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EG4 18Kpv system on 400 amp service?

Randman

New Member
Joined
Aug 21, 2023
Messages
3
Location
Mississippi
I have a 400 amp service to our fairly large house. I have ordered a system with the 18Kpv unit and 14kwh wall battery. I know the 18Kpv has a 200 amp limit.
So I'm planning to create a 200 amp sub panel with specified circuits that would work under that limit. And then connect the inverter directly to that sub panel. The remaining circuits would remain on the 400 amp main panel and be fed only by the grid for now.
Does this sound like it will work?
 
Yes, What you described is a typical configuration. The 18Kpv AC Input can be fed by a 200A (or less) breaker in from the 400A main panel so you have utility pass-thru and back up battery charging if solar is insufficient.

Keep in mind the transfer relay in the 18Kpv is rated at 200A for utility pass-thru but the inverter can only supply 12KW (50A) when utility power is lost. If the critical loads subpanel has several large appliances attached A/C units, water heater, elec range etc. you may need to practice some manual load control or perhaps install a Leviton or similar smart panel that can be programmed to shunt trip some of the less critical loads so the inverter doesn't get overloaded when operating on battery and/or solar only.
 
Yes, What you described is a typical configuration. The 18Kpv AC Input can be fed by a 200A (or less) breaker in from the 400A main panel so you have utility pass-thru and back up battery charging if solar is insufficient.

Keep in mind the transfer relay in the 18Kpv is rated at 200A for utility pass-thru but the inverter can only supply 12KW (50A) when utility power is lost. If the critical loads subpanel has several large appliances attached A/C units, water heater, elec range etc. you may need to practice some manual load control or perhaps install a Leviton or similar smart panel that can be programmed to shunt trip some of the less critical loads so the inverter doesn't get overloaded when operating on battery and/or solar only.
Is there a good diagram for this?
 
I haven't completely fallen off the face of the earth, and just wanted to quickly update (and ask another question). I'm just at electrical rough in stage but I think I've worked out how to setup the 2x18KPVs I'll be utilizing. I will actually backup the whole 400A service (using the same layout as EG4 has in their latest manual, except with 200A breakers in the Grid Input Combiner Panels.

I think I can utilize the Leviton "Smart" Load Panel (it's actually the optional breakers that are smart, not the panel) to do programmable load shedding as the Leviton Whole Home Energy Monitor (LWHEM-2) which is the "connected hub" for the Load Panel has a dry contact to "alert" the monitor, when power is out. To do this, I am hoping I can use the Generator Start/Stop (appears to be dry contact) on the 18KPV as the trigger for the "grid down" dry contact input on the Leviton Whole Home Energy Monitor. Any thoughts on this/why it may/may not work?

Thanks!
 
To do this, I am hoping I can use the Generator Start/Stop (appears to be dry contact) on the 18KPV as the trigger for the "grid down" dry contact input on the Leviton Whole Home Energy Monitor. Any thoughts on this/why it may/may not work?

Thanks!
I think the dry contact doesn't close until the inverter wants generator power to recharge the battery. Don't know if the 18kpv has a setting that allows it to be used as a grid loss signal.

Easy to hook up a relay that looses power and opens/closes when the grid goes down.
 
I think the dry contact doesn't close until the inverter wants generator power to recharge the battery. Don't know if the 18kpv has a setting that allows it to be used as a grid loss signal.

Easy to hook up a relay that looses power and opens/closes when the grid goes down.
LOL. I love it. KISS solution. I'll do that instead!
 
I haven't completely fallen off the face of the earth, and just wanted to quickly update (and ask another question). I'm just at electrical rough in stage but I think I've worked out how to setup the 2x18KPVs I'll be utilizing. I will actually backup the whole 400A service (using the same layout as EG4 has in their latest manual, except with 200A breakers in the Grid Input Combiner Panels.

I think I can utilize the Leviton "Smart" Load Panel (it's actually the optional breakers that are smart, not the panel) to do programmable load shedding as the Leviton Whole Home Energy Monitor (LWHEM-2) which is the "connected hub" for the Load Panel has a dry contact to "alert" the monitor, when power is out. To do this, I am hoping I can use the Generator Start/Stop (appears to be dry contact) on the 18KPV as the trigger for the "grid down" dry contact input on the Leviton Whole Home Energy Monitor. Any thoughts on this/why it may/may not work?

Thanks!

I have the Leviton w/LWHEM-2, but not the 18Kpv (yet). I have the same intent. With the Leviton, there is a normally closed contact that is used to trigger the designated "non-essential" loads to be shut off. You will need the smart breakers for those loads, obviously. Reading thru the EG4 manual, it should be possible to set the 18Kpv to trigger the "generator start" at a battery percentage -- like 20% -- signalling the Leviton to load shed.

I see less about triggering a "generator stop" once grid is restored, but that doesn't mean it won't do it. You'd need the 2nd Gen smart breakers with the Leviton for that to work. The 1st Gen only switch off remotely, whereas the 2nd Gen can also be remotely turned back on. For the record, they aren't cheap. :)
 
Still haven't finished the 2x18KPV setup but have a few more questions/potential bumps in the road.

So, has anyone considered not using the Manual Transfer switch? I know I lose out on the "Grid Only" power but it potentially cuts out, quite a few pieces of equipment. No Feeder Taps, (hence no Feeder Tap Breakers), and possibly, the Main Service Breaker would in one switch, serve as the PV System Disconnect since Grid is 100% fed through the 18KPV. I would use a (dedicated) 400A Load Center as my Input Combiner Panel, and then 1 (dedicated) 400A Load Center as the Output Combiner Panel, where all the House/Garage/Suite Panels would then be "sub-panels."

Any thoughts on this?
 

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