ebike

50 Articles

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AC Motor Converted Into DC EBike Powerplant

January 15, 2026 by 5 Comments

AC induction motors are everywhere, from ceiling fans to vehicles. They’re reliable, simple, and rugged — but there are some disadvantages. It’s difficult to control the speed without complex electronics, and precisely placing the shaft at a given angle is next to impossible. But the core of these common induction machines can be modified and rewired into brushless DC (BLDC) motors, provided you have a few tools on hand as [Austin] demonstrates.

To convert an AC induction motor to a brushless DC electric motor (BLDC), the stator needs to be completely rewired. It also needs a number of poles proportional to the number of phases of the BLDC controller, and in this case the 24-pole motor could accommodate the three phases. [Austin] removed the original stator windings and hand-wound his own in a 16-pole configuration. The rotor needs modification as well, so he turned the rotor on a lathe and then added a set of permanent magnets secured to the rotor with JB Weld. From there it just needs some hall effect sensors, a motor controller and power to get spinning.

At this point the motor could be used for anything a BLDC motor would be used. For this project, [Austin] is putting it on a bicycle. A 3D printed pulley mounts to the fixed gear on the rear wheel, and a motor controller, battery, and some tensioners are all that is left to get this bike under power. His tests show it comfortably drawing around 1.3 kW so you may want to limit this if you’re in Europe but other than that it works extremely well and reminds us of one of our favorite ebike conversions based on a washing machine motor instead of a drill press.

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Saving A Rental Ebike From The Landfill

November 23, 2025 by 21 Comments

One of the hardest things about owning a classic car is finding replacement parts. Especially if the car is particularly old or rare, or if the parent company is now out of business, sometimes this can be literally impossible and a new part will have to be manufactured from scratch. The same is true of bicycles as well, and there are plenty of defunct bicycle manufacturers to choose from. [Berm Peak] found a couple old rental ebikes from a company that’s not in business anymore and set about trying to get them working again. (Video, embedded below.)

Of course, unlike many classic cars, ebikes are encumbered by proprietary electronics and software that are much harder to replace than most physical components. As a result, these bikes get most of their electronics pulled out and directly replaced. This bike also had a seized motor, so [Berm Peak] replaced it with another hub motor he had in his shop. Some of the other highlights in the build include a custom 3D-printed latching mechanism for the battery’s attachment point at the frame, a 3D printed bezel for the new display and control unit, and the reuse of some of the other fun parts of the bike like the front basket and integrated headlight.

There are a few reasons for putting so much work into a bike like this. For this specific bike at least, the underlying components are worth saving; the sturdy metal frame and belt drivetrain are robust and won’t need much maintenance in the long term. It also only cost around $500 in parts to build a bike that would take around $2,000 to purchase new, so there’s some economic incentive as well. And in general it’s more fun and better for the world to fix things like this up and get them running again rather than buying something new off the shelf. And while proprietary electronics like those found on this bike are ubiquitous in the ebike world, they’re not all completely closed-source.

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Making The World’s Smallest E-Bike Battery

September 1, 2025 by 25 Comments

Often times, e-bikes seek to build the biggest battery with the most range. But what if you want to take a couple lunch loops on your bike and only need 20 minutes of charge? That’s [Seth] from Berm Peak set out to find out with his minuscule Bermacell battery.

The battery is made from only 14 18650s, this tiny 52V batty is nearly as small an e-bike battery as can be made. Each cell is 3000 mAh making a total battery capacity of 156 Wh. All the cells were welded in series with an off the shelf BMS and everything was neatly packaged in an over-sized 3D printed 9V battery case. [Seth] plans to make another smaller battery with less then 100 Wh of capacity so he can take it on a plane, so stay tuned for more coverage!

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The Nightmare Of Jailbreaking A ‘Pay-To-Ride’ Gotcha Ebike

May 19, 2025 by 37 Comments

Theoretically bicycle rental services are a great thing, as they give anyone the means to travel around comfortably without immediately having to rent a car, hail a taxi or brave whatever the local public transport options may be. That is until said services go out of business and suddenly thousands of increasingly more proprietary and locked-down e-bikes suddenly are at risk of becoming e-waste. So too with a recent acquisition by [Berm Peak] over at YouTube, featuring a ‘Gotcha’ e-bike by Bolt Mobility, which went AWOL back in 2022, leaving behind thousands of these e-bikes.

So how hard could it be to take one of these proprietary e-bikes and turn it into a run-off-the-mill e-bike for daily use? As it turns out, very hard. While getting the (36V) battery released and recharged was easy enough, the challenge came with the rest of the electronics, with a veritable explosion of wiring, the Tongsheng controller module and the ‘Gotcha’ computer module that locks it all down. While one could rip this all out and replace it, that would make the cost-effectiveness of getting one of these go down the drain.

