diy hybrids have been brought up from time to time. The common counterpoints are that it would be difficult to engineer the switch between the two, prevent over-revving of the electric motor, and managing the weight. Typically hybrids have anemic ICE engines to make room for batteries, motors, etc, but you couldn't realistically do that in a regular car without replacing the engine too, and at that point it's just too much work and cost. Also, engineering the conenction point between the electric motor and the drive system would be difficult as well.
More power to you if you decide to tackle it, but it's a lot of work. It might be just as efficient to try and do weight reduction and tuning on the original ICE than hybrid-izing it.
Yes if you have enough money and those willing to help you build it. By yourself, doubtful. But it is possible and every one and their brother will say it can't be done or how difficult it will be. Well no one said it would be easy. It's well within the realm of possible. Practical, not at this time. Some day it may. Most hear would agree just go with straight electric.
In that case it is possible, just like all 'vapour builds' anything is possible.
All you need is imagination, plenty of old envelopes to draw on the back of and a bit of encouragement from the guys here.
At least you know it won't cost you anything.
Only thing that intrigues me (serious question), why 7kW motors in particular? Given you are not going to build it you could have a whole herd of Agni motors linked together. It would be lighter then a brace of Warp9s.
There are some 10kw motors (>20kw peak) used by electric aero enthusiast. These motors are available as DIY projects for the (more) serious DIY-guys. Hook 2 of them to a small(ish) bike engine and we can start talking series hybrids. Leave parallel hybrids to the big auto-makers - they deserve the headaches.
With a serial hybrid you only need to cover your average power consumption for the distance and speed you want to do, and you should be able to regulate it via your on-board charger, making life easier.
serial hybrids & trailer systems are the simplest answer to extending the range of an EV. sadly, it looks like you can't get much better MPG than a prius though.
i kind of think that hybrid cars are a joke though as my 1992 daihatsu charade got 42 mpg without batteries! that's the same as a couple hybrids with about 17 years worth of technological advances. a 40mpg hybrid is a rolling contradiction.
Most generator engines are pretty unsophisticated compared to modern auto engines ( both gas and diesel ). I think that is part of the problem - they use more fuel than necessary because the design is 40 years out of date. A nice small bike engine of suitable power, coupled to modern BLDC motor and drive in regen mode, and stripped of everything unnecessary would make a good starting point weight wise.
Another good option would be something like a 1 litre 3 cylinder turbo-diesel driving a reasonable (25kw+) generator, on a trailer. That should give good economy, but towing a trailer has its own penalties, so you would not see all the gains from the more economical engine.
My personal opinion is that if you run a small BEV, buy a normal car for longer distances. If you can afford to convert a larger vehicle or a small truck, you might have some space for a generator. It would then be a space/weight trade-off between required minimum range, battery weight, generator weight and power and your budget. I think this is a difficult balancing act, and most is liable to get it wrong.
I think that the definitive comment so far has been from the Daihatsu owner.In my L series Subaru went to fwd electric similar to Larry Reiss, but returning setup to ice fwdwith elec direct to diff. Reason? long distance travel required & I do not want to tow a trailer.Grand plan is to leave ice idling to give supplementary charging when required whilst using elec.The Daihatsu owner's comment also stated the obvious that with new gen diesels giving as much as 70mpg (top gear story) electric has to be radically improved in the distance aspect.
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