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Question 18kpv Solar main with Grid back-up

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(@kzramos)
Posts: 5
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Forgive me if I'm not posting in the correct place.  I am looking to install an EG4 18kpv system with solar pv as the main source of power but want to tie to the grid as a back-up to the pv. I do not want to backfeed the grid, only use it to charge batteries or run critical loads in low production periods.  I've looked through the EG4 wiring diagrams and I'm unsure of the proper set up for this.  Any help or a point in the right direction would be greatly appreciated!

 
Posted : May 15, 2025 8:00 pm
EG4 Eric
(@eg4eric)
Posts: 381
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Do you want the inverter to only power critical loads or all the loads in case of the grid goes down?

 
Posted : May 20, 2025 5:02 pm
(@kzramos)
Posts: 5
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@eg4eric The inverter will power the entire home.  The system will basically be off grid, but I would like to connect a 125 amp circuit from my grid tied building as a back up to the solar.  The grid would never be backfed, only used to charge batteries or run the system in the event of lack of solar production.

 

 
Posted : May 20, 2025 5:22 pm
EG4 Eric
(@eg4eric)
Posts: 381
Reputable Member
 

I recommend going with either option 7a or 8a. To ensure that no power is sent back to the grid, you’ll need to enable off-grid mode on the inverter.

As for which wiring configuration is best for your setup, I suggest consulting with a licensed electrician to determine the most suitable and safe option for your installation.

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Posted : May 21, 2025 4:25 pm
(@kzramos)
Posts: 5
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@eg4eric Thank you!

 
Posted : May 21, 2025 8:05 pm
(@leesfunnyfarm)
Posts: 1
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I am using an 18kpv  inverter as an off grid system. PV array of 4 strings of 8 panels and 6 eg4 batteries in rack mount. I am set up to use a 12.5 kw predator gen. which I have not needed so far and the system is powering the whole house and left my shop on grid power. I had thought about using grid power to recharge if needed and someone at EG 4 said to run a separate breaker from my grid live panel and come into the 18kpv at the "Generator in" terminals.  I didn't do that because so far I have plenty of pv/battery power.  Its amazing.  We have had rain and overcast solid for the last 8 days and the battery is recharged  by noon every day from the unseen energy coming through the overcast skies. I am in Northern Minnesota.

 
Posted : May 22, 2025 2:49 am
(@kzramos)
Posts: 5
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@leesfunnyfarm That is awesome, thank you for taking time to share.  That is helpful!

 
Posted : May 27, 2025 11:12 pm
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