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Electric bike do it yourself

I was always interested in the topic of electric transport.
And then came the long-awaited moment when I finally moved from theory to practice. I will tell about my experience below.

A couple of thoughts as an introduction.
Why is it now that they are so actively talking about electric cars, electric jets, electric bikes? Finally, the main problem of electric transport was almost resolved - rather compact and capacious batteries began to appear. Moreover, they charge for tolerable time. Actually just waiting for this, everything else has long been created and "run-in" - the body, chassis, electronics, electric motors. All this has been used for hundreds of years. And electric motors allow you to use unusual solutions - for example, to install yourself in the hubs of the wheels themselves.

To the point!

- a bicycle is ordinary, average averaging, the price is about $ 200
- electric motor 48V and power 380W
- 48V and 10A battery
- speed without pedals on a flat road 35-40 km / h
- distance of a trip of 22-25 km on a light hilly district and in the city
- full charge time 2 hours


It should be noted that the conversion is not very striking, and most people on the street just do not notice anything unusual in a bicycle.

The entire kit is purchased in China via eBay. Search kits worth the keyword "ebike, Motor Conversion, kit, LiFePO4." All purchases cost about $ 650 USD shipped from China.
You will have to buy two sets - the KIT itself and the battery.

KIT consists of an already assembled wheel, controller, throttle grip, brake knobs, pedal sensor, headlamp with lock, horn buttons, battery bag.

The second part of the kit is a battery and a charger.

The kits come in 12, 24, 36 and 48 volts and with a capacity of 250, 380, 500 and 1000 watts.
The battery is selected with the appropriate voltage. I would advise not to chase the power. 380W for flat and hilly terrain is enough. Increasing power, the speed will not increase significantly, but it will be better to “pull” uphill.
My personal experience - I very rarely help with pedals and the asterisks stand all the time in the "maximum speed" position.
It is worth noting that in many countries there is a limit of 250W.
Why I chose 48V, I can’t say for sure right now, but in May, when I was combing the Internet before buying, I had a check mark - take only 48V. With the power of the battery, everything is simple - I have 10A, it is 25 km. If you buy a 20A, there will be 50 km of run and 16 kg of battery instead of 8. Decide whether you should carry an extra 4-8 kg of weight if you are not going far away. I understand that power is not measured in amperes, but that is how sellers distinguish them. Not watts / hour, namely voltage / amps.


Wheel motor 4. already assembled. Tire and luggage not included. The wheel should be chosen according to the size of the wheels of your bike, for me it was number 26 - the most common size. If you bought a camera or tire - you know the size for sure.

The main thing to remember when mounting the wheel - the cable must go out of the wheel to the left! Then it will rotate in the right direction. The second and not obvious danger - three thick wires and a few thin ones come out of the wheel. The first thing that a person does when mounting a wheel is that he turns it. The wheel generates electricity, a spark jumps between the power wire and one of the thin wires, and everything, the sensor burned out, pokatushki are canceled. Therefore, taking the wheel out of the box, we immediately wrap these wires with tape and until they are connected to the controller, we hold them.
It may be necessary to slightly undermine the seat on the fork and the axle on the wheel, I did it. Dremel and a few cutting discs were enough to mount the wheel.
Here you need to be as careful as possible, the denser the wheel will sit in its place, the less problems will be in the future. Do not waste too much. Owners of expensive bikes with aluminum forks should choose the rear wheel, I read how a powerful kilowatt wheel just broke a mustache on the fork when it was triggered. The front fork is designed for load up and back, and the wheel pulls forward and in a circle. But the motor on the rear wheel gives the load on the frame is not different from the pedals.


The controller is a small aluminum box 3. with a bundle of wires. There are no special problems with it. Find a comfortable place on the frame and fasten. I successfully turned on the bottom beam two bolts just screwed into the frame. On one of them, I hung up the controller, the second did not match and I fixed it with a plastic strip. It is necessary to stock them, an indispensable thing for fixing cables.


The only remark. Due to legal speed limits in some countries there is a lock in the controller. Most often it is a wire that just needs to be opened. A locked controller will not allow accelerating faster than 25 km / h.



First you need to replace the brake handle. I did not change the front brake lever. Replaced only the back. Why do I need to change? In the handle is a contact that turns off the electric motor at the time of braking.

Second, on the left side of the steering wheel, you must install the throttle grip. Remove the rubber handle, cut it from the inside to the desired width. We put everything in its place.

Third, you need to install the headlamp. In the headlamp is "ignition" and a beep. I did not connect the beep button, I can and so poorat. But a couple of keys are very pleased. The key replaces the power switch, and a further turn on the headlight. It's comfortable. Pulling the key out of the headlamp without turning off the bike will fail. The bike is quite heavy, and the pedal travel is also not so simple (after all, they are at the maximum and you still have to turn the engine, which in this case becomes a generator) - it will not be so easy for the thief to jump and ride on your bike. Even just roll it off in your hands. This allows not too much "strain" distracting from the bike for a few minutes and not to fasten it every time with a lock.
In the photo it is noticeable that the headlight is made of cheap plastic and began to wipe from the rubberized cable of the gears.
LEDs in theory should indicate the degree of battery discharge. Perhaps on the lead it is, but on a LiFePO4 battery it does not work. First, the full charge is on, then the red LED - the battery is empty. In addition, these are superlight LEDs and they are trite at night in the face, and they also interfere in the daytime. Therefore, there is this strip of adhesive paper. Then I swipe the tips of the LEDs and drip on top of a drop of hot melt to get just a frosted glow.

I mentioned that the kit has a sensor on the pedals. I did not put it. It replaces the gas handle. Starting to pedal you turn on the engine, but it only helps to drive. No more, I think it should be quite economical, but I was not interested.


As I wrote this is a kind of lithium battery. LiFePO4 - it is cheaper than its counterparts from cell phones, does not explode, gives up large currents well, charges quickly, has up to 1500 charge-discharge cycles before the beginning of a noticeable decrease in capacity. Such batteries appeared only a year or two ago and are still little known on the market.
The Chinese themselves collect them from individual elements of the required voltage, power and size.


In addition to the battery in the bag is charge balancer charge. From it comes a bundle of wires into the battery itself. Ie, the battery is charged in parts and the individual "banks" of the elements are balanced among themselves.

Why not the usual lead-acid battery? Similar to the parameters of my battery will weigh more than 20 kg. There will be a fuss with electrolyte, long charging, the number of charge-discharge cycles is no more than a thousand, but only a hundred or two. Moreover, if I go to buy such batteries in my store, it will cost not much less. So even for the money I do not vygadayu.

The device in the apartment is charging. A full charge takes two hours, charging is light and relatively small, you can throw in a backpack and charge the bike on the road. In a roadside cafe for example or at a gas station.


Impressions of riding such a bike are indescribable. The sound of the motor is not audible. On the track you fall into a trance. Feeling akin to how I felt flying in a dream. Uniform, silent movement through space. In the city, drivers get in the way. They move slowly, get under way for a long time. In the fields of the front wheel rushing perfectly, but the battery sits quickly.

What is nice is that the rights are not needed, insurance is not needed, it is rolled into the apartment, it does not smell like gasoline.

Source: https://habr.com/ru/post/102000/

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