I just learned a lesson today about solar inverters interacting with the grid. It’s kinda an advanced level problem, but it might help someone.

First let me explain how my system is setup. I have PV (solar inverters) that make 240v from solar panels. Ordinarily these inverters are programmed to wait 5 minutes for stable grid power before they will attach to the grid and blow power backwards thru your meter. If the grid hiccups or blinks, they will quickly drop off grid for 5 minutes.

I also run a battery inverter that provides my house with 240v all the time. It has an internal transfer switch and can drop the grid if the grid hiccups just like the other one... great.

But here’s where my system is different. I put my PV inverters on the HOUSE side of the battery inverter. That way they can continue to make power for me even when the grid is down. One of the settings that you can change is to make the PV inverter more tolerant of glitches in power and they don’t wait 5 minutes to start making power again.... they always make power. Matter of fact, they always make 100% full power if the line frequency is 60hz. The battery inverter can change the line frequency of the HOUSE side to 62hz and the PV inverters will smoothly ramp down their power. This is why they are more tolerant of hicups on the grid.

A few months ago, I rearranged my system because I was working on teh battery inverter and forgot to put the solar inverters back into grid tie mode. Today we had a bad storm and the main inverters were giving me all kinds of funky error codes after each power glitch... things like “short circuit detected on grid”. It finally dawned on me (thanks @MasterBrains ) that the solar inverter was confusing the grid voltage for the battery inverter. When you get these odd errors the battery inverter will never reconnect to the grid until you shut the grid power down for a minute or two.

I’ll have to reprogram the PV inverter to be back in “grid tied mode” tomorrow once this storm settles down. For now, I’ve just shut it down... not making much power with all these clouds anyway.

Getting a tractor unstuck from the mud

While we are on the subject here is some more info on extracting stuck equipment and vehicles safely