How To Make An Electric Scooter Chain Sprocket With Nothing But Hand Tools

Sometimes, mechanical parts can be supremely expensive, or totally unavailable. In those cases, there’s just one option — make it yourself. It was this very situation in which I found myself. My electric scooter had been ever so slightly bested by a faster competitor, and I needed redemption. A gearing change would do the trick, but alas, the chain sprocket I needed simply did not exist from the usual online classifieds.

Thus, I grabbed the only tools I had, busied myself with my task. This is a build that should be replicable by anyone comfortable using a printer, power drill, and rotary tool. Let’s get to work!

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Cheap Electric Scooter Gets A Big Brake Upgrade; Unlocks Proper Drift Mode

The last few years have seen a huge rise in the prominence of electric scooters. Brushless motors, lithium batteries, and scooter sharing companies have brought them to the mainstream. However, electric scooters of a variety of designs have been around for a long time, spawning a dedicated subculture of hackers intent on getting the best out of them.

One such hacker is yours truly, having started by modifying basic kick scooters with a variety of propulsion systems way back in 2009. After growing frustrated with the limitations of creating high-speed rotating assemblies without machine tools, I turned my eye to what was commercially available. With my first engineering paycheck under my belt, I bought myself a Razor E300, and was promptly disappointed by the performance. Naturally, hacking ensued as the lead-acid batteries were jettisoned for lithium replacements.

Over the years, batteries, controllers and even the big old heavy brushed motor were replaced. The basic mechanical layout was sound, making it easy to make changes with simple hand tools. As acceleration became violent and top speeds inched closer to 40 km/h, I began to grow increasingly frustrated with the scooter’s one glaring major flaw. It was time to fix the brakes.

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Liberating Birds For A Cheap Electric Scooter

A few months ago, several companies started deploying electric scooters on the sidewalks of cities around the United States. These scooters were standard, off-the-shelf electric scooters made in China, loaded up with battery packs, motors, and a ‘brain box’ that has a GPS unit, a cellular modem, and a few more electronics that turn this dumb electric scooter into something you can ride via an app. Dropping electronic waste on cities around the country was not looked upon kindly by these municipalities, and right now there are hundreds of Bird and Lime scooters in towing yards, just waiting to be auctioned off to the highest bidder.

This is a remarkable opportunity for anyone who can turn a screwdriver and handle a soldering iron. For mere pennies on the dollar you can buy dozens of these scooters, and you can own thousands of dollars in batteries and electronics if you show up to the right auction. [humanbeing21] over on the scootertalk forums is preparing for the Bird apocalypse, and he’s already converted a few of these scooters to be his personal transportation device.

The subject of this conversion are scooters deployed by Bird, which are in actuality Xiaomi MIJIA M365 scooters with a few added electronics to connect to the Internet. The ‘conversion kit’ for a Bird scooter comes directly from China, costs $30, and is apparently a plug-and-play sort of deal. The hardest part is finding a screwdriver with the right security bits, but that again is a problem eBay is more than willing to solve.

Right now, [humanbeing21] is in contact with a towing company that has well over a hundred Bird scooters on their lot, each accruing daily storage fees. Since these scooters only cost about $400 new, we’re probably well past the time when it makes sense for Bird to pay to get them out of storage. This means they’ll probably be heading for an auction where anyone can pick them up — all of them — for a hundred bucks or so.

Right now, scooter hacking is becoming one of the most interesting adventures in modern-day hacking. You’ve got batteries and electronics and motors just sitting there, ready for the taking (and yes, through these auctions you can do this legally). We’re looking at a future filled with 18650-based Powerwalls from discarded electric scooters and quadcopters built around scooter motors filling the skies. This is cyberpunk, and we can’t wait to see the other builds these scooters will become.

Building An Electric Scooter That’s Street Legal, Even In Germany

Sometimes a successful project isn’t only about making sure all the electrons are in the right place at the right time, or building something that won’t collapse under its own weight. A lot of projects involve a fair amount of social engineering to be counted as a success, especially those that might result in arrest and incarceration if built as originally planned. Such projects are often referred to as “the fun ones.”

