I recently had an AIO with gateway installed and have an old, small PV (FIT) system. I liked the idea that the PV would continue to generate during a daytime power cut. Possibly a stupid question, but if our usage exceeds the PV generation (most of the time) and the AIO battery runs down to the 4% lower limit, will the PV generation be terminated as the AIO will go into an idle state? Although not sure if some of this 4% reserve will keep the PV on?
Monstercrew An interesting question.
The problem is that the PV FIT array is AC coupled and generates directly into the house, and of course all your house circuits are also connected to the house so the AIO has no way to differentiate between using its stored charge to supply the house or the PV inverter.
Moreover once the AIO reaches the 4% reserve it will stop discharging (as that’s the lower charge level) so at that point the AIO can’t supply anything to run the PV.
Your FIT array is presumably 4kW in size so in winter when you’re most likely to have a power cut it won’t be generating very much at all. My FIT array produced 1.17kWh today with a peak power of 0.55kW - not going to run very much on that!
In the event of a power cut especially a long one it’d probably be worth turning things off if you can to save the AIO battery.
Yes, once the AIO is flat, solar inverters won't be able to startup again.
Not sure if you can set the cut off value to higher than 4% (I thought they were getting rid of the cut off register, but perhaps not, as I've heard it mentioned recently).
Setting a reserve won't help AFAIK as the AIO during a powercut should discharge below the reserve.
Ultimately stop the discharge before it runs out, then start it again when the sun is coming up.
I did think solar had to be wired specifically to a certain breaker on the gateway, if you want it to stay up during a power cut, rather than just be on a household circuit. But perhaps it still works?
geoffreycoan Thanks. "Moreover once the AIO reaches the 4% reserve it will stop discharging (as that’s the lower charge level) so at that point the AIO can’t supply anything to run the PV." is what I suspected, and good to have confirmed. The PV array is only 1.4kW! but planning to add an additional (separate) array in the new year. As you say the plan would be to turn off things and aim not get to 4% if possible.
Has someone actually verified, if during a prolonged blackout, you can turn off AIO and Gateway to shut off power to the house completely, and then start it over again, and it will successfully wake up?
I was told that once the battery is flat, it will not restart no matter what, unless grid is restored.
I don't know if it can restore all operations when it's still charged, but still no grid.
bRhFDKtjRMK9 you can turn off AIO and Gateway
Well you can turn the battery off via its switch, and then the breaker, and then you could turn of the RCD in the gateway so that should completely disonnect the battery from the system
Or you could just lower the discharge rate to zero, many ways to achieve the same result.
TX200 Thanks, ah yes good point re the reserve, another automation to add to HA to stop the discharge instead :-)
Yes, the PV is wired to the Gateway and I've tested it stays working when the main incomer is switched off.
Monstercrew You would be better setting battery pause mode to PauseDischarge instead of/as well as setting the discharge rate to zero. I believe the AIO continues to discharge at 300W or so even if the discharge rate is zero’d, setting the pause mode drops this to something like 50W.
TX200 In a blackout scenario, if you reduce discharge to zero, then your house will go dark, including the network router. How will you tell the battery to wake up again, if there is no network to communicate?
CW Well you can turn the battery off via its switch, and then the breaker, and then you could turn of the RCD in the gateway so that should completely disonnect the battery from the system
Right. You can do that during the blackout to preserve battery level. But will it wake up successfully next day, and continue to operate with no grid? Will it, most importantly, accept PV generation next day, after shutdown?
Has someone verified this? I am very curious to know.
bRhFDKtjRMK9 have a mobile phone that has a hot-spot with the same name (ssid) and password as your main broadband.
Don't let the phone's battery run out!
Or have a UPS for your broadband router - switch it off to preserve battery overnight, then switch it on when ready to turn things back on again.
TX200 That's a very good strategy!
The only question remains, can we shutdown AIO + Gateway during blackout, and wake it up later like nothing happened, with still no grid, will it wake up normally and continue to discharge to the house + let PV generation work?