EG4 3 Battery Server Rack Rating

[OilCan]

(Pre-Assembled) EG4 Enclosed Battery Rack | 3 Slot | Wheels Included

Discover the EG4 Storage Solutions 3 Slot Battery Rack with an enclosed cabinet design, lockable door, and vented panels for cooling. Easy access, mobile-ready with casters, and stackable. Constructed from heavy-duty steel and compatible with all EG4 Server Rack Batteries.

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They show the buss bar rating= 300amps. I have (3) 24VDC/200AH EG4 version 1 server rack batteries. Should the buss bar rating be based on the AH rating of the battery or not? In my case that could be up to 600 amps

thanks,

 

[FilterGuy]

The Bus bar rating should be based on the current that will be drawn from the batteries.

So... if you have a 3000W inverter, it could draw as much as 3000/24= 125A. I would fuse that with a 125A x 1.25 = 156A fuse: Round up to 175A.
The busbar needs to handle 175A

 

[wpns]

The Bus bar rating should be based on the current that will be drawn from the batteries.

So... if you have a 3000W inverter, it could draw as much as 3000/24= 125A. I would fuse that with a 125A x 1.25 = 156A fuse: Round up to 175A.
The busbar needs to handle 175A

Should he fuse the batteries at 100A each so they can't over-supply the busbar?

 

[OilCan]

The Bus bar rating should be based on the current that will be drawn from the batteries.

So... if you have a 3000W inverter, it could draw as much as 3000/24= 125A. I would fuse that with a 125A x 1.25 = 156A fuse: Round up to 175A.
The busbar needs to handle 175A

Thanks!

In my case I have two 3KW Growatt inverters in split phase config. My system is run mostly as emergency backup for critical equipment, furnace, freezers, refrigerators and such on a six circuit transfer switch, in that way we control the loading as needed manually. So it would seem the 150 amp fusing would be plenty adequate for a 300 amp buss bar as you have illustrated.

 

[FilterGuy]

Should he fuse the batteries at 100A each so they can't over-supply the busbar?

If the batteries have output breakers I don't believe there is a need to fuse the individual batteries. However, there is debate on whether fusing is needed if the batteries do not have breakers.

In all cases, in the case of a short, the BMS should shut down before a fuse or breaker pops. The debate is whether the BMS overcurrent protection is reliable enough to forgo a fuse or breaker. The BMS will work almost all the time, but is "almost" good enough? Will there be a BMS failure with the Fets fused on?

 

[FilterGuy]

Thanks!

In my case I have two 3KW Growatt inverters in split phase config. My system is run mostly as emergency backup for critical equipment, furnace, freezers, refrigerators and such on a six circuit transfer switch, in that way we control the loading as needed manually. So it would seem the 150 amp fusing would be plenty adequate for a 300 amp buss bar as you have illustrated.

Yes, 150 will probably work because your loads will probably never max out the inverters for an extended period.

 

[wpns]

If the batteries have output breakers I don't believe there is a need to fuse the individual batteries. However, there is debate on whether fusing is needed if the batteries do not have breakers.

In all cases, in the case of a short, the BMS should shut down before a fuse or breaker pops. The debate is whether the BMS overcurrent protection is reliable enough to forgo a fuse or breaker. The BMS will work almost all the time, but is "almost" good enough? Will there be a BMS failure with the Fets fused on?

If the 200AH batteries have breakers I’d imagine they are rated for 200A. Does he need to protect the busbar input below 300A?

 

[timselectric]

If the 200AH batteries have breakers I’d imagine they are rated for 200A. Does he need to protect the busbar input below 300A?

Overcurrent protection on the bus bars is covered by the output fuse/breaker.
Short protection on the bus bars is protected by the battery fuse/breaker.

 

[OilCan]

If the 200AH batteries have breakers I’d imagine they are rated for 200A. Does he need to protect the busbar input below 300A?

These version1 200AH EG4-LL use 200 amp BMS, the front panel uses just On/Off switch which I can assume switches an internal contactor of sorts likely solid state since it is silent. Version 1 does not have the front panel breaker like the version 2 models do but it does claim 250 amp short circuit protection internally. My battery group is currently fused ANL 150A which I will be converting to Class T to the inverters running less than 10 feet of #2 welding cable for each pole. Negative is bonded to ground.

 

[timselectric]

Negative is bonded to ground.

Why?

 

[wpns]

Why?

Indeed, why? Many inverters float the battery terminals and connecting them to ground might be bad.

 

[timselectric]

Indeed, why? Many inverters float the battery terminals and connecting them to ground might be bad.

Exactly
I'm trying to figure out what possessed them to think that it was a good idea.

 

[OilCan]

It's been a few years since I've read about it. In any event if you should have some type of internal fault or voltage leakage at the invert/mppt or other component, then that voltage is floating until you make contact. So why not?

Vehicle negatives are bonded to ground or rather chassis ground. What's the effect of catastrophic BMS failure internally in a battery, does grounding the negative side help or hinder....I do not know. Proximity lightning strikes feeding through PV cables among other posibilities.

No issues experienced as yet.

 

[timselectric]

It's been a few years since I've read about it. In any event if you should have some type of internal fault or voltage leakage at the invert/mppt or other component, then that voltage is floating until you make contact. So why not?

