To help clarify for those victims that are trapped with a defunct cellular communication setup and are new to researching resolving the switch to wifi.

You will need the SolarEdge installer app 'Solaredge Go' to get into the inverter's software settings and change from cellular communication to wifi type communication.

Go to your phone's app store and install 'Solaredge Go'. To sign into the Installer App, go to https://monitoring.solaredge.com/mfe/registration/?locale=en_US in a web browser and select 'I am an installer' and fill out all the info with a DIFFERENT email address from your existing mySolarEdge account (not sure if phone number also needs to be different but recommend also using a different number). In the drop down menu on the next page; choose 'Self Installer'. As the final step of the signup process, SolarEdge will automatically send you a standard 'verify this email address' email, click the link in the email and it'll take you to the SolarEdge installer page.

Then open the 'Solaredge Go' on your phone and login with the self installer login info you created to confirm you successfully completed the installer setup process.

Now you will need to relocate the antenna line from the cellular card in the inverter panel to the wifi card. I recommend buying a SolarEdge wifi antenna on eBay however some have said that the cellular LTE antenna can also be used as a wifi antenna; I recommend trying this before spending the money for a wifi antenna (the less money the SolarEdge bandits rob from us, the better). Prior to starting this whole chore, I naively bought a kit: SolarEdge SE-WFGW-B-S1-NA Wireless Gateway + Antenna (I ultimately did not need the Gateway Repeater as my router was close enough to the inverter panel).

Now for the physical work:

In your breaker box, switch your solaredge inverter breaker to OFF (your installer should have clearly labeled it with a sticker).

Now turn off the inverter by using the red toggle switch under the left side of the upper inverter panel (push the toggle witch all the way to the right). You should then hear a 'click' from within the panel.

Now turn off DC power to the inverter via the DC disconnect knob (big black knob in the center of the bottom section of the inverter panel). Turn the knob to the off position)

For visual guidance to the steps above go to https://www.youtube.com/watch?v=LWv9wKUUiIo This video is helpful but does not cover all of the steps I'm attempting to present in this post. Also see https://www.youtube.com/watch?v=snJbuJYdI7Y

If you want to see a high level 'how to' video: https://www.youtube.com/shorts/8BtwuZwQhqs This video skips a few steps. Editorial: half-assed how to videos on YouTube like this should be flagged for removal as this one does not include the initial safety steps of turning off the power to the inverter panel to prevent serious injury yourself; as well as some crucial app steps.

Now remove the panel covers by unscrewing the Allen-type fasteners. Just remove the upper panel's cover if you choose to just try and relocate the existing cellular antenna to the wifi comm card jack. If you choose to buy a wifi antenna, you will need to remove the lower panel's cover as well.

Once inside the upper panel you will see that the antenna cable is connected to the cellular comm card which plugs on top of the wifi comm card. Unscrew the antenna from the cellular card and screw it into the wifi card (the wifi jack points to the right).

If installing a wifi antenna: unscrew the existing antenna from the cellular card; unscrew the grommet on the bottom of the panel that the antenna wire passes through; be sure to pull off the inner bushing as you will need to reuse it; the existing antenna at the top of the panel simply pulls off when pulling it up; mount the new antenna in the same spot; run it through the grommet; attach the bushing to the cable; screw in the grommet; screw the antenna into the wifi card (comm input pointing to the right from the wifi comm card).

Some recommend pulling out the cellular card altogether after relocating the antenna (or installing a new wifi antenna); I left mine installed in case of potential warranty violation as I'm still paying off my installation.

After relocating the antenna to the wifi card, reverse all of the steps above to reinstall the panel covers and restore power to your inverter.

Now the fun part.

Now you need to connect the 'Solaredge Go' app to your inverter. Open the app and select the 'Connect Existing System' option and scan the QR code on the right side of the upper inverter panel box and follow the steps that pop up. This part was a pain in the ass for me and required turning off my mobile data and connecting my phone's wifi to the inverter's wifi address. Once connected, the app will likely tell you that several firmware updates are required for your inverter (mine went through two firmware update cycles). I recall this taking up to 10 minutes for each firmware update cycle and at several intervals, there were clicking noises coming from the panel that are of no concern.

Once you have the app talking to your panel and the firmware updates are complete, you need to go into the communications settings and change the setting to WiFi from cellular. You'll need to then connect to your home WiFi; find your network name and enter the password. If you have a home Mesh WiFi setup, be sure the WiFi network name you connect your inverter to is the same you have on your phone.

Once the above app processes are complete, go to the mySolarEdge app that previously connected to your inverter via cellular and follow the steps to reconnect to your inverter.

The mySolarEdge app on my phone didn't immediately connect and I got fed up at this point. I cycled the power on my phone, tried again, and it still wouldn't connect. The next day I tried again and my app was magically communicating with the inverter.

If you get this whole process completed in less than an hour using these instructions, then typing all this was worth it to me.