Range-extender Sidecar for EV motorcycle

[MazdaMatt]

Novel concept, switching it on and letting the electric kick-start the gas motor, then the gas motor bumping up the electric motor's speed to make it push current the other way. Clever.

[skyl4rk]

I had a set up where an Arduino would sample the system voltage and the intent was to either adjust the gas motor throttle with a servo, and/or to use a relay to switch the gas motor and dc motor off, shutting off the series hybrid range extender. However my weedwhacker motor and low output dc motor never really threatened to overcharge the batteries. If I had a more powerful system, some type of control would have been necessary.

As it was, I just ran the incredibly loud weedwhacker motor with an inadequate muffler at high rpms all the time, which tended to frighten women and children.

Lead acid batteries can take a lot of short term abuse. They only get overcharged when you are stopped. When the throttle is on, the drive motor is dropping the voltage enough so that the batteries are not getting overcharged anymore. It would be nice to have a system that would stop the gas motor when you are coasting or at a stop.

[Thalass]

The Rav 4 Long Ranger trailer is a great example of the series hybrid trailer. I'm using it as a source of ideas for my EV, which I want to turn into a series hybrid eventually.

iirc it was a 500cc motocycle engine driving a generator, and I think it had a few batteries on board too. Not sure how they sent the power to the car, though.

[MazdaMatt]

I'm impressed with the steering mechanism on that trailer. As you back up, it automatically keeps itselve in line with the vehicle so you CAN'T jacknife it. Crazy.

[wolfraven]

I liked the Rav4 trailer...and I was kinda impressed with the amount of effort others have already gone into for extending the range of their EV's... The VW hybrid pushtrailers were pretty cool, but IMHO you're still being pushed...which doesn't work for a motorcycle trailer as well, but others have done that anyway and it seems to be awesome. I happen to have already read quite a bit (like last year or before that) about a few slightly different generator technologies...using microturbines. The ones that started me reading about them aren't due out yet, or very soon...but they're also smaller than what you're after...but there are fairly decently sized microturbines for RC airplanes on the market. I'm still looking for an alternator around that can run at those rpms, because that's where the juice comes from in flight with the airlines! 30,000 rpms is a lot...but hooked up to a reasonable alternator directly would be a LOT of power, and if that doesn't work (seriously, I'm not going to hand-wind that or try to shove one in myself unless it's rated for it, and I'm still looking) it's also possible to use it for a steam generator, in which case whichever "hobbyist" turbine you find with the lowest exhaust temp is probably going to be the best bet...and nobody makes mufflers for turbines that small atm lol! Just my idea.

[Thalass]

One advantage of a steam engine genset would be that, being an external combustion engine, it could run on just about anything, and the flame could be tuned to burn completely - reducing emissions - as long as you could feed the fuel into the fire in a controlled way. Unfortunately piston steam engines aren't much more than 10% efficient, and steam turbines aren't much better.

Stirling engines are also external combustion, but are (theoretically) very efficient. But they also have very low torque, so would need to be run at very high rpm and geared down to useful levels.

[johnrobinson457]

Howdy,
I've been a member of the Steam Automobile Club of America for over 25 years now, and there are very few steam engine vehicles that are new on the roads, for a reason, they are theoretically efficient, but theory and practicality are two different animals. I work at the University of Wisconsin Mechanical Engineering Dept, as a Mechanician for the Heat and Power Laboratory for Senior Undergraduates, and we run both a steam turbine and a gas turbine for teaching. Steam turbines use steam, huge amounts of steam at high pressures, 180 PSI+ steam pressures. Small gas turbines use fuel. Huge amounts of fuel, they turn fuel into noise, and at very high RPM, 80K or more. Both steam and gas turbines just are not practical for moving 500-1000 lbs of vehicle and rider with any efficiency. might as well just drive a Hummer.

[Intrigued]

Yeah, they're not efficient for small jobs, but for pulling a million-pound train up to 60 mph, or pulling a hundred thousand pound airplane up to 400 mph, they're great!

EDIT: Yeah, I know that trains nowadays are for the most part diesel/electric, but there were a lot of steam engines not that many years ago...

[bennelson]

Hey Guys,

Thanks for all your input.

I have been out of town for a few days, and I come back to PAGES of new comments on this thread!

I was on a road-trip with a few Citicar buddies. The one guy, Rich, has a Generac generator which he got for free because the inverter on it is busted. It's a very compact 3K brushless dc generator. It also runs off propane. (Which is about as clean of a fossil fuel as one can burn)

I think we are going to track down some tech information on this generator, and see if we can find what the output DC voltage is on it. Then I would only need to figure out how to convert that to say 56 volts or so for charging a DC system, and control the amperage.

On the drive home from the Citicar gathering, I saw a great motorcycle with both a sidecar AND towing a teardrop trailer!
You can't see the sidecar too well, as we were on the wrong side, but I made sure to give the guy a big thumbs up as we passed him.

A smaller version of his teardrop trailer would be perfect for a small generator setup!

[Intrigued]

Boy, that looks about the right size to me... for a generator and about 4 barbecue bottles of propane...