Bicycle Motor, etc.

[NickCoons]

As a way of becoming less dependent on other people processing fuels for my transportation, I'm looking at taking a standard mountain bike and converting it into an electric bike (which could be recharged in any number of ways).

First, I'm going to find a used mountain bike locally (wouldn't want to trash a brand new one if this doesn't work).  Next, I will need to find a DC motor capable of propelling this bike with me on it.  I'm looking to accomplish a top speed of at least 30mph.

I'd like to leave all of the existing pedals and gears intact.  This will allow me to assist the motor in starting up the bike, and also allow me to continue to use the bike in case the battery dies.. so I don't get stranded.  Or, to even be able to easily remove most of assembly (battery and motor) within a minute or so in case I wanted to use it as an ordinary bike.

I've found a couple resources online, very few, that give not so great details on doing something similar to this (most recommend removing all of the pedals and gears and going completed motor-driven).  Other places sell these types of bikes, but don't have very good pictures so I can't get any details on how they're assembled.

Possible places to mount the motor include underneath the seat nearer the front with the chain and gears on the left side (the pedal gears are on the right), though I could picture this getting in the way of my feet, or possibly entangling my pants.  Or, I could mount the behind the seat to the back and have the chain moving downward, but this would require a very strong assembly to prevent the motor from moving around.  I think the former, with a chain guard, would probably be the best bet, and the batteries could be mounted behind.

So I'd need a DC motor, somewhere around 24V, 1HP, 3000rpms; but I'm open to suggestions on those specs.  But I would want something "short" so it doesn't get in the way of pedalling.  For batteries, I could use two 12V batteries mounted behind the seat underneath a basket of some sort that I could use to carry other items.

Also, I've read that regenerative braking (using your coasting power to recharge the batteries) is not efficient.  I could see how if you were intentionally coasting that you wouldn't want to lose your momentum to charge the battery.. but if you wanted to stop anyway, why would using that momentum to recharge the battery (even if the charge that you get is small) be worse than using standard brakes that grip the wheels?  Of course, I wouldn't know how to "wire" this using the single motor.

So what I'm looking for here is any insight from anyone that might have some input on this (what kind of motor to use, batteries, how to get the best range, best top speed, etc).

[tecker]

   The hub motors that are out there ar good for many reasons . Use care not to put the motor where the chain is a hazard. Gell or sealed lead acid bats are not good for the long run but a good start .I'ts a fun project and a great trip machine .

[Volvo farmer]

I have a 24V motor out of an electric scooter you could have for cheap. It already has a little sprocket on it for a chain. It's not very big, maybe 4" dia x 4" long. I've got no idea of the HP rating or speed though. I've got the scooter's back tire and rim with the big sprocket too if your interested. The tire is only 12".

I have an old Peuegot mt bike you can have too, though shipping would be quite expensive and I don't have a box for it. I'm in Southwest CO.

[Kemper73]

Well,,

after a small search for these motors,,, here is a manufacturer,,,

http://www.greenspeed.us/electric_mountain_bike.htm

They are kinda expensive,, but I do like the motor idea. you would think that we could make a flate plate motor, similar to the axial flux generator, the biggest problem is figuring out the electronics, we would need a laptop on board to controll the damn thing.

Jeff

[Muffloj]

  I have been looking at www.goldenmotor.com for a project i have been working on. They have some realy neat hub ,pancake motors.

  Dont have any experience with the company though.

  If you try them let us know about the results.

 

[finnsawyer]

During the energy crisis when I was an assistant professor of EE, another fellow and I built a battery powered motorcycle.  I did the instrumentation and he did the mechanical.  The thing was not exactly hell on wheels.  It's hard to get range and speed using batteries.  Unfortunately I don't remember the details of its performance.  So, a couple of observations.  If you're going to keep the means of peddling, you need a way to disconnect the motor.  Otherwise you might be trying to charge the battery.  Secondly one horsepower (746 watts or 550 lb-ft/sec) at 30 mph gets a equivalent force of 12.5 lbs.  Is this enough to overcome wind resistance, mechanical losses, and electrical losses?  Probably not.  Another fellow (I couldn't find his posting) was trying for 15 mph which has 1/4 the wind resistance.  So, don't expect too much from your effort.  It'll work, but maybe not as well as you hope.  Good luck!

[Roamer195]

You could think about building an aerodynamic shell to go over the whole bike in order to reduce wind drag.

