ACC Setup Instructions
Yes, you can set the start or finish charge time with text messages. It would be nice to have a way to do it through the smartphone apps, but I imagine the UI would be a non-trivial amount of work to do well. It's pretty easy to do with text messages and you probably only need to do it once per charging location (home and/or work).
First, set/confirm you have the right time zone set. With a live connection, tap the Settings Tab, tap the ">" button, tap Control, tap Parameters. Scroll down to the last item, #23 and set it to your time zone offset. PDT is -7:00, EDT is -4:00, etc. While you're in there, you can also set the cooldown temperature, in degrees C, with parameter #15. The default is 31 (about 88F). I have mine set to 27 (about 80F), which may be too low in hot climates. (Don't mess with items #16 through #19, that's where the ACC parameters are stored in a compressed, unreadable, format.) Tap the "<Control" button at the top to save the change.
To verify that your time zone is correct, text the STAT command to your car. If the time zone is set correctly, the first line of the reply will be the current local time in 24-hour format.
Note that OVMS doesn't know anything about daylight saving time, so you'll have to change the time zone setting when DST turns on or off. If you don't, your car will start charging an hour later in the fall or an hour earlier in the spring.
ACC has a lot of options, which are documented in the user manual, but you can probably get it all set up with just three commands. The first step is to establish a location. Park your car where you want ACC to be active and send this command:
ACC HERE
That should respond and tell you which slot (1 through 4) is now associated with your car's current location.
Next, with the car still in the chosen location, set options using the ACC PARAMS command. For example, I have our car set to cool down whenever it's plugged in with the battery pack hot then delay charging so that will will be done around 7 am, limiting current to 32A and charging in Standard mode. All of that can be set with one command:
ACC PARAMS COOLDOWN CHARGEBY 07:00 LIMIT 32 MODE STA
After ACC is configured for a given location, it has to be enabled. This command will enable the car's current location:
ACC ENABLE.
That's it. You're all set up. A few things that may be of use later...
To disable ACC at the car's current location, so you can do a manual charge for example, send
ACC DISABLE
To disable COOLDOWN:
ACC PARAMS NOCOOLDOWN
To disable the CHARGEBY:
ACC PARAMS CHARGEPLUGIN
The full Roadster manual is here:
https://github.com/openvehicles/Open-Vehicle-Monitoring-System/raw/master/docs/OVMS_UserGuide_TeslaRoadster.pdf