The same or less than a full petrol car. I think they all warranty the traction battery for 10 yrs these days so none of that "high cost of replacement battery" stuff applies any more. The Prius went for 14 yrs on its original battery and it cost $450 for a replacement from the wreckers. Our plug in range extender battery will probably cost any where up to $10,000, but if it only lasts for 5 yrs rather than the expected 10yrs plus, it still works out to 10 cents per km with the average car travelling 20,000km per yr. The extended range this more expensive aux battery upgrade will cost will give us around 200km range on full electric and over 400km when running in hybrid mode. Fuel usage while in hybrid mode is around 2.5ltrs/100km ... well unless the right foot gets a bit heavy, then it's up around the 5ltr/100kms but I doubt you rive at those speeds anyway
T1 Terry
. Have a friend who has one and is so wrapped in it, they never stop talking about it and how far it goes on a charge. Had a couple of rides and one drive in it and would have one in a flash. Went with her to the EV show here in Tas last year and she tried out a few Ev's, the Kona was the one she jumped up and down about and bought one as soon as she got home. I'd have one if had the money, but can only afford to get my cruiser engine rebuilt at 497000klms when it started using heaps of oil. Not bad for a veggie oil powered car.
It certainly would be the ideal choice and could be adapted to provide virtually limitless house power for the big bus yet recharge from solar either on the big bus when travelling or the shed roof at the block when they make the big move.