|The BMW i3 range extender engine which is made by Taiwanese manufacturer Kymco for BMW.|
The range extender engine will be a 650cc Kymco engine borrowed from the BMW C650 GT scooter. It will be highly optimized to lower noise & vibration and will only put out 35hp, compared to its 65hp when used for the scooter. The gas tank will be a miniscule 2.8 gallons and BMW has stated it will extend the range of the car about another 90 miles, effectively doubling the cars range. However many journalists are wondering will that added 90 miles be an ultimate driving experience or the ultimate disappointment?
|The REx will fit nicely next to the e-motor|
I'm not exactly sure what "not intended for daily use" means though. That sounds like you'll break if you use it every day and that's obviously not going to be the case. Will the cars performance be so inhibited while in REx mode you wouldn't want to drive it that way every day? I find it difficult to believe BMW would add the range extender if it was so weak it offered terrible performance while in use. Willisch must have confidence it will perform admirably in REx mode though because he predicted at least 80% of US i3 buyers will order it with the range extender. I've also heard it described by some as a "limp home mode" by some(not BMW people) and I also don't believe that is accurate either.
My guess is it will be pretty much in between the hobbled horse and "ultimate driving EV" when the range extender is in use. I think it will drive fine on flat terrain, and can probably even drive along at 70mph in those circumstances. However introduce an extended incline or times when you need to go 75 or more to keep up with traffic and the car could quickly find itself gasping for enough energy to maintain its motion. It definitely won't be a "It'll get you home but you'll have to crawl along at 30mph" but lets just say you'd lose if you try to autocross in REx mode. Then again, if BMW does reserve a fair amount of the battery back as a buffer, it could perform very well for the first 20 miles or so, before the stored energy gets to a minimum and the REx is working at maximum output to sustain the charge level.
The bottom line is if you really just want the security of knowing you'll never have to call a tow truck to get home, then the REx will be worth its weight in gold for you. I've been there on the side of the road a couple times in the past four years falling short of my destination so I know it will be a valuable asset for those circumstances. However if you plan to use the range extender to drive hundreds of highway miles to make a far off destination, then I'm guessing this isn't the right EV for you. Horses for courses. Hopefully, we'll get the answers to these questions and all the technical specifications of the i3 soon. It launches in Europe in the fall so the wait is nearly over.