That's very interesting. I am quite keen on the idea of getting a used i3 in a couple of years. Are yours the Rex version? Do you mind if I ask what range does that give in real world use? And is it feasible to keep topping up the petrol tank on a long journey to keep using the generator in preserve charge mode, or is it just a one-time use?
My i3 is the Rex version with the 94Ah battery. The range extender gives about 90 miles of use on the 2 gallon tank on top of the c135 miles of electric power. I have been known to carry an extra can of petrol in the boot when doing long trips in areas of charging point desert (we have a few of these in the north of the Peak District) but have never actually had to use it.
The range extender will only operate to maintain charge level in the battery - it cannot be used to re-charge, but it can be activated manually (and turned off again) at charge levels below 75% and if you're planning a long trip then it works best to use the Rex whilst on motorway or fast dual carriageway and switch it off when in town or frequently stopping. It works automatically and permanently when the charge level drops to 6% and behaves much like a normal car with stop/start, starting as soon as the car exceeds about 5mph.
It is, however, a very small engine and does not give enough power for long, fast uphill stretches of road - the battery depletes in this situation but will recharge later to its initial charge level. The trick is not to let the battery get too low before using the Rex if you know the route has big demands.
Having said that, most of the time I never use it - fuel consumption over the past year has been about 2 litres (in 9000 miles) BUT it is the get out of jail card when the battery is depleted and with that you're quite able to run the battery to its last few miles of range without worry of becoming stranded.
John
