Help with purchase

[Ironman482]

Hopefully someone can steer me in the right direction, I have a 9k grid tied system that I want to add a battery backup system to , not having any luck finding a local installer to help with the project , but I want to go ahead and buy a battery and hybrid inverter to have on hand in case the world goes to hell , I'm looking at the big battery rino 2 battery and their lux inverter package 48v system , but also am considering the Schneider conext XW pro6.8 120/240 inverter instead of the lux , is this a good plan for a whole house backup system , I live alone and use a modest amount of electricity, also have a diesel welder/ generator that will be available for emergency backup.the existing solar is 40 panels 295w Trina with a enphase inverter with micro inverters on the panels ,so AC power into the enphase box if that makes a difference, thanks in advance for any help.

 

[sunshine_eggo]

IMHO, if you don't buy an inverter capable of AC coupling with your existing grid tie (GT) inverter, it's a pointless exercise.

Your grid forming inverter must be at least as big as your GT inverter. Any split phase inverter > 10kW output capable of AC coupling with a GT inverter will work.

40 * 295W = 11.8kW. If you're limited to 9kW, and you're over-paneled to 11.8kW, that's fine, but if your GT inverter can actually output 11.8kW, you'd need to size for that.

Alternatively, if you don't want to go >9kW, you could reduce the size of your GT array as needed.

 

[BentleyJ]

Since you mentioned whole house back up, Sol-Ark 15K can do 200A pass thru and could AC couple with the 9kW Enphase system.
Depending on the age and model number of the Enphase microinverters its likely a firmware upgrade is necessary so they behave well with the grid forming inverter. This is per recent posts on the forum by other members.

The Schneider XW Pro is a good product but a single unit is limited to a 60A pass through breaker and cannot handle 9kW of AC coupled power.

 

[Ironman482]

Thanks for the info , I'll see what's available in a larger inverter, enphase makes AC batteries which would be a simple solution, but they're expensive and low powered ,would need at least 3 and I don't think they're really ment for backup grid down use.

 

[Ironman482]

I hadn't looked at enphase AC batteries in a few years , it appears they've improved quite a bit since I checked into them 6 years ago , I think my best bet is to go with the enphase batteries, the cost is about the same and can get 10kw 3 battery system that integrates with the system I have with only the addition of a automatic transfer switch , now to find a certified installer, maybe the original company that installed my system 7 years ago .