a lot of old solar systems; and I've seen some places where fires have occurred. You want to ground properly for safety.

Because I would like to sleep with a good feeling and without fear of fire (the components are on the wall to our master bedroom), I took very good caution to ground everything with separate wires (cases, wireways, conduits, boxes, etc.). For safety, I've also installed disconnect relays and contactors between the battery racks and the AIO's, between the grid and the AC-in's and a module level PVRSS (via Tigo TS4-A-2F) and they will disconnect if one of the smoke detector will be triggered.
Better be prepared!

 

[Onehand]

So how are you supposed to ground the NON LL EG4 48 volt batteries? There aren't any ground points on them, unless the rack ears are supposed to do the job, think not...

 

[muaddib721]

So how are you supposed to ground the NON LL EG4 48 volt batteries? There aren't any ground points on them, unless the rack ears are supposed to do the job, think not...

Just ground the rack and you should be fine

 

[Balrog006]

So how are you supposed to ground the NON LL EG4 48 volt batteries? There aren't any ground points on them, unless the rack ears are supposed to do the job, think not...

That’s exactly how they are designed. They ground thru the mounting tabs and screws to the cabinet. It’s up to you if you connect that cabinet ground to anything.