Who is ready for the next level?

Sidewinder Jerry

Sidewinder Jerry

Well-Known Member
Putting a challenge to out there to all builders. Gas electric hybred bike. Imagine 300 mpg. I thinking alternator to recharge batteries while gas is running.
 
After making a bike which shifts gears automatically by means of the throttle; I wondered what else could challenge me. Now I'm thinking gas electric hybred bike. Imagine 300 mpg. I'm thinking some type of alternator to recharge batteries while using gas.

The challenge is who of you out there has the skills to build such a bike?
 
Re: hiya, newbie with a Dyno Glider

The point of a hybrid is that IC engines fall on their faces, so to speak, when dealing with overcoming inertia. Spooling up consumes crazy amounts of fuel. Electric, on the other hand, has crazy torque and minimal loss to spooling, heat being the problem with elecs, but in hybrids they're utilized almost solely for the torque.

So, in a sense, our bikes are hybrids, but instead of a ridiculous amount of super earth friendly heavy metal batteries and electric high torque short burst motors, we have feet. That's why we get 150mpg.

Unless you run from a dead stop by revving and dumping the clutch...but if you do that, please stop :)
 
Last edited:
Recharging the batteries while using gas will just reduce your gas mileage. You're putting energy in to inefficiently get energy into a battery. You'd be surprised how much an alternator in your car drags against your engine. To get the better gas mileage like you are thinking of, you need a regenerative braking system and a better engineered engine.

The braking is very important. Basically you can use the electric motor that drives the wheel to be put in reverse. A generator and a motor are the same thing. Give it power one way and it will spin. Give it another and it will create electrical energy

A 1600cc VW engine gets 20-35 mpg. It has about 50-70hp. The 1800cc engine in the 2000 celica has 180hp yet I've gotten 34mpg with it. Because of the fine engineering these days (as much as people like to complain about over-complicated engines) we can create much more power for the same amount of gas. Moral of the story is that if an engine like the china girl recieved a lot of attention with overhead cams, valves, and other things then it could get well over 150mpg even without going through the hybrid route.

Anyway, just my thoughts.
 
Last edited:
Thanks for the challenge, Jerry!

I like to spar. :-)

Unfortunately, I won't be able to pick up the gauntlet, because I'm just not up to hybrids, yet.

My goal is cheapest possible personal transport. gifted, salvaged, craigslist, imported... no matter... CHEEP! is what counts.
people need to get to distant places inexpensively to keep beans on the table.

But I'll watch to see how your hybrid challenge progresses!

Best
rc
 
I've done electrical work for 30 years before heart problems forced me to retire. I've never did milwright work all I did was install systems to power and control motors. I do have a degree in electronics as well. Still using electric motors on bicycles would be new to me.

Right now I'm researching what is out there. The first thing I'm learning is weight reduction and increased power equals greater expense with the kits, well beyond what I can afford. Another thing I'm looking into is quick charging systems like many of the cordless tools use. What my attempt would be is to build a analog manual system. If such a bike is built reaching around 300 mpg I feel it will get a lot of peoples attention. Then people smarter than me can build a digital automated system like the cars have.
 
I have a tendancy to oversimplify these projects, Jerry. I would add a 24 volt hub motor to the front of a China girl powered bike. The hub motor would be used only during acceleration and batteries are recharged at home. Fuel economy would increase because the China girl would run at lower throttle settings during electric assist.
 
ive seen this...on you tube.. a guy took an electric bicycle. attached a generator. conected it to a marine transformer to convert it to 12 v and put that to a car battery i believe...maybe 9 v...but from there it went to the electric motor..basically made his electric motor able to do longer trips without having to stop and plug it in to recharge....he was claiming a way better mpg than us.. =)
 
Oh that wouldn't cause drag if it was designed to work as a brake. What the issue is, is that to get 10% of the energy you use per "tank" of electricity you would need to stop every 3 city blocks. This all vary's from the speed your braking at, and weight.

http://www.ecospeed.com/regenbraking.pdf

As for the quick charge system, I'm not sure about it. It tends to kill batteries when you shove more amps into them faster than what it should normally handle. Works more for power tools because they aren't used regularly like a commuting bike would. I could be wrong though.


If you ask me, the easiest way to get 300mpg is to be aerodynamic. But that's not really the goal of the thread so maybe a combination of home charging and the gas engine is the best.
 
Issues to consider:

Weight and Room.
Adding an electric motor and battery along with a 48/66cc motor kit would reduce the efficiency of both.
Trying to add yet another part (gen) it would be a big heavy crowded bike even if you could get it all to fit.
Now towing a trailer with a solar panel and charger to charge the battery when it's in sunlight might be feasible though and far less taxing on both motors.

More miles per $ vs Performance.
Seems to me the only way you can make both motors perform at peak efficiency would be to always be using both motors at the same time, even then you have the same weight and room problem but if you want a new challenge then there you have it, design an automatic electric motor controller that senses gas motor RPM and matches the electric to it ;-}

As for a bike generator to charge a big electric motors Lithium Ion battery pack forget it unless you plan to use some 11HP Morini type motor because trying propel you and all the weight AND a generator power draw you'd drop even high performance 66cc 3HP 2-stroke to its knees and you can't charge a LithIon battery while it's in use anyway.

Just my off-hand thoughts.
 
One thought has come to my mind and that's either using the motor as generator while using the engine to recharge the batteries. You may have to run it through a small stepup transformer to do it. The other thing would be to use an ac motor but you would have to be able to adjust frequency to control the speed. I plan to look at how hybred cars are setup to understand what might work on a bike.
 
You must log in or register to reply here.
Back
Top