Picture of How to build an electric bike for less than $100
Yes, it is actually possible to build an electric bike for under $100. The secret to doing this is... get most of your materials for free! Now I am not just going to turn you lose and say go find this stuff either. There are a few tricks and tips that I will give you and places to look. In addition, you will need to have problem solving skills of your own, since everything you get will probably be a little different from what I have. Undertaking this project is going to be challenging, and if you do not have substantial knowledge of machining tools, you might as well back out now. However, if you know your way around a lathe and are handy with only a few simple tools, this project is something you can complete in a few months working in only your spare time. This is also my entry into the Epilog Laser Cutter challenge, so please do not forget to rate and vote! Also, if you have any suggestions on things I can add to make this better, PLEASE comment, as I will be handing this in for a very important grade (basically my whole 4th quarter grade) so any criticism and help would be greatly appreciated! Thanks!
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etrikebikes4 years ago
Whoa my young friend,

I applaud your ingenuity, get up and go, and skills, but if I were grading this project I would start from C and go down from there, on the basis of your design goals. You simply cannot put all that extra weight including 2 honkin' lead acid batteries on a cheap bike frame and go 40 mph without frightful safety concerns. Even the Federal e-bike limit of 20 mph is too fast for this project. Limit it to 12-15 mph and you will be infinitely safer and go at least 4 times as far on a charge. Then you'd start with an A in my book.

Making your own personal electric transportation for $100 is not worth heavy duty injury or your life, and that is just what you risk.
It's a good thing you are not grading him then. While safety is a concern, it's not as much as most people think.
The federal limit is bullcrap, I can pedal faster than that, the government wants to hold your hand for everything.
The fact is he is being graded on his skills, ingenuity and ability to critical think, not to where a safety harness and ask the government to hold his hand ffs this is why we are in such economic debt.

You might feel comfortable promoting dangerous activity by yourself and your neighbors for the sake of an ultra-libertarian ideology, but I'm not. The federal limits for an e-powered bike to stay within the confines of an unlicensed, uninsured vehicle, that is still considered a bicycle, are quite reasonable, which is why most states are now following them. The European limits are about 30% more stringent, so count us lucky.

I don't have a car anymore. For the last 3 & a half years my personal transport (around Chicago) has been an e-trike that is Federal and state legal. Even at the lowly 20mph I'm on average as fast as automobiles around town except for the expressways, which often aren't very express. It cost me about 10 times this project to put together new from kit, making my own battery packs, using barely more than $50 worth of hand tools. I don't have to fear hundreds of dollars of fines for going illegal and that extra cost was long ago amortized out. See us in action at www.etrikebikes.com, ,"E-bike Shopping in Winter."

This was a fabulous garage project for perhaps the track, and Mechanical Engineer should be applauded on that basis. It's not appropriate to the street because so much weight on such a slight frame would be close to uncontrollable in emergency at federal limits and downright crazy at twice federal speed limits for e-bikes. The federal nanny is doing a good job! I prefer her to an early grave which is possible enough to get when mixing it up with 2 ton SUVs or worse..
I think I will build one with the power chair motor and bicycle. No lectures about safety- I already have titanium in my spine. I will take responsibilty for my own safety. I've also got a Honda 750 motorcycle engine I plan to put on a regular go kart. That ought to be fun!!!
Regarding your comments "much weight on such a slight frame would be close to uncontrollable in emergency" and "twice federal speed limits for e-bikes".

Regarding weight and control, I have a similar weight engine assembly on a similar bicycle and there are no control problems. So in my experience this bicycle should have no control problems. Regarding the legality of this bicycle, there are more powerful ebikes sold in stores and the stores aren't getting busted. So I don't think this is an illegal bicycle design. Normal bicycles break federal bicycle speed limits, it's also illegal to flick boogers into the wind in Alabama, America has a lot of unenforced laws on the books. I think it's unlikely police would have a litigious hissy fit over this bike.

Well said, mate.

lucek5 months ago

Was looking at this but when I did found out that my state considers this a moped and thus requires registration and drivers licence(I have none. Reason I was looking at electric bikes).

