Florida ? hurricane Idelia and home backups

[Tim_in_FL]

Hopefully all other fellow Floridians faired as well as we did here in Windermere Florida and escaped with little but much needed rain and a small amount of wind. Being inland from the west coast of course helped protect us. However it was nerve-wracking just the same, as prepping for the hurricane my Generac 5550, generator that I would use for whole house supplemental power during storms would not start. At least at this point we made it through and we did not need the generator but that makes me turn my thoughts to a good off-grid battery system to use for such outages rather than high pollution gas and frustrating engine starts. We currently have 10.37 KW of Rec panels mounted on our roof, and of course if the power goes out the system shuts down at the inverter and even if it were sunny and producing power we couldn't even get a drop to use. We are interested in looking for a solution where I could take one string of our roof mount panels, and switch that over to an off-grid small inverter and Battery system Maybe 5 kilowatts similar to the 5550 that we would currently have. I'd be happy to replace my gas generator with a good battery system that would be reliable. Some questions of course would be what type of a system and how much I've had some companies out and of course they want me to scrap what I have and start over with the whole new inverter system batteries in most people talk Tesla and Powerball which I don't currently have and did not originally pick not to mention the price would be 20 to $30,000 and I already have an existing fully paid for system. What I'd really like to do is be able to take a substring, since I have three strings feeding to the solar Edge inverter, put that on a switch if that's available to do and have that string switch to charge the battery system to full and then switch back to the regular inverter so I get full use of my panels unless I need to charge the batteries.

So I throw this out as a question and a challenge I'm sure others have had, how can I retrofit battery system into my existing inverter or a smaller separate inverter system off grid to be able to use as I would the gas generator when the whole grid goes down. Cost is a factor of course or I would go with the 20 or $30,000 to replace everything. I'm not all that familiar with the latest inverters that can pull solar power to charge the batteries and then switch over to various options and features. Thank you in advance to anybody who has thoughts and ideas and can respond and recommend looking at various equipment to save a ton of money because I know it's out there and I know people have done this and I don't want to get rid of such a great Workhorse inverter that I have.

 

[Quattrohead]

AC couple your solaredge system into an EG4 18k or Solark 15k and buy 30kwh of batteries. Either of these inverters would charge your batteries during the day and act as a UPS during a power outage.
No messing with panel permits or changes to your home insurance, just put the inverter between the solaredge and your breaker panel. Pull a permit for that if you feel like it ?

 

[Tim_in_FL]

AC couple your solaredge system into an EG4 18k or Solark 15k and buy 30kwh of batteries. Either of these inverters would charge your batteries during the day and act as a UPS during a power outage.
No messing with panel permits or changes to your home insurance, just put the inverter between the solaredge and your breaker panel. Pull a permit for that if you feel like it ?

Yes, that was the same initial thought I had, but is it not possible to switch the 1 string of 4 panels to charge batteries from solar, instead of AC?
This thought was if AC down batteries could still charge during day, to keep supplying power.

 

[Tim_in_FL]

Ultimately, of course we would love to use the 64K batteries in our Kona EV, hopefully this can happen sometime soon.

 

[DIYrich]

Yes, that was the same initial thought I had, but is it not possible to switch the 1 string of 4 panels to charge batteries from solar, instead of AC?
This thought was if AC down batteries could still charge during day, to keep supplying power.

Don't move the string. Grid - eg4 - solaredge. The solaredge thinks the eg4 is the grid.

 

[Tim_in_FL]

Don't move the string. Grid - eg4 - solaredge. The solaredge thinks the eg4 is the grid.

Hopefully, I was explaining correctly. Not wanting to fool the existing solaredge inverter to think grid is still up, during power failure. Heard this can be a whole set of issues with a 10k+ solar system.
Want off grid to be able to run small room AC, fridge, network, few led lights, television, etc. To keep batteries charged thought to use 1 string if 5 REC panels 200w/each I think. Set this to switch to charge batteries when grid down or to charge batteries. Switch back to get maximum use of all panels under regular grid tie use.
Does this make sense? ?

 

[400bird]

The panels connected to your solar edge inverter have solar edge optimizers on them. These optimizers are required for the inverter to connect to the panels and harvest PV. The optimix are proprietary and only work with Solar Edge inverters.
So, no you can't easily disconnect one string from the solar edge to use on something else.

Using a second grid forming inverter is a good solution (that's what I did) alternatively you could get a Solar Edge Storedge inverter that would replace you current inverter, provide grid down power, and work with some specific batteries.

 

[Quattrohead]

Not wanting to fool the existing solaredge inverter to think grid is still up, during power failure.

It won't, the new inverter will shut down the grid side and hence the solaredge will too, but then the new inverter will battery backup your home.

 

[DIYrich]

Hopefully, I was explaining correctly. Not wanting to fool the existing solaredge inverter to think grid is still up, during power failure. Heard this can be a whole set of issues with a 10k+ solar system.
Want off grid to be able to run small room AC, fridge, network, few led lights, television, etc. To keep batteries charged thought to use 1 string if 5 REC panels 200w/each I think. Set this to switch to charge batteries when grid down or to charge batteries. Switch back to get maximum use of all panels under regular grid tie use.
Does this make sense? ?

Main panel - transfer switch - Inverter - sub panel with ac/fridge/etc

Automatic Transfer switch to select between Main Panel (grid) and Generator

Inverter has extra panels and battery.

Get Grid-Tied inverter if you want ability to export to grid from panel connected to inverter.
Otherwise, off-grid will work.

 

[Yurtdweller]

I have no experience with on-grid, but it still boggles my mind that these things are designed this way. If I ever get tied, I will probably design my system like a big RV. Bank charges off solar or the grid, with programmable parameters. House runs off the bank until it reaches a set low soc, then the house switches to the grid. This would also offset grid consumption by using solar-generated energy primarily. Expecting a storm? Charge the bank to full, then use the grid until/unless it fails. The bank would therefore be isolated, unable to backfeed. I think this may also alleviate the need for special permitting, and avoid solar use fees, no? I certainly will never allow myself to be forced to sell low, then buy back my own power at an increased price. Btw, I built a 14.5 kwh LiFePo4 bank for about $3,000 USD. I know that won't run a whole house for long, but it runs my tiny yurt home for a week. Of course, I have no climate control.