Sadly, reverse-engineering the existing system proved to be too much of a hassle, so a new controller was installed along with a bunch of hacks to make the lights and new controller work. Still, for $75 for the bike, installing new electronics may be worth it, assuming you can find replacement parts and got some spare hours (or weeks) to spend on rebuilding it. The bike in the video costed less than $200 in total with new parts, albeit with the cheapest controller, but maybe jailbreaking the original controller could knock that down.

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Hydroelectric Generator Gets Power From Siphoning

January 21, 2025 by 42 Comments

Siphons are one of those physics phenomena that, like gyroscopes, non-Newtonian fluids, and electricity, seem almost magical. Thanks to atmospheric pressure, simply filling a tube with liquid and placing the end of the tube below the liquid level of a container allows it to flow against gravity, over a barrier, and down into another container without any extra energy inputs once the siphon is started. They’re not just tricks, though; siphons have practical applications as well, such as in siphon-powered hydroelectric turbine.

This is an iteration of [Beyond the Print]’s efforts to draw useful energy from a local dam with an uneconomic amount of water pressure and/or volume for a typical hydroelectric power station. One of his earlier attempts involved a water wheel but this siphon-based device uses a more efficient impeller design instead, and it also keeps the generator dry as well. Using 3″ PVC piping to channel the siphon, as well as a short length of thinner pipe to attach a shop vac for priming the siphon, water is drawn from the reservoir, up the pipe, and then down through the impeller which spins a small DC generator.

This design is generating about 9 V open-circuit, and we’d assume there’s enough power available to charge a phone or power a small microcontroller device. However, there’s a ton of room for improvement here. The major problem [Beyond the Print] is currently experiencing is getting air into the system and having the siphon broken, which he’s solved temporarily by adding a bucket at the outflow. This slows down the water though, so perhaps with any air leaks mitigated the power generation capabilities will be greatly increased.

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E-Bike Motor Gets New Life As Hydro Plant

January 5, 2025 by 52 Comments

For economic reasons, not every lake with a dam can support a hydroelectric power plant. Some rivers or creeks are dammed for flood control or simply for recreation, and don’t have the flow rate or aren’t deep enough to make the investment of a grid-scale generation facility worthwhile. But for those of us with a few spare parts around and access to a small lake, sometimes it’s possible to generate a usable amount of energy with just a bit of effort.

[Beyond the Tint] is building this mostly as a proof-of-concept, starting with a 1,000W hub motor from an e-bike that’s been removed from its wheel. A 3D-printed waterwheel attachment is installed in its place, and the fixed shaft is attached to a homemade ladder-looking mechanism that allows the entire generator to be lowered into the flow of a moving body of water, in this case, a small stream. A bridge rectifier converts the AC from the hub motor (now a generator) into DC, and after a few measurements and trials, [Beyond the Tint] produced over 30W with the first prototype.

A second prototype was made with feedback from the first video he produced, this time with an enclosed paddlewheel. This didn’t appear to make much difference at first, but a more refined impeller may make a difference in future prototypes. Small-scale hydropower is a fairly popular challenge to tackle, especially in the off-grid community. With access to even a small flowing stream and enough elevation change, it’s possible to build something like this generator out of parts from an old washing machine.

Continue reading “E-Bike Motor Gets New Life As Hydro Plant” →

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Disposable Vape Batteries Power EBike

November 7, 2024 by 14 Comments

There are a lot of things that get landfilled that have some marginal value, but generally if there’s not a huge amount of money to be made recycling things they won’t get recycled. It might not be surprising to most that this is true of almost all plastic, a substantial portion of glass, and even a lot of paper and metals, but what might come as a shock is that plenty of rechargeable lithium batteries are included in this list as well. It’s cheaper to build lithium batteries into one-time-use items like disposable vape pens and just throw them out after one (or less than one) charge cycle, but if you have some spare time these batteries are plenty useful.

[Chris Doel] found over a hundred disposable vape pens after a local music festival and collected them all to build into a battery powerful enough for an ebike. Granted, this involves a lot of work disassembling each vape which is full of some fairly toxic compounds and which also generally tend to have some sensitive electronics, but once each pen was disassembled the real work of building a battery gets going. He starts with testing each cell and charging them to the same voltage, grouping cells with similar internal resistances. From there he assembles them into a 48V pack with a battery management system and custom 3D printed cell holders to accommodate the wide range of cell sizes. A 3D printed enclosure with charge/discharge ports, a power switch, and a status display round out the build.

With the battery bank completed he straps it to his existing ebike and hits the trails, easily traveling 20 miles with barely any pedal input. These cells are only rated for 300 charge-discharge cycles which is on par for plenty of similar 18650 cells, making this an impressive build for essentially free materials minus the costs of filament, a few parts, and the sweat equity that went into sourcing the cells. If you want to take an ebike to the next level of low-cost, we’d recommend pairing this battery with the drivetrain from the Spin Cycle.

Thanks to [Anton] for the tip!