Sounds like the Volt is working out very well for your situation. Yes it can feel funy sucking away at your house bank to fill your car. Even I feel funny about it at first (though I don't do it often) and I have lithium's that are not to fussed about SOC. As long as you know your house banks SOC and keep track of the load so you can keep it within a manageable scope that's within spec of the bank then you should feel to guilty.
My big concern with a BEV / hybrid is baking the traction pack. Heat is a evil thing for lithium cells. We can baby our Imive as it gets charged in the cool insulated room at about 25c even in summer. We drive it and then if its parked its parked its always parked in cool shaded places.
Out ute gets absolutely baked taken around Australia some places must be close to 50C and it's unavoidable where you park it and for how long some times. You return to your car with your thongs stuck to the melted road , leave it at the beach carpark all day frying in the midday sun.
I'm just thinking of the outlander that basically has a slightly smaller imiev battery with the same cell slung under it in a box. On a drive from say Brisbane to Adelaide over summer. How would that traction pack be feeling after humming along on the freeway for the past 10hrs with all the heat from the 2lt petrol motor, exhaust blowing onto it and the 1000s of miles of black top you have just covered radiating heat up onto the traction pack. Cars realy are a terrible place to house a battery in a climate like AU.
I think I would just feel so guilty of how abusive I was being to the battery.....some times ignorance is bliss. I think I need one car I can absolutely abuse and have little concern for....sorry Isuzu
On the subject of saving money or cars paying for them self. You really have to do a hell of a lot of km to make that come true. Just the registration and insurance cost on a 2nd car is about $1000 + a good $200 or so for diy maintenance and tiers. If you only travel say 300km a week 15,000km PA in a reasonably efficient small car 5lt/100km at $1.30lt is $975 of potential savings to be had.
So the most you can save is about $1000 on fuel and say $200 in maintenance (assuming your EV electricity is free) having to spend $25 - $30k to do that as a 2nd car isn't going to work as even the banks will give you 3.3% pa on that lump sum or $1000 pa on 30k. Though if your doing 50 -60,000km pa then it can start to work.
Though driving in silence and the overall driving experience and self insurance of a off grid EV is worth a lot of money
Offgrid 2008, Selectronic PS1 6kw/48v inverter, x 2 Midnite solar classic 150 MPPT, 3960w NE PV 24 x 165w BP panels, 4200w NW PV 21 x 200w DAQO PV, 16x400ah lithium.