The Gas/alternator powered E-bike

I have been intensively working on this since September. The bike is a Mongoose FS with the rear suspension tied down (wound the rear spring to limit travel and KEEP the motor drive chain on).
Using a 250 watt scooter motor,chain and sprocket to a jackshaft made out of a freewheel mx rear hub. From there, a bike sprocket welded on the other side of the jackshaft, driving a 42 tooth bike (standard?) chain ring adapted to a China girl rag joint.
Works OK, around 14 to one sprocket ratios and 13 mph speed with 24v batterys feeding it.

The following is WITHOUT the 24volt battery pack and instead uses an engine driving an alternator w/ a small 12v feeding the field circiut.

The alternator I am using is a Ford, external regulator style (NOT using the reg. at all). It has the power output directly connected to the scooter motor wires, with only a switch on the handlebar to shut it off and on.
Scooter motor speed is controlled by throttle position of the gas engine and the on/off switch. Later I will add a 2nd switch to the throttle control to kill big power at idle.
I am using a 12volt batt. to put current into the field circuit. Later, I want to add a snowmobile regulator (try to anyway) and a diode to charge the battery off the big output of the alt during use.

One of the tests I did was to remove the alternator and drive a 450w scooter motor as a generator. This did NOT work, the bike did move at a snail's pace, yes, it did generate current, but not much.

2weedwacker motors were tried. In a geared- down mode, one labored to just spin the alt. (probably a tired engine). The other, labored to spin both alt and drive motor with out load in direct drive - bike laying down- not ridden.

Here is what worked but the engine is too heavy for the rack mount- the HF 79cc is a sweetheart engine. With one to one ratio, spinning the alternator, I registered 50 volts at full engine rpm (3600).
This was enough to launch the bike with just a bit less inital thrust, than when it ran off batterys (not having the big reserve of amps), but still acceptably quick, and once getting up to speed, had to dial back to near idle to keep from overspeeding the scooter motor and maintain level speed (around 13-15 mph).

Having seen the alternator powering the bike, I swapped engines. To a 50cc Tehumseh snowthrower engine.(looking for light wt.)
This was a slug, it barely propelled the bike off idle and took forever at ful lthrottle to get up to speed. It is rated at 3 hp - maybe wound tight? But no torque.
The HF was a big block with a blower compared to the 50cc.

Winter is bearing down on the E-bike project. We have had an exceptionally warm November, allowing me to get farther than normal on this project.

I plan on pulling the 6 hp Techumseh off the 24 inch red bike and put it on the back of the Mongoose. Even with that 10 pound engine, the bike will weigh over 85 pounds, BUT total wt. won't be excessive because I weigh 135#. I think the 6hp will have enough torque to replicate the performance of the HF engine and it is ten pounds lighter.

I am out to ride with the same speeds and mode as a normal bike. I just don't want to deal with batterys and controllers. A Milk crate will cover the engine on the rack.
I will be New York legal (with this bike at least).
Hope the info is useful.

Is the 6 horse the 98cc Tecumseh?

Yes, it is off a Toro S-200 snowblower.
Had to put a idle stop tab on the carb throttle lever to be able to use it in a normal fashion. (and not the revved-up single speed the blower had). Real well- made old engine.

professor do you have some photos? of your project wold be cool to see it. thanks!!
Norman

Professor, it's Denny "from the OTHER site". I was a little confused about your tecumsehs. You list the 49 as 3.5 hp and the 98 as 6. Wondering where you got those numbers. My 49 is rated as 2 and the 98 is 3.5. Might explain the bogging under power.

Have to agree, the 98cc is a pretty nice old dependabe engine.

smiley was the best I could do. :>)

Norm- I clicked on the wrong message that came up on my other computer. It was a trojan? and killed it's usefulness for now. So I'm on my wife's little notebook and I can't figure out HOW to get the pics from it into Photobucket! The thing uses Linex, not windows. When I get back to work I can do it.

Denny- great to see you here! That handle is a doozie.

Anyway, I know the big one is 6 hp because that is what Toro rated it (right on the designation of one of the blowers (and it ACTS like it has that much power -both on the blower and on that bike I did).
The little one, I grabbed 3 hp because I think I found it on the web. And it is 1/2 of the big one.
I just bought another Toro for $50-a 620 as a motor back-up. Nice unit, works great, but these are not too good in Buffalo- mankillers when you get a lot of snow. Driving them into hard-pack. Can't stahl them though- they really got 6 hp.

Hmmm, I will say that mine are pretty snarly in a two stroke sort of way too. Just went by vendors ratings. Of course that was governed to 4400 rpm if I remember right.

Handle is wood butcher with no vowels.....wood butcher as in carpenter/construction. :>) I've used that on some building sites. Self explanatory to people who know, and mysterious to those who don't. :>)

E-bike motor is a 450 Watt?

This particular bike is home made and using a little scooter motor of 250watts. E-bikes use a variety of outputs. Currie uses 450w motors, I think. The 250 seems fine to me, but is geared down, geared up to go 15-20 mph would NEED a 450 watt motor.

Here are a couple of pics of the drive motor set-up-



It looks a bit busy with 3 idlers, but two of them keep the chain off the frame.

The motor can be replaced with a 450w later on since it is the same diameter, just longer and the mount / clamp lets the motor be slid into position for chain algnment before being clamped down.