[hiker]

i tried a gas to elect. conversion on a old moped.

used a 300 watt 12v motor--tops out at 10 mph..

used the same drive setup that came with it..

not very effiant--needs some kind of votage control..

just waiting on some new points to put the gas motor back on...

[nobicus]

One of the best ideas I have seen is to have the motor and batteries in a small two wheel trailer that pushes the bike.  When you want to get fit just unhitch the trailer and when, like me, you feel a bit idle hitch the trailer up with full batteries.

If you do have a good idea about the motor do let us all know.  I was going to have a go at one next spring and try either a windscreen wiper motor or even a starter motor.  You can find some good info about changing these and charging them on the "fighting robots" type sites.  Do a google search.

[whatsnext]

I'd be very interested in getting one of these sets. Have you looked into freight charges? This is a bit off topic but I've been riding a Chinese copy of a Honda Passport for a couple of months now. 113mpg average so far so I'm torn as to practicality of an electric bike.

John........

[Ungrounded Lightning Rod]

Secondly one horsepower (746 watts or 550 lb-ft/sec) at 30 mph gets a equivalent force of 12.5 lbs.  Is this enough to overcome wind resistance, mechanical losses, and electrical losses?

More to the point, if you plus the bike weigh 250 lbs you're not going to get any 30 mph up a 5% or steeper grade, even in a vacuum.  B-)  And batteries are heavy, so unless you're a beanpole and the bike is a lightweight you'll probably total something more with a non-trivial battery.

One horse with perfect efficiency would pull 60% of the charge (the most you ever want to pull) from an 85 amphour battery in a bit over an hour.

IMHO battery-electric bikes using current-tech batteries are fine for level cruising but not so great for hills/mountains.  The hills eat your charge, you don't get all THAT much back coming down, and once the charge is gone you have to lift you, a motor, and a battery full of lead over the next hill, using just your effort on the pedals.

If you decide to try it, DON'T use a magnesium frame bike!  Get a bad short and you might find yourself riding a giant welding torch that can't be extinguished.

[commanda]

For a comparison, have a look at http://oatleyelectronics.com

They have a battery/electric bike.

It's on the front page, can't miss it.

# Speed: 20km/h.

# Motor: 200W

# Battery capacity: 12AH, 24V

# Battery charger: 240V

# Charging period: 4-5 hours

# Range: 15km

# Frame: painted steel

# Weight: 21kg

# Maximum load: 100kg

# Size: 1130 x 390 x 1000mm

So I would use these specs as a guide for what is achievable.

Amanda

[nothing to lose]

 I've been to an old car museum that has like a 1903 (or something) car. It looks like a little coaster cart, Downhill go cart only. It has a 1 wheel trailer behind it that has a 1cyl gas motor mounted to drive that wheel. Really neat little thing.

Anyway if it works for the little one seat car, why not a little trailer like that for the bike. Also lattely I been seeing many LITTLE motorcycle looking minibikes that use a 2 cycle chainsaw type motor. I know someone that has one and seems to get about 30mph from it.

Now thinking on this a little, I think a 2 wheel trailer with batteries and electric motor for electric power, plus a gas chainsaw motor to drive it also, and your pedals for normal power, all 3 combined would be neat and work out really well.

On the flats you could pedal as you want or use electric. For hills you could engage the chainsaw motor to pull the heavy wieght of the batteries and such. In a bind when really tired and out of battery power you could use the chainsaw engine. That little engine might add about 50lbs including a quart of feul?

Durring downhill rides I would try to use regenerative braking. Here where I am I have far to many hills to ride a bike in town and back, either normal pedals or batteries won't cut it for me on these larger hills. I been thinking on a Gas, Electric, pedal hybrid myself. On my hilly route I would have long streches DOWNHILL where I will need brakes or I would just go way to fast to handle the road.

Also when people talk of carrying the extra weight up hill and using up battieries, I have gave that some thought. In my case here I need brakes down half the hills or more to not go too fast, but then I go right back to another uphill. So if using the road to your advantage, regenrate your power comming down half the first hill, then freewheel down the second half (your going pretty darned fast) as you start up the next hill wait till you start losing speed then hit the power. When I rode a bike across this route before using only pedal power, the first hill is a baer to go up, always need brakes down the first half of the hills, and gaining more speed down the second half than I realy want I then only need to pedal up about a 1/4 of the next hill, though I am starting to go a bit slower than I want at the top but of course I am about to come back down again and need brakes all over. 90% of about 12 miles is this way. Both ways! I can't cost down hill both directions, but using the road to my advantage I need very little pedal power for the total trip.

