After a few more days, here is an update.
Charge on Solar continues to wake the vehicle every hour on the hour, even when excess solar is not available. From my 12V battery monitor, you can see this happening:
And what's really annoying is that if excess solar becomes available at a point between these wake-ups, it doesn't get used until the next hour. This graph is one I made of my Powerwall system. The batteries got fully charged at 13:30 but the first vehicle didn't start charging until 14:00. This vehicle needed only 20 minutes to reach the charge limit, and stopped about 14:20. But the second vehicle didn't start until 15:00 on it's next hourly wake-up cycle, and then charged for about 30 minutes. Had this vehicle needed more charging, the wasted time from 14:20 to 15:00 and also the delayed start of the first vehicle from 13:30 to 14:40, means nearly 50 minutes of excess solar went to the grid instead of the vehicle.
But what is most concerning of all this is how they implemented a new "key" for the Powerwall to access the vehicle. I do not understand why Tesla did this, as ChargeHQ does not need a "key" to access the vehicle, only a token for the Tesla API.
This Powerwall "key" is what is waking up the vehicle every hour, and it shouldn't be doing that especially since the Powerwall knows when it has excess solar or not.
On top of that, and even more significant than any of the aforementioned problems, is that this "key" UNLOCKS the vehicle!
Every hour when the Powerwall wakes up the vehicle, it is
UNLOCKED and can be accessed until it goes back to sleep, even without a phone key or keycard. During a few of the wake-up cycles, I went out to the vehicle without opening the phone app or having a phone key or keycard with me, and I was able to open the door and access the vehicle.
While I keep my vehicles in a locked garage, this is completely unacceptable way to implement Charge on Solar. It seems Tesla just threw this together without much thought at all, and there are some very serious problems with it. If you are using Charge on Solar and don't park in a secure location, check to see if your vehicle is periodically unlocking. Activate PIN to Drive if you don't have that already turned on.
All these problems with what should be a simple and useful feature are sending me back to using ChargeHQ.
Tesla, if you're reading this, please forward the information above to the development team. They really need to address these issues!