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Gas generator powered ebike with AC motor?

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Gas generator powered ebike with AC motor?

Old 07-30-18, 02:20 PM
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toeofawesome
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Gas generator powered ebike with AC motor?

Where I live there is a restriction on Ebikes to 750 watts or 1 hp. I just so happen to have a 1hp 120v AC motor. Heavy duty rated for continuous use. So in theory can I plug that motor in to a small cheap gasoline generator, and use it to power a bike or trike? Im planning to just skip the whole battery thing, and run it direct. Can anyone see any problems i may have with this setup? I intend to use this for longer distance camping/hunting trips. to haul gear and whatnot.
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Old 07-30-18, 02:46 PM
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Originally Posted by toeofawesome View Post
Where I live there is a restriction on Ebikes to 750 watts or 1 hp.
I would guess there are restrictions on using gasoline engines also, even indirectly.

(please correct me if I'm wrong.)
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Old 07-30-18, 03:47 PM
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Hmmm...

It probably would work.

I'd look for a good 3 phase motor and 3 phase variable frequency drive.

But, the whole gas/electric system seems a bit redundant. One option would be to make it like a hybrid, with the generator charging the battery which runs the motor. Thus you can run the generator at a constant rate, and use a bit more or less power as needs require.

Running it at times in full E-Bike mode would get around complaints that it is a gas bike with a electric coupled transmission.
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Old 07-30-18, 04:08 PM
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+1 with CK, but watch out for the "greenies" who might point out that you are using an inefficient gas engine to charge a battery (probably somewhat inefficiently) to power an electric motor relatively efficiently (85% or so if the data are correct). Please note this analysis is from a Chemist, not a smart person.
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Old 07-30-18, 04:32 PM
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I considered this myself and couldn't see a legal issue. There is no law against carrying a generator. There is no law stating how your e-bike get's it's electricity. The law states the bike must be powered by the electric motor, it must be 250watts, pedal assisted, and restricted to 15.5mph in the UK. The generator is not propelling the vehicle itself.

Generators are quite weighty, given the amps you'll need, and i struggled to find one that'd put out the required wattage for that ampage. If you can find one small and light that'd do 20A at 24v then that'd probably be the best route, as finding 36v is likely to prove trickier.
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Old 07-30-18, 05:14 PM
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Originally Posted by MikeyMK View Post
I considered this myself and couldn't see a legal issue. There is no law against carrying a generator. There is no law stating how your e-bike get's it's electricity. The law states the bike must be powered by the electric motor, it must be 250watts, pedal assisted, and restricted to 15.5mph in the UK. The generator is not propelling the vehicle itself.

Generators are quite weighty, given the amps you'll need, and i struggled to find one that'd put out the required wattage for that ampage. If you can find one small and light that'd do 20A at 24v then that'd probably be the best route, as finding 36v is likely to prove trickier.
I have played around with generators in the past.

I think there are some small 350 to 500W generators. 2 cycle? 4 cycle? They are light and compact.

Of course, 1 HP continuous will require somewhere between 1KW and 1.5 KW. But, intermittent with battery, it should be able to use a bit less.

One issue I ran into with small generators is that their DC output was generally very limited. Maybe 8A, 12V. One had to use 110V (or 220V) to get their full output power. And, thus more power conversion to whatever the battery bank requires.
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Old 07-30-18, 05:53 PM
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Originally Posted by toeofawesome View Post
Where I live there is a restriction on Ebikes to 750 watts or 1 hp. I just so happen to have a 1hp 120v AC motor. Heavy duty rated for continuous use. So in theory can I plug that motor in to a small cheap gasoline generator, and use it to power a bike or trike? Im planning to just skip the whole battery thing, and run it direct. Can anyone see any problems i may have with this setup? I intend to use this for longer distance camping/hunting trips. to haul gear and whatnot.
I read the whole thread, and amazed at the many posters failed to read: " I .... have a 1hp 120V AC motor." So you are looking for a generator system that puts out ~10A @ 120V .; which are very common in the USA.

How do you plan on controlling the output of the motor? What style of AC motor is it? ref: https://en.wikipedia.org/wiki/AC_motor

There are almost as many control types as there are types o AC motor. Some are practical for use in powered vehicles.

