SolarEdge Daytime Solar Options during power outtage?

[Sunburnt]

I have the same (or very similar) equipment as other posters in this thread - SolarEdge inverter, 10kwH LG battery, etc — and recently bought a generator hoping to connect it to the same critical loads panel that the LG battery powers as my primary backup source when the grid goes down. My generator is just an inexpensive Costco Champion brand generator, so I don’t have any dreams of auto-failover. But this thread scares me with the tales of poor manufacturer support for what I’d consider basic (and promised) functionality. I don’t want to risk damage to the inverter or battery by running the generator. If I am willing to come out and manually flip a transfer switch, and then manually start the generator, shouldn’t I be able to do that without risking any of the solar equipment or grid? I assume I’d just put in the transfer switch disconnect between the inverter and the critical loads panel.

So, my use case would be: The grid goes down and the SolarEdge inverter automatically switches to LG battery backup until the battery reaches its low-level cutoff. Then the house goes dark and I go out and flip the transfer switch, flip on the generator, and go back to bed. Is there any reason that can’t work?

 

[darkskies]

I'm assuming you have the SolarEdge BackUpInterface (BUI) of which the battery and inverter are connected? The Solar Edge App Note for Generator Integration shows several scenarios, where the generator is connected between the panel and the BUI and uses a manual (for manually started generators) or automatic (for auto start generators) transfer switch.

From what it shows, it SHOULD run on solar/battery and then allow you to switch to generator (assuming you have it configured and have the latest software).

In my case, the generator is directly connected to the BUI, which is supposed to act as an automatic transfer switch. The benefit there, is supposed to be that, when the battery level gets to a configured level, the generator would turn on and power the main panel AND recharge the battery.

My system is configured this way (finally), but the installer could not test with the battery and simulate a grid outage. When the battery was swapped out (another long story), the installer told me it was all good to go. I wasn't sure how to simulate an outage, so I had no way to verify.

In the last outage 2.5 weeks ago, it switched right to generator, and did not use the battery, which was sitting at 100%.

I've been hounding the installer since, several times a week, to come out and troubleshoot the issue with SolarEdge (of which I opened a case). It sounds like the BUI cover can be removed and then internally disconnect (switch?) from the grid to test battery failover. When the installer gets here, I want to see how that is done and have them verify grid to battery failover, battery + solar operation with no grid, generator switchover when battery hits 20%, and generator charging of battery.

I'm not holding my breath - the installer takes FORVER to get out here.

 

[Sunburnt]

I think I do have the BUI, but from this thread it sounds very iffy that the SolarEdge firmware would work properly anyway. So I’m thinking an old-fashioned manual transfer switch is less money and less hassle. I admit having the generator charge the LG battery would be a great benefit if it worked…but that’s a big if. Also, my generator is not a pure sine wave generator so I’m not sure what the power it puts out may do to the apparently sensitive inverter/battery eldctronics.

 

[darkskies]

As I understand it, without the BUI, when the grid goes down, it will stop generating power from PV AND the battery. The BUI disconnects from the grid. The big question (in my case) is whether or not the firmware will connect battery to main panel, when there is no grid power. Right now, it flips directly to generator.

Previously, I (temporarily) had grid, battery, and PV connected to the backup interface, which supplied the main panel. Off the main panel, was a sub-panel with critical circuits and an ATS. When the grid went out, the ATS would trip and generator would power the critical circuits. That, unfortunately, was not using battery, when the grid was out.

I waiting to find out i the final solution will work in my setup.

 

[darkskies]

Update on my site...

About three weeks ago, we had a grid outage, and with a fully charged battery, the system instead of running off battery, went right to generator.

I opened a case with SolarEdge and contacted my installer. After a few days, SolarEdge responded and told me to have the installer come out, and in the interim, they were updating the firmware of inverter 4.19.36->4.20.32 (two revs newer). The release notes for 4.19.36 had indicated "seamless transition to backup", which is why we thought it would have worked previously, but it was not. I don't see anything in the 4.19.39 or 4.20.32 that mention anything about backup changes, but maybe it was a small change and not reported.

Today, the installer showed up and connected to the inverter. SetApp initiated another update, which updated the firmware to 4.20.36 (one rev newer). Again, I don't see anything in the release notes, about backup related changes. In any case, this is what we saw...

There is a pull switch on the BackUp Interface that disconnects from the grid. We had a mostly cloudy day, 42% charge on our 16 kWh battery, and the house load was close to 1kW.

Upon disconnect, there was about a 2-3 second delay and it switched to battery AND PV. As the cloud cover was fluctuating, it would switch from powering the house from PV to battery to both. Looked good, and the battery was actually slowly charging.

To simulate the battery hitting the low charge limit, the installer changed the configuration so that the limit was a few percent below current charge. We then flushed toilets (well for water), ran microwave oven, turned on table saw, drill press, grinder, and a few other tools to start drawing down the battery. PV was bouncing between 500W and 2.5kW, so we were trying to draw more.

Eventually, it hit the limit and switched over to generator (I can't recall how fast, but seemed quicker than from grid to PV/Battery). Again, seemed to work well. The only issue was that, looking at the monitoring app on my phone it only showed how much PV was producing and that it all was going to battery. There was no indication of the house consumption, like I'd see if on grid, PV, and/or battery.

We were not able to test the system, when running on generator, switching back to battery at some point, once the battery is charged back up. It was late in the afternoon, and with the mostly cloudy sky, it would be hours before PV could recharge the battery, if at all today.

Grid was then turned on. It takes like five minutes to switch back to grid. Installer said that it monitors/tests grid power and PV, before switching to grid + PV.

Before leaving the installer set the configuration to switch from battery to generator, when battery is at 10% (factory min is 6%).

I reported back to SolarEdge, as to what happened and mentioned these comments/questions:

1. There is no reporting of consumption, when running on generator and that I expected that it would, since generator is tied into the BUI.
2. The generator powered the house, but was not recharging the battery, which their documentation indicates that it is supposed to do that.
3. I asked them what the charge level of battery would have to get to, in order to switch from generator, back to battery. It didn't seem to be programmable from SetApp, according to the installer.

So, 95% of what we expected to see was working. It was switching to battery on grid fail, and then to generator. The battery was getting recharged by PV. The big item is #2, whereas #3 is minor (assuming it switches back), and #1 is a nice thing to have, but not required.

 

[400bird]

Congrats! Glad it's finally working. Sad that it took nearly a year and a half.

 

[darkskies]

Congrats! Glad it's finally working. Sad that it took nearly a year and a half.

Actually almost 3 years since initial install (7/2021)!

Hopefully they will continue to improve the firmware to report consumption during generator backup, and can configure generator to charge battery as well as power house.