The i-MiEV would have to sit for a long time and be parked at near empty. Unlike Tesla vehicles, the i-MiEV completely disconnects the drive battery from the drive inverter and DC converter when the car is turned off. Tesla vehicles, however, keep the battery connected all the time to power telemetrics, BMS and thermal mangement, and (Model S) power the door handles. The Roadster is the worse offender, as a circulation pump runs nearly continuously even if the car is off and unplugged. I'd say that the Roadster is the noisiest EV I've driven with all the pumps running.
They've improved idle power consumption in the Model S numerous times since its release, plus there is a button on the touchscreen to completely power down the car, though it says that should only be used in emergencies or if work is needed to be done on the HV system. Not quite sure on how the car is powered back on :? .
When the i-MiEV is off, the EV-ECU and other ECUs are powered by the 12 volt battery. Only the cell management boards in the battery pack are powered by the cells (I believe, this is how other BMS work) in the main battery. Leaving the i-MiEV sit too long may result in the 12 volt battery going flat (as would nearly any other car). I've left mine for a week without issue, but when my car was at the dealer for a faulty cell, I did start to receive 12 volt low warnings from my OVMS module. Could have been caused by the mechanics accidentally leaving a light on (I suspect my LED lights as the switches were both off when I got it back). That still took 2 weeks before the 12 volt was low.
I'd recommend the small solar panel as you have on your Golf for storing the i-MiEV, though it would need to be tied direct to the battery as the interior accessory outlet only works with the key on. Between the panel and storing the car with half a charge on the main battery, you shouldn't have any worries about several months-long storage.