JeevaB6 months ago

Hi, My friend which size bearing you used?

allan.moffat9 months ago

The plastic pipe held on by sticky tape for use as a foot rest looks UNSAFE ! , may I suggest using a pair of stunt pegs on the front axle ?

Then you will be able to steer this bike using your feet whilst reading the morning paper on the way to work.

Hey by any chance, do you know what the output for the motor you used was?

as far as horsepower or wattage, I do not. I just kinda took what I could get. All I know is that it is a 24 volt electric powerchair motor. If I had to take a wild guess, I'd say around 300-500 watts.

mohd_owais1 year ago

hi .. guys .. actually I have a project of my exam and I need to build an electric bicycle . so if any of u who know how to do it plzz .. can u help me out .. I need the instruction for building the electric bicycle ..

I give this project an A+ because I would pay $150 - $300 for a kit like this, batteries not included. The only thing I would want done differently for a kit would be for the connection to the center frame to use u-bolts, maybe with holes in the plate for different size frames.
dddddd4 years ago
Yes, a hundred dollars in parts,
but over a thousand dollars in tools.

It often turns out like that.

I could do it without "a thousand dollars in tools".

* I would would do any welding using brazing instead which would cost me less then $30 for all new brazing tools from the store.

* I would use fiber added to clay and (zinc or aluminum) for casting any parts. A propane torch + two tuna cans + pliers + zinc + clay + (cotton balls or flour to prevent clay cracking) and all that would be less then $30.

* Motors often have brass fittings on the shaft. I would either braze onto that or melt zinc to connect the pully to the motor. Or I would use the brazing to build a socket for the motor if the shaft was contained iron (which would be removable). Any of these methods would be low temperature enough to not damage the motor.

* And if I needed a lathe I just rig one using my drill, possibly using wax and then casting the part as above. A drill, coat hanger wire and wax would all cost less then $20.

I think that you're right, the author did not think much about how to control tool costs. But with a little planning, I believe this project could be done for 10% of what you think the tool cost are.
Welding is stronger than brazing no? Going 40 mph top speed i'd like to know it's as strong as possible.
No, it's not a strength issue. Both welding and brazing are very strong and both methods result in a seam that is usually stronger then the surrounding metal. But each method has advantages and disadvantages depending on what you are making. Some metals like aluminum are difficult to weld but easy to braze. Brazing can be more expensive depending on how much work needs to be done. One of the main differences in what method you should use is size of the metal piece you are fixing. Large metal pieces are hard to braze because it's hard to maintain the right temperature range for brazing, but would be easy to weld. So for example, if you're fixing a 7 inch brass propeller, gear, engine casing, aluminum kickstand, with stuff like that brazing will work great. But if you're fixing a huge anchor, the hull of a ship, a steel car frame or engine block, in those cases regular welding equipment would be the best technique to use. http://news.thomasnet.com/IMT/2005/01/18/welding_vs_braz/ Anyway, I love this instructable. But the battery holders and motor mount could definitely be made without a welder.
Ah thank you for clarity in your post. I had actually seen brazing that is just as strong if not stronger than welding however did not know the requirements to make such a strong joint.
Another thing, if you used a smaller motor support plate and moved the location of that motor plate you could use u-bolts for mounting that motor plate to the bicycle frame. They sell pulleys for attaching to bicycles so the pulley adjustment doesn't have to be on the motor support plate. I have a friction motor bicycle and the engine is connected above the back wheel to the frame with just bolts and there are a lot of motor bicycles out there that use pulleys. Here's a picture of friction motor mounted above the back wheel. http://i00.i.aliimg.com/photo/v1/763275826/Rear_Friction_bicycle_motor_kit.jpg Also however you connect things, I'd suggest using superglue or lock-tight compound so the nuts don't loosen up from vibration. To further reduce welding requirements, Bicycle saddle bags or side baskets might be an easier way to store the batteries then making custom holders. There are plenty of DIY projects out there if you want plans to make bicycle saddle bags.
lol Right on !
when i saw the rest of his pictures, I find yes, it is :0)
You are 100% right.
BtheBike dddddd4 years ago
plenty of local tool co-op kitchens all over . one can also 'wardrobe' tools, which is : buy , use , return .

