Found out some more info on all this, and took another long drive and learned some tricks. First, when the car is plugged in, it does some work to maintain the batteries in a narrow temp range. If you remote-start the car, and have the other junk set up, it will warm the car cab up on house power, which is a good place to start (it will also run the defoggers). The heated seat doesn't use diddly battery power. The heater might if it's in pure-electric mode. The info screen says it can eat almost 20% of your range in full comfort mode (it has a try, but not too hard mode too, called eco that uses about half that).
In normal driving mode (of the three, normal, sport, mountain) you get an engine start with about 25% of the battery left. That's because the engine is only 84 hp, but the electric motor is more like 150 (267 ft lbs torque!). So you need to have some battery for peaks, or it would drive lame (it hasn't driven lame for me at any time, and that's why). "Mountain" mode "reserves" more battery in anticipation of a long grade climb coming up. The net effect of this is it will switch to gasoline at about half charge, and use both thereafter as needed. This can be used to get right about half a charge on the main battery even from "zero" by just driving it in mountain mode, which I did tonight - and I got 48 mpg doing that (engine running the whole time), and got home with half a charge - same as I began with (not running the climate stuff, it was nice out). Sport mode allows for more peak drive power, like you'd expect, but doesn't change the "reserve" for peaks like mountain mode does.
Looks like this thing probably gets 35-40 mpg on IC engine-only with climate control maxed out, from the discussions. That's a good bit better than the 34 the Cruze gets, or about 33 with the A/C on.
Other than climate control, stopping doesn't cost you anything - it turns off like any car. Idling - it doesn't do that, it just shuts off (the IC engine does too). Reheating the car after a stop (unplugged) would probably eat range. But plugged in, it will keep itself heated and so on from the plug power. And if some is left over, also charge. I get the idea that the heater is on the weak side in pure electric from the discussions. We'll see. It is in the Cruze, as is the A/C in that - just tiny stuff but still a car to heat, one step away from trying to condition the out of doors.
So the mountain mode is a kind of nifty hack that lets you keep at least 50% charge on the thing if you're demoing it all day - that's plenty to demo the pure electric mode, then put on mountain mode and the IC engine will get you back to half charge. I found that you can do somewhat better than that. I can come home from town more than one way, and the way I came you climb to the top of the mountain before coasting back into my place, and you coast for miles. With mountain mode on, you get regen braking doing that few mile coast, and it's enough to add a couple miles to the battery range from that.
Someone mentioned they get IC engine running at speeds over 75 mph. I just recently found the screen that shows all that (in the videos). Without that, you can't tell! They limit peak battery current, so the IC engine will cut in for super high speed cruising to help provide the vastly increased power need for going real fast and fighting the wind.
I found out IBM wrote this software - it's slick. A lot of people are complaining about the Ford stuff, which is Microsoft. Somehow, I'm not surprised.
This thing looks really well thought out so far - everything I've thought it should do, it already does, it's mostly a matter of understanding (or just finding out how to get it to tell you what it's doing now), maybe giving it a hint.
What I am surprised is that none of the demo vids I've found on youtube are even as impressive as my climbing of the hill from hell, and accelerating to over 75 doing it. And heck, that wasn't even in sporty mode -- I'm going to have to try to do a burnout in that mode with the traction stuff turned off. I have gotten the tires squealing on a hard left across traffic already, from a standing start - it really jumps off the line. This might just light them off and get me some smoke!
Since I got back home tonight with half a charge (burned a whole half a gallon of gas for the round trip in mountain mode, and not driving easy either, just my normal 50+ in a 35 zone), which is also about what I get from a decently sunny day, just turning on the charger *after* the house batteries are full in low use mode (stock trading with a computer and a light and the freezer/stereo running) - I should be able to get full charge on any good day, starting from there. Or two days starting from nothing (with my good panels still on the ground in the garden, where they are shaded most of the day). I suspect it's going to get better once I get them up in the air, a lot. I think this is going to work out great, and I'm planning on selling that Cruze, which I actually liked better than the Camaro as a daily driver. I just won't need it anymore (or the property taxes and insurance costs).
Oh, if it's dead cold - it's been parked overnight outdoors in 20f kinds of temps, it will always start the IC engine to heat the *batteries*. At that point, the cabin heat comes along free. But it looks smarter to keep it in a garage, and/or use the remote start and preheat off the house power (if you have it, in my case, nope). I'll probably put that coleman propane lantern in the back for preheat the cabin this winter or something like that. oohh, I have a neato wall mount gas lantern I'd bought for the van, but never installed, thinking "camping light and heat". It's cool looking and sips the propane. Now that would be a really anacronistic (but hey, romantic) touch in there...I even have a tiny propane tank (thanks to Bill finding it, unasked for) that will run it for a looonnng time - about the size of a big cantaloupe. And yes, Bill, they filled it the other day, no questions, leak tested it free for me. Cool! (or in this case, HOT).
Here's a link to a forum of owners and GM guys where I learned some of this:
http://gm-volt.com/forum/index.php - I'm DCFusor there, and will probably post some stuff.
And a little vid on the climate options:
http://www.youtube.com/watch?v=Hs7XChUL ... e=youtu.beNone of which I've yet tried, weather's been nice, so I'm going around in fan-only or windows open. For now, I'm trying to get to full charge off the solar alone, no backup generators or anything. Matter of honor to see if I can.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.