Connection question, dual 6000XP's connected to 30KW (6 & LL-S 48V)

[ecmb52]

Hi Guys.

I purchased 2 6000XP inverters with a server rack & 6 / 5kw EG4 48V LL-S batteries. Can you help me verify 2 connections? FYI, This system will power essential circuits (refrig, chest freezer, well pump) and will be on its own panel! The rest of the house will be in the original main panel.

#1. All the batteries are connected in parallel. IE, all of + are connected to the positive bus and all of the – are connected to the negative bus. For the battery connection to the inverters, I simply connect each +/- wires to the corresponding bus and then the other side to the inverter. To verify, each inverter battery wire comes from the same bus. 2 runs, one to inverter 1, and the other inverter 2.

#2 AC Grid connection. The inverter manual refers to 8AWG inputs from the grid (house panel). 8AWG is rated for 40Amps. Each inverter requires an AC input. So I need 2, 2 pole 40 amp breakers in my house panel. 1 for each inverter. Is this correct?

Any input is appreciated!

Will post pictures once complete.

 

[solarenvy]

#1. All the batteries are connected in parallel. IE, all of + are connected to the positive bus and all of the – are connected to the negative bus. For the battery connection to the inverters, I simply connect each +/- wires to the corresponding bus and then the other side to the inverter. To verify, each inverter battery wire comes from the same bus. 2 runs, one to inverter 1, and the other inverter 2.

Correct. You can also run +/- from the rack to separate bus bars (placed closer to the inverters), then shorter runs from there to each inverter. That can reduce duplicate runs of expensive battery wire (depending on the distance from your rack to inverters).

#2 AC Grid connection. The inverter manual refers to 8AWG inputs from the grid (house panel). 8AWG is rated for 40Amps. Each inverter requires an AC input. So I need 2, 2 pole 40 amp breakers in my house panel. 1 for each inverter. Is this correct?

I sized my breakers to support the full 50A grid pass-through. So 50A breakers and 6AWG THHN wire.

Reference: https://diysolarforum.com/threads/dual-eg4-6000xp-wiring-please-review.78087/

 

[TM48]

In order to use the entire pass-through you would have overloaded the inverter.

 

[ecmb52]

Thanks for your responce, much appreciated!!
Please help me understand pass-through. I'm assuming this is grid current passes to the inverter from my main (IE 50AMP, 6AWG THHN)?
So the pass-through, 50amps is used when the inverters get overloaded?
When calculating my essential power requirement for my load, I never went over 40amps but from what I understand now the inverters get overloaded below the 50Amps (per inverter) correct? I have 2 6000xp inverters in parallel, what is the max load before overload?
Looking at the 6000xp manual, I think its 25AMP per inverter? So 50 total?

 

[TM48]

I too have two 6000xps. Each inverter would be overloaded at 25 amps. So two in parallel can supply 50 amps. I combine the two inverters in a small load center with 40 amp breakers. The output of that LC is a 60 amp CB. I sized the down stream wiring for three 6000s in case of upgrade. I could not see any condition requiring the pass through capability. This is an off grid system. The only time my inverters will be in bypass is when the batteries hit the low SOC value I've set. In the event of total system failure I have a grid bypass circuit in my house with a interlock to supply the critical load panel from my grid supplied load center.
On the input side the maximum current is 37.5 amps. This is 25 amps pass through and 12.5 for battery charging. Again #8 is adequate. Using #6 wouldn't hurt if you think you might upgrade to something else in the future but my experience has been that such decisions rarely pay off. Generally you end up redoing everything anyway. One exception is buried wiring.

 

[ecmb52]

OUTSTANDING, TY TM48!! Yes, the manual says #8 THHN (IE 40AMP 2P breaker) and thats what I wanted to use but so many people use #6 which confused me, why #6, 50amps.

This power source will be seprate from my main panel in the house and will be specifically for essential power (freezer, refrigerator, well pump) in its own panel therefore 50A or 60A is plenty but I do plan on monitoring the load and adding / subtracting circuits if capable. Eventually, once I have enough batterys and solar panels everything in the house will be on solar / batteries / inverters. But like you said most people will just rewire the system which I plan on doing.

 

[TM48]

I did the same. Started out with well pump, water heater, refrigerator, freezer and all lights I normally use each evening. Then after seeing that worked decided to add central a/c and it's progressed from there. Biggest mistake I made was not taking over my existing load center with solar and adding a new grid supplied one. It would have been SO much less effort!

 

[ecmb52]

For me I had to design a system inside my budget but yes a system to run complete panel would be much easier!

More help please -> I'm trying to figure out the neutral / ground bonding thing in the new essential power load center.
- I will need to run the loads (well pump, freeze, frig) from the main panel over to the new load center, Will I need to run the neutrals as well? Or will they be bonded back to the Main Panel?
-- The ground / neutral thing still has me confused! As I understand it the Inverter will need to be UNBONDED. Plan english details would be helpful. TY!!!