 Also being as that is where I buy my Gas, I have been in a bind a few times heading to town where I thought I was gonna run out. Hitting the top of one hill at about 55mph, killing the engine and shifting to neutral, I have effectivly coasted over those hills with a 1 ton box truck, and that is a large flat area for lots of wind resistance. On the other hand, I have done that with a little sports car, little weight, low wind resistance, and not made it over the third hill without having to start the engine for power to get up it. Sometimes the added wieght can be an advantage like that box truck, though it sucks the gas when running!

[Dutch]

O-La-La The Chinese Are Coming

Wanna have some pancakes?

http://www.goldenmotor.com/

[Nando]

Nick:

I have built them and I am in the process of building one.

I am installing two heavy duty trailer truck radiator fan motors in a common in line shaft that will couple the energy to the tire rubber under the seat with a pressure pin for coupling/uncoupling the motors from the tire.

The motors under load will use 500 watts at 24 volts.

Coasting will work if you are going down hill, flat land forget it.

Batteries is the next problem, I live in a flat land, Dallas Texas area -- like a pancake-- and just for 5 to 15 miles maximum --

Batteries are heavy and, as well, it will have a PWM charger to charge the batteries in ONE HOUR or less.

I am as well installing a gas engine in the front of the motor, it is 35 years old, Italian and good for more than 100 kilometers per gallon and will have as well a generator to recharge the batteries, this way I am legal, electric power to the wheels.

You need a minimum of 300 watts motor, higher the voltage the better.

Regards

Nando

[elvin1949]

www.heartlandamerica.com

later

elvin

[finnsawyer]

Still, you got it to work.  So, for about 2.5 times the power can you overcome 9 times the wind resistance, not to mention greater mechanical losses?  I'd guess no.

Voltage control.  A rheostat would be wasteful.  Leads one to wonder about a dc to ac conversion fed into a variable output transformer.  (A wiper adds or removes output windings.)  This might be more efficient.

[NickCoons]

I've been looking at this, and everything looks good.  I'm surprised that the price is so low (though shipping from China to the US will be a big part of the cost).  One of the big advantages of something like this is that it actually looks clean.. I'm surprised about that.

I'm looking into finding a used mountain bike locally to start the project.. then as I save up a bit more I'll see if I can order their ebike kit.  I checked on eBay to see if anyone had anything extra.. no such luck :-).

I will keep everyone posted.

BTW, what's the device called that I would connect to the 36V battery to get 12V out of it?  Most portable electronics that I have I've configured to work with the cigarette lighter in my vehicle, so if I could get 12V out of this, I could install a small stereo using a PDA to control it, and various other things.

[ghurd]

Voltage regulator is the simplest. Most only take 40Vmax in I think, so maybe a few diodes for some drop to keep it safe. Bad thing is they are inefficient. 12v, 1a out (12w) needs 1a in, from 36v, is 36w. 36w in gets you 12w out. But they are cheap and easy.

You would be looking for a '7812' voltage regulator.

Switching regulators are much more efficient. Think 36v 0.35a in, gets you 12v 1a out. Complicated to make. Expensive to buy. Unless you can find a 'surplus' one to fit your needs.

G-

[hydrosun]

I've posted about this before. I'm using aerodynamic fairings on my bikes to cut the wind resistance. It increases my speed by 2-3 mph with the same effort. Keeps me alot warmer too.  My light weight road bike goes over 20 mph on the flat, but  the fairing doesn't change speed much on the hills. Most kits for electric bikes have an upper speed under 20mph(by law in most states they have to limit it remain a bicycle) , so these kits wouldn't help much on the flats but would help get up hills. We  have a Currie electric mountain bike that I use to haul heavy loads with a trailer (35 gallons apples up 1/2 mile hill) without slowing nearly as much as before. Of all the electric kits I've seen on the web the one with all the best features was rabbittool.com. It had a 500 watt  brushless motor with regenerative breaking and was using nmh batteries.  Brushless motor are supposed to be 20% more efficient, and they claim up to 95% efficiency. Some chinese brushless motors are about 80% efficient. Pretty pricey and they still are working out the bugs on the controller. Claim to be ready to ship  in the next 2 months.  But if your looking at the best design I think thats the best kit.  For do it yourself  look at staton-inc.com for their gear reducers for gas engines. Seems to be the strongest with chain coupling to a special rear hub with gears on the left and right. So you retain the use of your pedals and the motor goes to the other side.  Bikeengines.com has a simple gear attached to the spokes using a knotched timeing type belt.  Both these last two are using trimmer motors 25cc- 35 cc low mix (50-1 oil) 2 cycle or quieter 4 cycle engines. Some comments from users on bike-engines.com suggest a 35mph on flats and some have over 1500 miles on these rigs.  I saw a homemade fully faired recumbent powered by a trimmer motor last summer. He was travelling around the US. I talked to a guy at the hardware store who had sold him a new motor( after 2000 miles). I don't have the details of type of motor and how heavy the entire rig.