Where da pedals at? =/
Thats what hackerspaces are for!
Here in Texas you can't do this. It can be an assisted device- the pedals have been removed therefore it becomes a motor driven vehicle. Instead do what I did- http://www.fiveflagsmotorbikes.com/ElectricBicycleMotors.htm It's less than 450.00 and IT REALLY REALLY WORKS! I've got mine up to 12 gear and 45MPH! Takes three hours to recharge with a range of 20 miles un-assisted (no pedallling) and up to 35 miles assisted @ 10mph. Uses three deep cell 12 volt batteries. Been using it since 2008 with no problems.
Interesting enough the top speed for e-bikes in the US is 20 something miles p h. So while you say you "Can't" do this your doing something you're advocating to do something your not supposed to do anyways.
i think that pedal rule it prolific in the U.S. to be considered a 'bicycle' . Hub motors are great ,yes. I really think though that more research should be done with the 'chain drive' design like this. It takes advantage of the gears
thanks for the input- I got mad at $4.00 gasoline and wanted to do something about it. It's actually faster on my bike than riding in my car to my 9 mile communte. With the hub I can get to work in as little as 15 minutes- I use bike paths and back streets with little traffic. the one thing that really helps are KEVLAR TIRES they have saved me from falls several times. Regards, M
Ha! yes I have a bionx hub kit . actually beat friends from a-to-b more than a few times. One friend was impressed enough to buy his own last year. it has gotten me in good enough shape to commute by single speed bmx .

How have the kevlar tires kept you upright ? You mean from having a blowout? 1 Thing i've used is tire liners . This way ,one can reuse it with any cheap tire.
I once beat an ambulance with it's siren wailing across the 59th street bridge between Queens and Manhattan, without power assist. Of course that says more about rush hour traffic across the 59th Street Bridge than anything else.
Wow I use to live in Little Ferry NJ! Great Stuff Thanks.
yep , rush hour is 1 thing that inhibits cars. Then you have traffic lights , stop signs , cross walks,sidewalks, grass, dirt, curbs, one way streets , school zones , etc... . I knew of 1 friend who got a speeding warning on a human powered bike going 40 downhill in a 25mph zone but this is super rare .

My a-to-b example was during Non-rush hour . I sweat very little to beat cars home but I would have sweat a lot more without assist.

Wow great stuff. Here in houston we have lots of pot holes uneven roads, wierd expansion joints in the roads and sidewalks. So if I was using regular tires- either a blow out or bent wheel
i've used kelar with the additional tire liner too . With the 2 in concert , I've never gotten a puncture in over 1000 miles ,But I have pinched the tube a few times . With the economy some roadways are going unrepaired , personally i usually pop tubes on curbs .

I like your (Crystalyte?) rig . Steel and sturdy . Not likely to get ripped off =) .
You get it going over 35 + mph on flat roads ?! Thats awesome. Bionx peaks at
25 mph but I'm more than happy with it.

you see this ?http://www.youtube.com/watch?v=jmPUze3WBTw&
ABSOLUTLEY A W E S O M E! I I use to race motorcycles when I was a teenager- Feel The Need For Speed! I like to see the looks on recumberant cyclists when I pass them like they're standing still- very fun they just can't figure it out. Great stuff thanks!
eeglinton3 years ago
As a Major priority you should ditch the standard caliper brakes with rubber blocks and scrounge a pair of disc brakes. You are aiming for road speeds close to your national open road limit.
In addition normal bike helmets just don't cut it at these speeds get and use a full face motorcycle lid.
This is good advice. I really don't think he'll be doing 40mph consistently, just because he has the top speed to do so.
mlt342 years ago
This certainly is a cheap eBike build. For anyone that wants a higher quality ebike though, I recommend building one yourself using the guide at www.UltimateEbikeEbook.com since I found it so helpful.
Could you post an instructable? Will it cost us over a 100$ with over 1000$ in tools?
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