After I first got my iMiEV it took me about a month to get the TED 5000 energy monitor up and working properly (had to return one of its modules). Since early March I've been meticulously recording the amount of energy drawn by my iMiEV, whether at home or at a public charging station (and I no longer opportunity-charge at friends' homes with the iMiEV).
Every once in a while I charge to 100% and I then add up all the intermediate charge amounts since the last 100% and figure out what the miles/kWh, kWh/mile, and kWh/100miles were for that interval. This is the actual wall-to-wheels energy consumption, but note the tire pressure caveat at the end of this discussion.
Happy to report the following summary of our everyday normal driving energy consumption for 2 March through 13 May. If you're a purist, you can round off appropriately and recognize that the TED monitor is a consumer product (but it was within 1% of my Kill-A-Watt), and the mileage is off the iMiEV's odometer (which is also within about 1% of the GPS):
Miles driven: 1937.3
Energy consumed: 442.813kWh
Which is significantly better than the 30kWh/100mi (27 City, 34 Highway) EPA Monroney sticker.
Using the EPA's conversion of 33.7kWh/gallon, this would yield 147.4MPGe. Not too shabby, even if I disagree with their metrics.
Now, with this information, if you know how much you're paying for electricity in cents/kWh and if you know how much you drive per month or year, you can quickly figure out what your monthly or yearly costs are.
For example, if I didn't have solar and had to pay the going rate for my off-peak (PG&E E-7) of $0.08/kWh, this would yield 0.08*0.2286 = 1.8 cents/mile! If we compare this to a subcompact that gets 30mpg, with gas costing $4.50/gal around here nowadays, that subcompact's fuel costs would be 4.50/30 = 15 cents/mile. Fair to say that our iMiEV's "fuel" cost is an order of magnitude less than an average US vehicle.
Some more tidbits from my data-taking:
Best Range Remaining (RR) after top-up: 98 miles
Worst RR after top-up: 57 miles
Best energy use recorded: 5.32miles/kWh (18.8kWh/100mi) over 113.2 miles
Worst energy use recorded: 3.64miles/kWh (27.5kWh/100mi) over 87.5 miles
The EPA says that the iMiEV's all-round range is 62 miles. By comparison, if I arbitrarily say that our 16kWh battery has an effective usable non-stressing capacity of, say, 14kWh, this would mean for us this averages out to a non-stressing range of 14*4.375 = 61.3 miles ... I just calculated this and, frankly, am surprised that it's so close to the EPA number. In case you're interested, full capacity would be 16kWh*4.375mi/kWhr=70miles.
These numbers come from a combination of my wife's driving (she's a featherfoot) and my own, which ranges from unabashed leadfoot to hypermiling depending on how far I'm going on any particular trip. Average springtime temperature probably around 65degF and altitudes ranging from sea-level up to 2000'. I would guess an overall 50/50 mix of city/highway - sorry I'm not more accurate, as this is the major consumption determining factor. The only "modification" to the car is that I'm running the tires at 55psi, as I perceive that this not only improves mileage but handling as well (I run high tire pressures in all my cars).
Hopefully this puts some mileage speculation to bed. If anybody wants, I can publish the summary spreadsheet as well. I'll occasionally update this as I'm still diligently recording the consumption.
Finally, as they say, YMMV.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV