Picture of DIY Electric Bike Conversion
Here is how I used electric bike kits  to convert bicycles into e bikes. Only one e bike conversion is shown here.  

The bikes were older daily rides that needed work and new paint, so this was a chance to fix them up and install the kits all at once. 

Before you get started with a conversion, decide what you want to use as a donor bike, what kind of riding you want to do, the kit you want, and finally the cost. You may be tempted to just get the cheapest kit out there, which might work, but it is best to try and figure out what you want the final conversion to do. 

If you need help in deciding the size of motor and battery pack to use, cruise on over to: http://www.evsroll.com/Electric_Motor_for_Bike.html for details on how much power you need. It is interesting if nothing else. 

Step 1: The E Bike Kit

Picture of The E Bike Kit
Here is the kit used in the conversions. You have a rear wheel motor, controller, thumb operated throttle, on/off switch, brake levers with kill switches (not used), and battery to control cable. 

The motor in this kit is a 500 watt continuous, 1200 watt peak power geared motor especially suited for hills. This motor requires a 22 Amp continuous controller. 

 The brake levers had kill switches on them. Since the throttle is thumb operated, the kill switches and extra wires did not seem necessary. This proved true later on. If you need to stop, you just let go of the thumb throttle, and the motor stops. It is intuitive.

The kits also came with nylon battery bags. These bags are well made, but the battery instructions warn against using these bags! Go figure. 

Cost of Kit: $350
Controller:  $  50 extra 
Total cost for the conversion including the kit, battery, and parts was about $950
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daddy116922 years ago
ty for the reply, everything will fit. I thought the controller would get hot. you think the motor will over heat?
EVsRoll (author)  daddy116922 years ago
It depends on how hard you push the motor. Our 350 Watt motors get hot on real steep slopes. One of them gets so hot that the controller shuts down until it cools off. My new BMC motor hardly ever gets hot...actually never so far. Anyway, you can just stop and touch the motor and or controller and feel the heat. Time to stop if it is too warm.
klehman1 EVsRoll2 months ago
Slap a big I hear sink on the top
GedasN5 months ago

Seems like Rubbee would be a very nice alternative to all the wire hassle.. :)

Rubbe_HQ2 small.jpg

What about using an ammunition box for the battery box? They are cheap to buy in Canada from army surplus stores or flea markets. They take paint easily. Just a thought for anyone doing this great Instructable in the future.

daddy116921 year ago
hi, me again. know anything about getting a rear wheel gear cluster(cassette) apart? I got the special tool, made a fixture with a spare chain to hold the gears. put a 18" breaker bar on the socket and stood on it(300#) & it wouldn't break free.
EVsRoll (author)  daddy116921 year ago
Wow looks like it is froze up...don't want to sound like funny man here, but are you sure you are pulling in the right direction? If not I would take it to a shop and have somebody else at least look at it to check it out....I have had parts stuck so bad I bent the frame getting them off.

BTW there is this really great loosener in a can called PB....it rocks. Maybe try that, let it soak a few days. Good luck!
Best stuff I ever used is called Aero Kroil, by Kano Labs. It is not available in normal stores, because it's labelled industrial use only, but can be had online virtually anywhere.
daddy116921 year ago
hi, I got a universal controller with throttle for my DIY trike. what do I use to keep an eye on my battery charge level? a volt gauge or an amp gauge?
EVsRoll (author)  daddy116921 year ago
Many of the gauges are pricey....no problem if you have the dough...try a Cycle Analyst...at Amazon...$175


I use a gauge from the Hobby King...only about 30 clams delivered. It shows you amp hours since last use, max volts used....the works. It is not adjustable but really works well to get an understanding of your power use...
daddy116922 years ago
hi, I have a diy e trike project. 36v 18ah bat, 750w 27a 2750rpm motor. I'm using a plastic toolbox for a battery box. there's enough room in it for the motor & controller too. would the motor or controller over heat inside the box? thanks
EVsRoll (author)  daddy116922 years ago
Hi: Measure the battery first. Then measure the box. You might have to convert inches to mm or the other way around.

If your controller is in the box it will get warm for sure. Make the box easy to open to cool things off and check on it....better yet put the controller out side of the box.

On my new project, the controller is outside the box...

I just saw this http://www.boostedboards.com/ 
I also saw an article about using the same ( or similar) brushles motors and a lion batterpack do do the same thing for about a $100 bucks, with out board.

I am wondering about using the same components on a bmx bike. Does anybody know if this would work.  Could I wire a potentiometer directly between the batter and motor, instead of a motor controller?
You unfortunately need a motor controller. With a gear reduction motor or a motor with a load already on it, the motor will only start with full power. It needs the full voltage to run. So what the controller does is it sends out rapid fire pulses of the full voltage to the motor so you can vary the speed. You can get a 250 watt motor controller for less than $20 which is a great deal, considering it nearly doubles the quality of the bike if the alternative is to only have an on/off switch.
Also the potentiometer would need to be very high-wattage. But it would still not work.
A bmx might work, but not as well. You should have the ability to shift gears because the motor will be going really fast and you'll want to be in a low, low gear. Even for like 20km/h you still need like gear 1. A bmx would likely only work if you pedaled up to a high speed and then turned on the motor to keep you going on flat land like a cruise control.
Also, a road bike can have a rear cargo rack for holding batteries. If you use lead acid ones, you will want a rack. Lithium might fit on a bmx but not likely.
Thanks, I was hoping it would be easier, but it is never easy is it?
I'm just now wondering about an ebike, and was impressed by your project. A couple of questions, though. 1) Why did you select a rear-wheel drive instead of front-wheel? The front-wheel drive looks easier to install. 2) How did the price jump from $350 for the kit to almost $1000? Are batteries really that expensive? Are there no alternative battery systems? Nice job, though.
i think everyone should have an ebike, i bought mine, but intend converting one myself at some point, i use mine to travel to work, costs 5 pence a day in electric and batteries being lead acid need replacing approx every 6 months costing 140 a year so it costs me approx £2.94 approx a week to get to and from work including battery expenses and charging (though i charge my batteries at work as well) my works is approx 5 1/2 miles away and in a taxi would cost £8.00 e/w the bike cost me £450 so based on the taxi expense the bike paid for itself in under 7 weeks and i normally would only have the option of a taxi on 1 leg of the journey as i work late and the busses arnt much cheaper anyway lol, the bike i have is a bit embarassing to ride lol but the people who might laugh are either walking or spending more on a single bus journey than i do a week or paying more in road tax than i do on the whole thing so secretly im laughing at them lol......ebikes rule
EVsRoll (author)  oldskoolhead2 years ago
Wow, that's great. Thanks for providing your costs...very interesting. Here in the good old USA most people still commute by private car...talk about expensive!
You can't beat a ebike most of the time at least...eBikes Rock!
yellowcatt3 years ago
Thanks for this instructable, I am seriously thinking about converting a bike this year.

Anyone have advice on what type of battery would be best for me to use?

My bike will have an unusual usage pattern because I spend a lot of time out of the country. It would be used regularly for some of the time and then left unused for two or three months at a time when I am working abroad.
hi, sir.
The best type of battery is up to your motor choosing and your bike. Usually, people like to use rear rack lithium battery if you use 48v hub motor. And there is new bottle lithium battery to choose if you like to use 36v hub motor. The rear rack battery can be installed with all bikes. And the botte battery is good fo 26" and 28" male bike. So if you can give me one photo of your bike, that will be a better and exact advice.
Any questions, you can come to cnebikes.

chadeau5 years ago
Allowing for curing,my past experience painting with rattle cans went very well.The paint I used cured into a very durable finish,MTB use and all !!
EVsRoll (author)  chadeau5 years ago
Right on! Good comment, I noticed that the paint did scratch way more easily when it was newly applied, and seems to be getting harder over time...
I remember a few years ago a friend made an 'oven' for baking the frame of a motorcycle he had repainted. It was a large box made out of sheets of OSB with a couple of 500w halogen floodlights inside.
It seemed to work quite well.
chadeau EVsRoll5 years ago
Itching to get my hands on 'Chameleon' paint from Dupli-Color.Wanna purple/green recumbent !
kmalivuk3 years ago
The best way I've found to bend a *steel* frame is:
Thanks for the article. I'm a bicycle mechanic and realize it's time for an e-bike in my commuter bike stable.
A couple of other things you can do to help when painting is to take a hair drier and warm the surface up to body temp before painting and using a few shop lights to "bake" it afterwards. A few light layers of clear also helps. Then hitting it with a buffer and some wax (use a cleaner wax if the the clear is dull, otherwise pure carnuba). If you use cleaner wax or polish, you want the buffer to stay damp.

All in all, cool build!
EVsRoll (author)  audioredneck4 years ago
Thanks for the tips. I need to to some touch up by now. I can tell you that these ebikes are the best little rigs I ever had.

Ben Mighall4 years ago
Hey, how much does this cost and can you still pedal the bike after the "surgery"?
EVsRoll (author)  Ben Mighall4 years ago
Hi Ben:

The complete bike costs around $900-$1,000. This may but seem expensive until you consider that this (and the wife's too) ebike takes me all over the place. It can replace a car for many in town errands. I love the ebike and recommend one to everyone.

Yes, you can pedal in fact much of the time. I have written some pages on the subject since finishing the bike. I explain the pedal assist bike in some detail.

If you are really interested, check here: http://www.evsroll.com/Electric_Assisted_Bicycle.html

markswagan4 years ago
Wattage: 251 - 350w Voltage: 36V Power Supply: Lithium Battery
Wheel Size: Other Motor: Brushless Certification: CE
Frame Material: Aluminum Alloy Foldable: Yes Max Speed: 30-50km/h
Range per Power: > 60 km
Packaging & Delivery
Packaging Detail: CTNS
Delivery Detail ONE WEEK
electric bicycle conversion kit
CCC, CE, ROHS, ISO9001, EN15194
Let's make things better!
electric bicycle conversion kit
24v-10AH LIMN FRONT gear motor 100MM 150w-250w 12"-28"700C 13KG
24v-10AH LIMN FRONT gear motor (100MMwith DISK BREAK ADAPTER) 150w-250w 12"-28"700C 13KG
24v-10AH LIMN REAR gear motor 135mm+6 CLUSER 150w-250w 12"-28"700C 13KG
24v-10AH LIMN REAR gear motor (135mm+6 CLUSER with DISK BREAK ADAPTER) 150w-250w 12"-28"700C 13KG
36v-10AH LIMN FRONT gear motor 100MM 150w-350w 12"-28"700C 16KG
36v-10AH LIMN FRONT gear motor (100MMwith DISK BREAK ADAPTER) 150w-350w 12"-28"700C 16KG
36v-10AH LIMN REAR gear motor 135mm+6 CLUSER 150w-350w 12"-28"700C 16KG
36v-10AH LIMN REAR gear motor (135mm+6 CLUSER with DISK BREAK ADAPTER) 150w-350w 12"-28"700C 16KG
24v-10AH LIMN FRONT direct motor 100MM 200-350w 12"-28"700C 15KG
24v-10AH LIMN FRONT direct motor (100MMwith DISK BREAK ADAPTER) 200-350w 12"-28"700C 15KG
24v-10AH LIMN REAR direct motor 135mm+6 CLUSER 200-350w 12"-28"700C 15KG
24v-10AH LIMN REAR direct motor (135mm+6 CLUSER with DISK BREAK ADAPTER) 200-350w 12"-28"700C 15KG
36v-10AH LIMN FRONT direct motor 100MM 250w-500w 12"-28"700C 18KG
36v-10AH LIMN FRONT direct motor (100MMwith DISK BREAK ADAPTER) 250w-500w 12"-28"700C 18KG
36v-10AH LIMN REAR direct motor 135mm+6 CLUSER 250w-500w 12"-28"700C 18KG
36v-10AH LIMN REAR direct motor (135mm+6 CLUSER with DISK BREAK ADAPTER) 250w-500w 12"-28"700C 18KG