Vehicle negatives are bonded to ground or rather chassis ground. What's the effect of catastrophic BMS failure internally in a battery, does grounding the negative side help or hinder....I do not know. Proximity lightning strikes feeding through PV cables among other posibilities.

No issues experienced as yet.

Today's systems are designed to be floating.
So that ground fault detection works correctly.
Unless your installation manual specifically directs bonding, it shouldn't be done.
In fact, most manuals will specifically say do not bond the DC systems.

 

[FilterGuy]

In fact, most manuals will specifically say do not bond the DC systems.

I find that most manuals are unclear about grounding the battery lines. What is clear is that the PV line should not be grounded.

 

[OilCan]

Today's systems are designed to be floating.
So that ground fault detection works correctly.
Unless your installation manual specifically directs bonding, it shouldn't be done.
In fact, most manuals will specifically say do not bond the DC systems.

Well the Growatt SPF 3000 mentions none of that and not surprising since these are Asian designs. This model is not even a Listed equipment so most likely would not pass local inspection. In my case it is only being used for emergency backup and off grid. Appreciate your input, I would like to see a link against specifically grounding a DC system.--Thanks

 

[timselectric]

Well the Growatt SPF 3000 mentions none of that and not surprising since these are Asian designs. This model is not even a Listed equipment so most likely would not pass local inspection. In my case it is only being used for emergency backup and off grid. Appreciate your input, I would like to see a link against specifically bonding DC system.--Thanks

I don't have a link to your installation manual.
I'm pretty sure (it's been a while since I looked) that your manual does not say to bond the DC battery negative.
You have chosen to go against the manufacturers direction.
Hopefully, you won't regret this decision.
I can only offer advice, and wish you good luck.

 

[FilterGuy]

I don't have a link to your installation manual.
I'm pretty sure (it's been a while since I looked) that your manual does not say to bond the DC battery negative.
You have chosen to go against the manufacturers direction.
Hopefully, you won't regret this decision.
I can only offer advice, and wish you good luck.

Many mobile systems have battery negative to ground as well as AC neutral to ground. I have not heard of issues.

 

[Mkgough]

I have one, works great. Getting the wheels on the bottom is a pain, but nice case with 2 EG4LL and Lifepower in it, room for one more.

 

[timselectric]

Many mobile systems have battery negative to ground as well as AC neutral to ground. I have not heard of issues.

A system designed for mobile applications (like Victron), is designed for battery negative bonding. Because of the possible interconnection between the house and drive train battery system.

 

[FilterGuy]

Many mobile systems are built out of the of Growatt and other dynamic bonded inverters. As I said before, I have not heard about issues of the negative battery being tied to the chassis. (But that only means I have not heard about the issues.)

The manuals for these inverters have confusing warnings around the PV line that, once properly understood, say not to ground the pv lines. I am not aware of any that prohibit grounding the battery negative. (Again, that only means I am not aware)

.

 

[timselectric]

Many mobile systems are built out of the of Growatt and other dynamic bonded inverters. As I said before, I have not heard about issues of the negative battery being tied to the chassis. (But that only means I have not heard about the issues.)

The manuals for these inverters have confusing warnings around the PV line that, once properly understood, say not to ground the pv lines. I am not aware of any that prohibit grounding the battery negative. (Again, that only means I am not aware)

.

I can't say for sure on these cheaper AIO's , either.
I don't think that they have any ground fault detection/ protection, so it may not matter.
But, it's better to be safe than sorry.
The higher quality ones definitely do have detection built in. So, DC bonding would defeat the detection.
I have personally burned a few portable inverters, this way. (No isolation between input and output)
So, my advice is always don't, unless the manufacturer says to.

 

[Nan_wpg]

Victron’s wiring unlimited says to bond battery - . I understand they are mostly mobile but there are pictures in wiring unlimited specifically showing a stationary instal with bonded battery -.

Morningstar is another manufacturer that specifies this. And I believe some of the,Samlex inverter manuals also show battery - bonding.

 

[wpns]

I measured the battery terminals on my EG4 18Kpv which uses PowerPro batteries, and there's no real bias or AC/DC readings between the battery terminals and ground. My meter reads a decaying DC from 48-ish volts depending on how I connect it, and it's got a high input impedance, so I imagine it's just reading the battery intrinsic capacitance to ground (the battery cases are grounded). So that particular inverter probably doesn't care, but I wouldn't ground any terminal I'm not instructed to.

 

[OilCan]

I don't have a link to your installation manual.
I'm pretty sure (it's been a while since I looked) that your manual does not say to bond the DC battery negative.
You have chosen to go against the manufacturers direction.
Hopefully, you won't regret this decision.
I can only offer advice, and wish you good luck.

Here you go:

Growatt 3kW Stackable Off-Grid Inverter | SPF 3000TL LVM-24P

The Growatt 3kW Stackable Off-Grid Inverter offers scalable power solutions with high efficiency, perfect for independent energy systems and expandable configurations.

signaturesolar.com

I am running two for split-phase service.

As we approach solar max, it's doubtful how well manufacturers have protected our equipment from a Carrington event, so far only radio blackouts have occurred in the Pacific. At some point floating conductors become antennas.

Carrington Event - Wikipedia

en.wikipedia.org

So far everything on my end has been performing fine since 202.