Advantages of having batteries:
* you don't need to run the ic engine all the time.
* you can get away with a smaller generator because it is highly unlikely that you will be going flat out all the time (the police would notice you racing along at over 30mph).
* reference: research studies on the optimal size for a hybrid vehicle's battery system.

A BLDC motor (very common for ebike use) is a sort of AC motor, it is fed 3 phase variable frequency AC, usually synchronized by Hall effect sensors. It can just as easily be fed 50/60 Hz three phase and would spin at a constant speed.
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Old 07-31-18, 07:05 PM
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How do you plan on controlling the output of the motor? What style of AC motor is it?

There are almost as many control types as there are types o AC motor. Some are practical for use in powered vehicles.

Advantages of having batteries:
* you don't need to run the ic engine all the time.
* you can get away with a smaller generator because it is highly unlikely that you will be going flat out all the time (the police would notice you racing along at over 30mph).
* reference: research studies on the optimal size for a hybrid vehicle's battery system.

A BLDC motor (very common for ebike use) is a sort of AC motor, it is fed 3 phase variable frequency AC, usually synchronized by Hall effect sensors. It can just as easily be fed 50/60 Hz three phase and would spin at a constant speed.
I have no idea specifically what kind of motor it is. i know its single phase, AC and 120v. Plugs into a wall outlet so i figure it can run on a genny. I plan to gear this very low. 10mph Max. This isn't an in town commuter. its more of a mechanical mule i can legally take places i can't take my moped/scooter, which is my main form of transportation. A Hunting/Camping tool. like an ATV For places ATVS aren't allowed, but bikes are. Hoping to get away with a simple On/Off switch, engaging once i pedal up to speed, like a car transmission. or some kind of dimmer switch.
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Old 08-01-18, 02:03 PM
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Originally Posted by toeofawesome View Post
I have no idea specifically what kind of motor it is. ........
Until you determine this, and then learn how control that type of motor, the project is not going anywhere.

How fast does the motor spin? Is the speed frequency dependent? Many AC motors are rated for just under 3600 rpm (like 3450) at 60 Hz and just under 3000 rpm at 50 Hz. The just under is because they slip to produce torque, the output speed is dependent on the torque taken from the motor, it will try to get to its sync speed (for example 3600 rpm at 60 Hz, but it produces no torque at that speed).

To go ~10 mph, you need to spin the wheel at about 120 rpm; 30:1 gearing is non-trivial. It would be less expensive to purchase a hub motor wheel kit than a 30:1 reduction system that will survive the torque required for meaningful assist on a bike.
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Old 08-02-18, 06:59 AM
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that's really not a suitable motor for speed control. It can be done, but it's not going to be light or cheap. Far better to get a retrofit kit that is made for purpose. I have worked in motor control and have a collection of small brushless motors and I have considered trying to use one of them. But it's just not worth it with the systems I can buy that already have all the engineering done.

I also don't think the power source is the important part of the legal power limit. So just because it's coming from a generator doesn't mean you can cheat on the limit. If I were really worried about it, I would just take the name plate off of it. You probably aren't going to get 1hp out of that motor anyway.
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Old 08-02-18, 02:04 PM
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Not quite the same, but this was recently posted to a popular site which bills itself as "the front page of the internet" (original at: http://www.jankyshack.com/wp-content...801_151622.jpg ):

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Old 08-02-18, 07:23 PM
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Originally Posted by toeofawesome View Post
A Hunting/Camping tool. like an ATV For places ATVS aren't allowed, but bikes are.
If you enter a trail system that posts "no motorized vehicles"...

You might get away with a pure E-Bike.

If someone hears your gas powered bike motoring down the trail, you will get reported to the local forest rangers or local law enforcement.

I'd also be annoyed if I had hiked 10 miles in, and some showed up with a noisy generator (and E-Bike).

Last edited by CliffordK; 08-02-18 at 07:34 PM.
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Old 08-02-18, 07:29 PM
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When I was driving an electric vehicle for a while, I did start thinking about a gas generator as a range extender.

My idea was to just fix up a small trailer with a small gas or diesel generator that generated, say half the power my pickup consumed.