pedalmonkey5 years ago
Hey, nice 'ible. Quick question(s): What's the wheel diameter and spoke count? I have an Xtracycle that I built a bout a year ago and want to electrify it, but I must make sure that the hub motor/wheel assy will bear the intended weight. Right now I have a 26"/40 spoke tandem wheel. I would also like to know what the final (required?) distance is between your dropouts. Thanks, j
EVsRoll (author)  pedalmonkey5 years ago
The wheel with the motor is 26" with a killer deep V alloy rim, and 32, 10 gauge spokes laced 1 cross! That gives you an idea of the strength, it is built almost like a small scooter. Distance from inside dropout to dropout is about 5.7 inches after shimming. The added shims are about 0.4" thick all together. As for required...I found that I needed two shims for sure on the cluster side to keep away from the seat stays. Maybe there is another way, but that worked for me. Opposite the cluster, I needed an additional 0.25" just to center the wheel. The thing is that the motor axles are keyed (flat on 2 sides) to fit tightly in the dropouts to help prevent axle spin from motor torque. This means very little side to side wiggle in centering the wheel like on most bikes.
Groovey. $950 is still a little steep for me right now...however, I was at a small appliance repair shop last week and asked the owner if he ever came across any used DC motors. He gave me two on the spot. Both work and look to be sufficiently beefy for my project, though I will need to buy/scrounge controllers, batteries, etc., for the build. Fortunately, my brother-in-law is a large-scale rep for a major high-end tool manufacturer and will supply me with batteries and chargers for very little money. I just have to find the rest of the components. Gearing and mounting are relatively easy for me as I have a background in (and several spare parts and materials from) aircraft maintenance. The controller looks to be the most expensive thing. Are there any schematics available to home build a controller? I promise to document the build but I'm going to need all the advice and assistance from more educated/experienced individuals that I can find.
EVsRoll (author)  pedalmonkey5 years ago
PedalMonkey: Here may be what you are looking for: http://endless-sphere.com/forums/viewtopic.php?f=2&t=14798 Custom boards for the DIY controller..........
Hey, thanks. I haven't even messed with the motors yet-other projects are underway at present which are even more important. ( mainly the ones my wife sez I have to complete. )
EVsRoll (author)  pedalmonkey5 years ago
Hey Pedal Monkey: Sounds like you have quite the project going. Although I have seen plans for Controllers, I can not remember where....sorry amigo. I would probably shop ebay, they have quite a range on there right now, mostly $25-$50. If I remember right, there was also a guy who used the controller off of a forklift. Another option might be a golf cart since I think a lot of them use a 36 volt set up...lead acid though. Anyway, keep us posted!
I put together a cruiser, a "free radical," (name of the Xtracycle extension), and an e-bike kit. about 5 months ago. Put it on the rear. Works fine. I used their standard 26' kit. It now comes with the capability to use disc brakes. Have about 700 miles on it. No problems. I can haul a lot of stuff, and have done so. Suggest full scale xtracycle kickstand.
EVsRoll (author)  gcruik5 years ago
Thx for the kickstand tip! I am finding out just how heavy these bikes can be when parking them. I'm up to about 250 miles and am totally sold on e bikes. There are soooo many advantages you would not even think of like being able to hit the throttle just in time to scoot of the way of an aggressive or inattentive driver. EVsRock!
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