Need help picking hybrid inverter

[frosty1]

I'm a newbie but have spent last 6 weeks absorbing information here through a fire hose?. My primary goal was to have backup for critical loads during outages but also want to backfeed the grid (net metering). I estimate 5Kwh usage per day during outages. Here's where I stand now:

1. I have ordered 16 Lishen 270aH cells to build a 48V battery pack (13Kwh).
2. Solar panels should be delivered today (qty. 10 370 watt phono). 48.1 Voc, 9.3 Impp.

Now I need to pick out an inverter. Here's my list :

1. Outback skybox (5Kw) : Looks like it does everything I want. MPPT voltage range is 250-600V, so I would probably have to series all 10 panels ? Higher price than others, but UL listed and looks like good support.
2. Phocos Any-grid (5KW) : Not much information out there on this one, but about half price of skybox.

Others I looked at are Schneider, SMA, MPP.

Would appreciate your opinion on which one would fit my needs better or other issues I should look out for.

Thank you.

 

[SiamDrew]

Frosty1,

How did you make out with your selection for an inverter to complete your system?

I too am looking for an inverter with dual AC Outputs having one for critical loads during outages. So far I have found the highly praised Victon Energy - Multiplus ll has these options but this comes with a price.

Hopefully, you are able to find an inverter for your system.

 

[frosty1]

I decided on the Outback skybox. It looks like it does everything I wanted. Battery backup for grid down, grid tie to feed power (net metering). I wont know how it works for sure until I get it completed. Been waiting 3 weeks for county to approve my permit. I looked at Growatt and other cheaper ones, but needed the UL listing for grid tie approval. I will let you know how it works out. Should be powering up in a couple weeks. Will be without battery pack at first until I get the Lishen cells. Good luck with your system.

 

[Ampster]

I decided on the Outback skybox. It looks like it does everything I wanted.

I have been running a Skybox for two years now and it has served me well. Sorry I did not see this thread earlier to help your decision process..

At first I used it for backup and some load shifting using a 10-15 kWh pack of used Nissan Leaf Modules. Shortly after joining this forum last year I purchased 28 kWh of EVE cells and have been running the Skybox mostly in Maximum Independence mode.
Let us know as you begin your installation. I have learned some tricks along the way. There is occasionally some good information on the Outback Power user forum.

 

[frosty1]

I have started the installation. Here are some pics. I wired the disconnect switch and critical loads panel yesterday. If I had to do it over again I would use 6 awg instead of 4 awg. Couldn't find red and white in 4 awg so had to use tape. Just need to connect top of safety switch to 60 amp 2 pole breaker in main house panel.

 

[frosty1]

 

[Ampster]

Looks good. The disconnect switch is redundant with the breakers in both the main panel and the Skybox. Butbit may be required by code. What I found I needed was a bypass switch so I could take the Skybox offline and continue to power the critical loads. Your needs may be different.

 

[frosty1]

Looks good. The disconnect switch is redundant with the breakers in both the main panel and the Skybox. Butbit may be required by code. What I found I needed was a bypass switch so I could take the Skybox offline and continue to power the critical loads. Your needs may be different.

Yes, I wasn't planning on disconnect switch but saw that power company requires it. Also thought about transfer switch for critical loads and might do that in future. For now if skybox is offline, I can disconnect critical load wiring and reconnect to breakers in main panel. I am planning on just removing wires from breakers in main panel, use wire nuts to extend this romex over to critical loads panel.

 

[Ampster]

Yes, I wasn't planning on disconnect switch but saw that power company requires it.

In my jurisdiction the power company requirements are distinct from building codes. My power company does not care what goes on "behind the meter" as long as any generating equipment that backfeeds the grid is UL approved. California took that one step further and added CA Rule 21. Where are you located?

 

[frosty1]

I am in Ohio. Duke energy is my provider.

 

[Ampster]

I decided to make a separate comment about the NEC 120% rule about backfeeding a panel. It may apply to your main panel and your subpanel but until we know more about your local building code it is just a footnote.