For the past few months, we’ve been following [Bitluni]’s DIY electric scooter build, which had been following the usual trajectory for these things – take a stock unpowered scooter, replace the rear wheel with a 250 W hub motor, add an ESC, battery, and throttle, and away you go. Things took a very interesting turn, however, when his street testing ran afoul of German law, which limits small electric vehicles to a yawn-inducing 6 kph. Unwilling to bore himself to death thus, [Bitluni] found a workaround: vehicles that are only assisted by an electric motor have a much more reasonable speed limit of 25 kph. So he added an Arduino with a gyro and accelerometer module and wrote a program to only power the wheel after the rider has kicked the scooter along a few times – no throttle needed. The motor stops after a bit, needing another push or two to kick it back on. A brake lever kills the motor, as does laying the scooter on its side. It’s quite a clever design, and while it might not keep the Polizei at bay, you can’t say he didn’t try.

[Bitluni] has quite a range of builds, from software-defined television to bad 3D-scanners to precision wine glass whacking. You should check out his stuff. Continue reading “Building An Electric Scooter That’s Street Legal, Even In Germany”

Converting An Electric Scooter To Lithium Batteries And Disabling The Safeties

There’s a bunch of different electric scooters available nowadays, including those hoverboards that keep catching fire. [TK] had an older Razor E300 that uses lead acid batteries. After getting tired of the low speeds and 12 hour charge times, [TK] decided it was time to swap for lithium batteries.

The new batteries were sourced from a Ryobi drill. Each provides 18 V, giving 36 V in series. The original batteries only ran at 24 V, which caused some issues with the motor controller. It refused to start up with the higher voltage. The solution: disable the safety shutdown relay on the motor controller by bridging it with a wire.

With the voltage issue sorted out, it was time for the current limit to be modified. This motor controller uses a TI TL494 to generate the PWM waveforms that drive a MOSFET to provide variable power to the motor. Cutting the trace to the TL494’s current sense pin removed the current limit all together.

We’re not saying it’s advisable to disable all current and voltage limits on your scooter, but it seems to be working out for [TK]. The $200 scooter now does 28 km/h, up from 22 km/h and charges much faster. With gearing mods, he’s hoping to eke out some more performance.

After the break, the full conversion video.

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Electric Scooter MK 1 — Tundra Upgrade!

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After discovering his all-terrain snow scooter was terrible on ice — [Dane] decided he needed to do some upgrades.

In case you don’t remember, we first shared [Dane’s] project back in December, where he zipped around city streets covered in snow. The scooter used a big knobby tire and a front ski to slide around on. To make it suitable for ice, he had to redesign it a bit to handle slippery surfaces; he needed to give it skates.

He had originally hoped to find figure skates at a thrift store (where he originally found the classic scooter), but had no luck — so he made his own. Some 1/2″ x 1/4″ steel bar later, a bit of welding, and he had a rather rugged front skate to work with!

After he was content with his upgraded front-end, he started adding studs to the back tire. He’s using plain old 3/8″ self tapping screws, and a whole lot of epoxy to make sure they stay in.

So does it work? Oh yeah.

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3kW Electric Scooter

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[Exco] had been playing around with the idea of building an electric scooter for a while now, and over the holidays he decided to just do it.

Similar to the motorized long board we shared last month, this scooter makes use of an RC hobby motor — in this case, a 63mm 3kW brushless outrunner (for a RC plane), coupled with a 100A ESC. He bought the scooter (“kick board”) off eBay for cheap, and spent a few days in the machine shop modifying it. It has better wheels now, and custom milled aluminum brackets for mounting the motor. The drive system uses a belt and pulley with a sliding rail to provide tensioning.

To power it, he bought a bunch of 2.5Ah, 18V LiPo packs on eBay originally from a Makita drill set. He then sorted out the cells, removed the dead ones, and soldered everything together for his own Frankenstein pack to balance them. The final configuration features twenty-one 18650 lithium cells. He even shrink wrapped it, which makes it look relatively professional!

It’s controlled by a push-button potentiometer hooked up to the ESC. Theoretical top speed is about 27km/h @ 1285RPM, and they managed to get it up to 25km/h in a real test. There’s more info over at the Endless Sphere forum, and we’ve got two test videos for you after the break.

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