Sounds like home solar installation will want access to my home network. Is this solely for my access? Or also for third parties?

What’s typical here? To balance access and security/privacy? I have a cable modem. Then a WiFi/lan router.

Should I have Tesla connect to the cable modem? Or the router? Or should I get a second parallel router as a peer to my existing router - segregate solar from my other home devices?

I have 35 panels on top of my house (not Tesla) and it’s a lease. Why do they need IP connectivity? Do you have a smart meter from your utility provider? They may want to monitor kWh production. Just ask them why they need this, in detail. I run some home automation such as thermostat, garage door, home alarm, sprinkler system, pool, so if it’s for that reason I think you’re good. They’d probably let you connect it yourself, that way you type in your WiFi password yourself, and they don’t have it.

I’m guessing for statistics and monitoring. Perhaps for sw upgrades. Not sure if it’s for me or to allow direct access by Tesla. Trying to learn more and how people typically handle.

https://www.tesla.com/support/.../turn-on-your-system

I think you're getting one without batteries. If you did have batteries, I've heard that the system will not function properly without the connection.

It’s for monitoring purposes; I can check it myself with the app.

However, they didn’t need my home network. The inverter has a cellular transmitter/receiver.

My guess is EULA, they can data mine your use and production for whatever purpose they wish...

My best friend just had a similar issue. Their system monitoring was outsourced to somewhere like China. IIRC he told them that he wanted a completely enclosed system or the deal was off. I believe they capitulated and "found a solution" but I don't know for sure.

After further discussions, I decided to buy a second router.

I'll use my old router for the solar system. I'll set up the new router as a peer subnet for my existing home networked devices. Both routers will connect directly to my modem. This should isolate the solar traffic from my personal network and devices.

I'll need some cheap device to connect to the subnet with the solar system. Or maybe I'll just connect my phone to it.