Accessing solar panel daytime power generation during power outage, best solutions?

[wstt]

I have a 32 panel system, EnPhase m250 micro inverters, live in Hawaii and generate 50+kwh on a sunny day, and only use like 25kwh per day. I have 1:1 net metering (grandfathered) and no batteries. How could I access the power during the day during a power outage, without adding a large cost? Could I add a tiny battery? Is this Sunny Boy inverter I have read about compatible and reasonable in terms of cost? What about the enphase iq inverters? If I just added a tiny battery would that allow me to access the power through it during the day and at night have no power? I only want to power fridges and lights mostly. And finally I've read some Car companies are going to allow EV batteries to power homes during a power outage. How would I be able to do that eventually? Thanks in advance for any guidance on this.

 

[ChrisG]

You will need a battery and inverter capable of AC Coupling (with enphase). Inverter cost $5-$8k and probably $2k-$4k for batteries to run it. Need more battery if power outage is at night.

 

[solar8484]

How long is the typical outage?
If you just want to power fridge and lights then a modest power station is likely significantly cheaper than any home battery system that works with your home solar system.

 

[Hedges]

There are several battery inverters that will AC couple to GT PV.
It works best if GT PV does frequency-watts, like Rule-21 for California. Not sure if m250 has that. IQ7 people have been using, and recently IQ8 firmware started working for AC coupled.

Enphase has their battery solution.
SolArk does it, recommended to put GT PV on "gen" port so they can be shed, also recommendeded to have DC coupled PV greater than AC coupled.

I use Sunny Island, with undersized battery mostly to let system operate daytime. That requires 2x battery inverters to make split-phase, or an auto-transformer. Pass-through relay good for 6.7kW per Sunny Island, not sure if your system is larger and would require two or if just one and auto-transformer would work (would also put all power through one phase, double the breaker size you presently backfeed.)

Maybe leave what you've got alone, and look into adding a hybrid with its own PV panels and battery. Wide range of prices, and battery is typically 48V but can be lower for small systems. Some use high voltage battery, typically expensive. Permits and utility permission to operate may require UL listed ESS and more expensive equipment, but since you're already known to export you may get away with not asking for permission.


A hybrid, or a Sunny Boy plus two Sunny island, or various others could work if you removed microinverters and wired as high voltage string. Maybe you are supposed to then install RSD (microinverter avoids that.)

 

[wstt]

You will need a battery and inverter capable of AC Coupling (with enphase). Inverter cost $5-$8k and probably $2k-$4k for batteries to run it. Need more battery if power outage is at night.

Don't my micro inverters already do the job of an inverter? Would there be way to have a manual switch to remove me from the grid and allow my panels to start working again? That way I could access their power generation during the power outage and when I see the neighbors power back on, I switch my panels back to accessing the grid? The prices you mentioned above, do or don't include installation? Why is everything so expensive for solar? Is the stuff really that costly to make?

 

[wstt]

How long is the typical outage?
If you just want to power fridge and lights then a modest power station is likely significantly cheaper than any home battery system that works with your home solar system.

Outages are normally 24hr, but I'd like to be prepared for several day outages.

 

[peakbagger]

Microinverters are sort of like the musicians in a marching band, they do their part but there still needs to be conductor setting the beat. Some master controller has to set the overall system voltage and frequency plus perform various system safety aspects. Once that is done the microinverters fall in line matching those values. That includes shutting down when needed if there is no demand, things can go poof if the panels are putting out power and it has no place to go. The easiest way is to have an intermediate battery to buffer variations between the amount of solar coming in versus the power demand.

I will note that Solar City did make a 6 KW string inverter designed to hook into a Tesla battery that was never sold in the US. Various individuals did successfully get the inverter to run without the battery. There are some you tube videos of these experiments. There is zero support on these units, Magnum actually built them but will not support. Solarcity got in financial trouble and the inventory of these were sold out as surplus. These units also had arc fault detection issues but there is workaround by disabling that function.

SMA also had a series of inverters with SPS which provided a limited output to a designated receptacle. I think it was 1000 watts max load.

IMO you need an off grid inverter with grid tie capability and batteries.

 

[wpns]

This keeps coming up, because it makes logical sense, but without a battery you were going to be really disappointed. Also, as others have pointed out there are a lot of hoops to jump through to get micro inverters to work when the power is out.

 

[solar8484]

Outages are normally 24hr, but I'd like to be prepared for several day outages.

How much are you willing spend?
Given that you just want to power fridge and lights (<1kW?) then a modest power station with a couple solar panels and potentially a small generator would still cost way less than any home battery or hybrid inverter system.