Now the question is, what is the City, County or State building code that would apply?

 

[frosty1]

Its Butler county, but I dont think they have their own code. Just ohio code. You got me researching about 120 rule. First question I have is why 60A breakers in skybox? For 5kw at 240V, wouldn't that be 30A breakers? I need to see what ratings are on my main panel.

 

[Ampster]

First question I have is why 60A breakers in skybox? For 5kw at 240V, wouldn't that be 30A breakers? I need to see what ratings are on my main panel.

Because at full capacity with AC coupling that is what the Skybox could do at full throttle. You could derate it and use smaller wire from your main panel with a smaller breaker feeding the Skybox. That would also help with the 120% rule on the main panel. Your sub panel looks like it is fed by a breaker and depending on the busbar rating you might be able to leave that the same. I have no idea of an assymetrical set up would raise an inspectors eyebrows.

 

[Ampster]

. You got me researching about 120 rule.

I do not have it completely in my head so I did not want to quote it without checking. I think I understand it conceptually. The concept seems to imply that on a panel that is back fed the sum of all the breakers cannot exceed 120% of the busbar rating. Derating by using smaller breakers is what I think can work if someone is getting close. I did that on my critical loads panel by using 15 Amp breakers on some of my circuits where i knew I wasn't going to need all 20 Amps that the wire could carry.

 

[frosty1]

Thanks for the explanation. Since I wont be doing AC couple, I think I will feed Skybox with 2- pole 30A breaker so 120 rule us not a problem. Already have 4 awg wire ran, no problem with that. Did you have to use rapid shutdown feature?

 

[Ampster]

Did you have to use rapid shutdown feature?

No I assumed that I did not have to do panel level shut down because those panels were on a shade structure. I will need to connect the shutdown connections to a switch near the main panel to shutdown the inverter. You will need to wire a jumper to those connections if you do not use a switch.
I am in limbo with my permit because we are looking at other houses and if we find something I will move the system.

 

[Hedges]

Yes, I wasn't planning on disconnect switch but saw that power company requires it. Also thought about transfer switch for critical loads and might do that in future. For now if skybox is offline, I can disconnect critical load wiring and reconnect to breakers in main panel. I am planning on just removing wires from breakers in main panel, use wire nuts to extend this romex over to critical loads panel.

My disconnect switch is outside by meter so accessible to utility company.
I think later they decided people can do without it, but then utility would just disconnect everything by yanking the meter.

A bypass can be implemented with $50 sheetmetal interlock and a backfed breaker on the sub panel. The backfed breaker could go to grid side of fused disconnect. Then you can bypass the inverter and isolate its electrical connections. Be sure to wire neutral and ground as well so those aren't open circuit if inverter removed.

 

[Northernchateau]

I

I decided on the Outback skybox. It looks like it does everything I wanted. Battery backup for grid down, grid tie to feed power (net metering). I wont know how it works for sure until I get it completed. Been waiting 3 weeks for county to approve my permit. I looked at Growatt and other cheaper ones, but needed the UL listing for grid tie approval. I will let you know how it works out. Should be powering up in a couple weeks. Will be without battery pack at first until I get the Lishen cells. Good luck with your system.

I might ask where do you live? I live in upstate NY and called National Grid the other day to ask about a grid tie permit. I was told I 1st need to fill out an application and have one of their engineers come out and do an inspection of my place before they would issue a permit. That's fine but what the lady could not answer was how much is a permit and how long it was good for.

 

[Ampster]

....... called National Grid the other day to ask about a grid tie permit. I was told I 1st need to fill out an application and have one of their engineers come out and do an inspection of my place before they would issue a permit. That's fine but what the lady could not answer was how much is a permit and how long it was good for.

It is responses like that which cause people to want to find a workaround which does not involve buying power from the power company. In my jurisdiction only a building permit is required to add a system as long as that system does not backfeed the grid. I already have a cost effective grid tie system installed by a third party. My DIY system suppliments that system and allows me to take more advantage of Time of Use Rates. It also gives me backup for when the power goes out.