So, say I had a range of about 50 miles. By using the 50% generator, I could likely push that 50 miles to 100 or so pretty easily. There would be less of a chance of getting stuck with a dead battery, and overnight, I could do a full recharge.

If you had a camping E-Bike. Then around town, just use the E-Bike. When you're ready for an overnight trip, grab the trailer and take off. Camp at the trailhead and fully charge. Then head out into the mountains, battery only. On your way out, camp at the trailhead again, recharge, then head home.

A small solar panel may also help.

Might as well also add an auxiliary battery and fuel tank to your range extender trailer.

Last edited by CliffordK; 08-02-18 at 07:32 PM.
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Old 08-07-18, 08:37 AM
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Originally Posted by WillAdams View Post
Not quite the same, but this was recently posted to a popular site which bills itself as "the front page of the internet" (original at: http://www.jankyshack.com/wp-content...801_151622.jpg ):

my eyes are bleeding from the mere sight of that ....thing
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Old 08-07-18, 01:27 PM
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Originally Posted by CliffordK View Post
When I was driving an electric vehicle for a while, I did start thinking about a gas generator as a range extender.

My idea was to just fix up a small trailer with a small gas or diesel generator that generated, say half the power my pickup consumed........
Like this: Mr.Sharkey's Pusher Trailer ?
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Old 08-07-18, 02:04 PM
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Originally Posted by nfmisso View Post
Similar idea.

I think a pusher trailer pushes.

A generator trailer supplies power to the battery/electric motor.

I think pushers are not uncommon for heavy cargo bikes, but I'm not sure I'd want to use one on a lightweight bike.
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Old 08-11-18, 12:46 AM
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Originally Posted by CliffordK View Post
A small solar panel may also help..
It would not. A very large solar panel. Like an entire roof top worth of surface area, now you are talking. If the o.p. wants a range extender, the most practical idea is to use the trailer to carry extra battery capacity. Most generators are not built with mobility in mind so they are unnecessarily heavy. A motor designed for 110V AC is also not going to be a willing participant in the project. It will not have the proper hardpoints to be mounted on the bicycle, or on the trailer for that matter, and it will be twice as heavy as it needs to be. Overweight generator+ overweight motor+ kludgy drive system = failure.
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Old 08-13-18, 07:47 PM
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There is a legally blind gentleman on YouTube with a trike similar to what you would like to do.It is custom built so he can go long distance without the need of a license since it only does the federally allowed speed limit.
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Old 08-17-18, 02:16 AM
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Good chance that is a squirrel cage motor, in which case the start up current will be higher than the running current, so your generator would need to be twice as big as the motor rating would suggest...
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Old 08-22-18, 02:57 AM
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LOL wow!
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Old 08-22-18, 03:07 AM
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Originally Posted by WillAdams View Post
Not quite the same, but this was recently posted to a popular site which bills itself as "the front page of the internet" (original at: http://www.jankyshack.com/wp-content...801_151622.jpg ):

Pffft! This is a great idea! 49cc scooters are way too practical, along with ebikes that qualify.

I've got a small coal burning oven. Where can we fit this in?
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Old 08-22-18, 05:36 AM
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Originally Posted by Bang0Bang00 View Post
Pffft! This is a great idea! 49cc scooters are way too practical, along with ebikes that qualify.

I've got a small coal burning oven. Where can we fit this in?
Number one rule of bicycle design is that every possible bicycle-related invention already exists, regardless of merit. Colin Furze made a jet powered bicycle, and you can find youtubes of a steam powered bicycle made in the last few years.
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Old 08-22-18, 12:14 PM
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Originally Posted by unterhausen View Post
Number one rule of bicycle design is that every possible bicycle-related invention already exists, regardless of merit. Colin Furze made a jet powered bicycle, and you can find youtubes of a steam powered bicycle made in the last few years.
Yeah, but clean coal is the future! The FUTURE! I tells ya!
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Old 08-23-18, 06:50 AM
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I'm reasonably sure the steam bike is powered by coal. Jet is powered by propane, but coal slurry has been used as a jet fuel in the past.
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Old 08-23-18, 01:16 PM
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Lightbulb

On the river shore we have an old electric trolley ,
but without the overhead electric power lines,

it has a motor-generator, car , pulled in one direction ,
pushed in the opposite direction..

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