The entire bracket that holds the motor and jackshaft unbolts, leaving that part of the frame unmolested except for the raised shock mount hole.
The back triangle has a couple of tabs welded to it for the idlers. Otherwise, the frame is stock and can be stripped of everything and be a normal bike again.
Since this is going well, "normal" likely will not happen.

Hey, that's pretty slick. Another goose is getting motorized. I have one with a GX 100 clone in rack drive mode. Has 8-9000 miles on it. Tough frame....seems to go forever. I was impressed with how you mounted the motor in frame. I like the full suspension with all the rough roads I deal with here. Also the frame is aluminum but massive. Light but strong. My next idea is to build an extended rear suspension with an in frame 49cc Honda clone and Nu /vinci hub. Idea is to keep the suspension, and keep the weight lower. It will kind of look like the "extracycle" so I can put some bags over the engine for a little *stealth*. The current set up is bullet proof as far as durability, but has trouble climbing some of the steeper hills pulling a trailer, so hopefully the Nu Vinci will help with that.

Your bike kind of follows my original idea for an electric *transmission" When I finish the Nu Vinci rig, I plan on getting back to the electric, so I will be interested in your developments. You are running into the same thing I found...efficiency losses...I think. Takes a big engine to overcome all that to get useful power to the ground. The upside is simplicity....less gearboxes, chains and jackshafts to wear out and get in the way.

Carry on and keep us posted.

Don't know if I mentioned it here, but I tried to utilize the full sus. and had to tie it down a lot to keep the chain on. It now rides like my hard tail with a sus. seat post.
I thought, that having the drive sprocket from the jackshaft fairly in line with the pivot point in the frame. that it would be OK. Not so!
It takes an amazingly small amount of suspension travel to deflect the chain a lot. Thereby loosening it.
I do really like the Mongoose, but I would recommend a hard tail and sus. seat post and a nice cushy seat.
You know, with an extended rear triangle, the electric drive motor could be mounted behind the frame seat post.

Let me see if I have this right. You have built a bike that uses a gas engine to drive a Ford alternator that powers an electric motor incorporating a battery storage system as well? Brvnkaerv

Not quite. The battery is not being charged as of right now, Remember the battery is only for juicing the field circuit.
My plan is to charge the battery by tapping off the power going to the drive motor (the field only takes a couple of amps) using a snowmobile universal regulator and a diode.

I am anticipating this system could be replicated by people (like me) who are legally limited to an E-bike.
The law in NY (legalizing E-bikes) did not specify that I must have a battery powering the bike. So, not wanting battery power and electronic gizmos which I do not understand- I am powering it with something I DO understand and without the limitations of battery range.
However- the bike is heavy! I can deal with that.

ya know what kills me is I have seen many disabled people in their electric wheelchairs which IMO is the only reason they allow e-bikes (they is to scared to go against ADA to outlaw e-power)

I am the only one I have ever seen ride one of these MB

What about pulling a trailer--put in it a gas powered generator --run the cords to an -e-bike set up--that way you're green but 200 mile range LOL!

Robin you are absolutely right. but you have to correlate the drive motor voltage and type to the generator.
Meaning, if your E-bike is 24 volts like the one I have, you need to feed it with 24v. Generators typically have 110v and 12v outputs.
Now if you make your e-bike powered with a 110 brush style motor (lawn mower, leaf blower, snow blower) - then the normal generator would work.
You have to make sure you don't electrocute yourself! 24v would zap you but 110 can kill you.
I could go with a trailer myself, but where I ride, a trailer is not practical.

are u trying to make what boats call "diesel electric" to get better mileage?

Actually NY state saids its ilegal to even put a gas motor on a bike not just having one run the bike. But if you get pulled over and your bike is powered by a elctric motor and the gas one is just a generator, theres a good chance they will let you go.
But i usually dont see any cops or they dont see me and i never got pulled over yet.
I would go with a electric and gas but i dont have the funds for it and i sold my electric bike stuff,looks like for now i will stick with just a gas bike.

It would be nice to be legal and not look over my shoulder all the time and having to go out of my way and take back roads.

Lil, no, I am avoiding the whole battery deal except for the one that juices the field circuit.
Am working on some kind of regulator to tap the big power for charging it. I am going to see the electrical guys at work to see if they have any ideas.
Picked up two 7812 regulators from radio shack but they can't take any more than 35 volts input.
The bike is done except for that (as far as i know). Haven't run it down the road yet with the 6 hp engine. Made an aircleaner and snorkel tubes to quiet that end and did the same on the exhaust. Silence is golden

Cabin- I found and posted here, the rules they laid down for the e-bike and there was no mention of the power source for the e-motor in the legislation. Who would ever think of such a thing as sourcing the zap to run one from a gen set?
They didn't either.
Today, I almost ordered an HT kit. Ran into two glitches trying to order, so I took that as a sign to back off. Then was watching youtube vids of the HTs and I think they are probably too noisy for me. Fascinating contraptions though, really.

I do plan on doing one more (gas /friction) bike and probably another hybred ( in frame gas generator/ friction drive electric). The Mongoose has gotten real porkey at 92# so far, need to fab up a hd side stand and put in a bullet proof rear tire.

I would NOT recommend doing what I did (lots of fab / lots of time / lots of experiments) to anyone. It was both a challenge and tinker time, so I don't mind.

I have taken 2 rides on battery power and I am able to keep up a pace that normally would be a bit of work to maintain- especially against the wind.

No blazing speed needed for me. Probably with the 450 watt motor I just put on - 15-18mph max- don't know yet.