So for now I have a light faired bike I'm comfortable going 40 miles round trip with few hills. But I want to add electric assist that I can take off and on, for hills and for longer rides. For anything over 60 miles or lots of hills or heavy loads I'm thinking about a gas engine assist. But maybe that would qualify as a good use of a normal car.

Chris

[eureka]

Have a look at this web site - V is for Voltage http://www.visforvoltage.com/forums/  they have discussions on all types of electric bikes/trikes/scooters

[(unknown)]

Hi all, I stumbled into this forum while searching for something related to motors.

It's pretty amazing here. The discussions here on motors is fantastic-although you are using motors to make power (electricity). Whereas I frequent electric bike forums like visforvoltage.com and power-assist forum on yahoo.

You can get a nice, cheap electric bike system at wildernessenergy.com. The brushless 400w hubmotor is cheap and very efficient.  I've playing aroung with electric bikes and scooters for a while. I could speak volumes. For example, I bought a we (wilderness energy) pedal first 26" front motor kit brushless, and run it at 48v. It will go 25-27mph depending on how much I pedal for 25miles (at top speed) with 4- 12ah , 12v sla battery.

powerpackmotors.com makes a very good motor to go on currie system available at evdeals.com.

I am waiting for my new 750w brushlees rear hub motor to arrive from China. And then I'll likely opt for new lithium batteries from dlmenergy.com. And it's going on a really nice bike.

www.crystalyte.com

www.evsolutions.net

(distributor)

Anyhow, I made this thing the other day. It has a 24v brushed 250w rear hubmotor. It has 2 12ah 12v batteries (in bag). I fried the controller on something else, so I made my own control system--with built-in electric generator! I push button for straight 24v or 12v (if switched) power. The brake lever has a switch built in so that it switches the patteries to parallel 24ah@12v, and also connects the hubmotor through a diode to the battery to charge the 12v battery, and help slow me down.

The ammeter in picture shows only charging amps. I can easily peg out the meter (12amps max on scale) when hit brake, and recover some of my charge. But the really neat thing is it works great to charge battery. At 24v, it goes about 15mph. I was able to pedal it faster, and get 4amps charging @24v. It is very easy to get 4amps @12v by pedaling only about 10mph. I thought about hoisting it up the flagpole and calling it a windmill. All that is needed now is a centerstand to generate power while not moving. I've gotten this strange feeling now that I have something that doesn't require power from the grid to operate. This was my first experiment at generation. The components are not that great, but they were cheap--about $300 for everything. Easy pedal generator or gravity (downhill) generator.

The crystalyte brushless motors are powerful and very efficient. And also if speed is exceeded or voltage of batteries is switched, the 3 phase dc motor will generate many amps right back into the battery (but not many people use it in this way). The drawback of the brushless motor is it's inability to coast with power off. And also, at low speeds, the pedal=first version (no hall-effect sensors) vibrates like a jackhammer. The brushed hubmotors are very smooth and coast extremely well. A brushed motor @36v = @24mph = brushless (408 model -most common) @48v. Brushed motor gets 1 mile per ah vs. 1.8 miles per ah for brushless (36v vs. 48v). Anyhow, here are pics of my new 120+watt pedal generator. My next generator (bike) will be better; but, it likely won't look this cool...

If you have an interest in electric bike, I encourage you to check out the forums to learn-up on these things before building one from scratch, and then you'll be miles ahead in your journey.

http://www.otherpower.com/images/scimages/4184/chopper_collage.JPG

I couldn't add a pic, so I put link above

Victor