An Open Source Ebike

In the ebike world, there are two paths. The first is a homemade kit bike with motors and controllers from China. The second is a prebuilt bike from a manufacturer like Giant, with motors and controllers from China, which will be half as fast and cost three times as much. The choice is obvious, and there are other benefits to taking the first path as well, such as using this equipment which now has an open source firmware option.

The Tong Sheng TSDZ2 drive is popular in the ebike world because it’s an affordable kit motor which has a pedal-assist mode using torque sensors, resulting in a more polished experience. In contrast, other popular kit motors tend to rely on less expensive cadence sensors which are not as smooth or intuitive. This new open source firmware for the TSDZ2 further improves on the ride by improving the motor responsiveness, improving battery efficiency, and opening up the ability to use any of a number of color displays. (More information is available on a separate Wiki.)

If you have a TSDZ2-based ebike it might be time to break out the laptop and get to work installing this firmware. If you’re behind the times and still haven’t figured out that ebikes are one of the best ways to travel, here is the proof you need.

Thanks to [coaxial] for the tip! Photo via Reddit user [PippyLongSausage].

A High Performance Ski-Sled For The Big Kids

Sledding is a pastime often left to younger humans, though there is no good reason why this must be the case. [JoshXarles] is an adult with a strong enthusiasm for carving up the snow, and set out to build a high-performance sled this winter. 

It’s a ski-based design, and [Josh]’s goal from the outset was to build a rig with serious handling credentials. His favored run features several 180 degree switchbacks, so it’s important to be able to corner well without losing speed. This was achieved by using sidecut skis with a carefully designed steering system, allowing the sled to carve corners in the same way as a downhill skier. The frame of the sled is built out of aluminium box tubing, bolted together to form a strong structure. There’s also attractive wooden decking which completes the look.

The sled performed admirably in initial testing, with good steering feel and plenty of speed downhill. We’d love to try ourselves, weather permitting, of course. There are also electric options for those not blessed with geologically-suitable features to sled down. Video after the break.

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Fun-Size Tesla Might Be The World’s Smallest

We get all kinds of tips about “the world’s something-est” widget, which normally end up attracting the debunkers in droves. So normally, we shy away from making superlative claims about a project, no matter how they bill themselves. But we’re comfortable that this is the world’s smallest Tesla, at least if we have to stretch the definition of Tesla a bit.

This clown-car version of the Tesla Model S that [Austin] built is based around a Radio Flyer replica of the electric sedan. The $600 battery-powered original doesn’t deliver exactly the same neck-snapping acceleration of its full-size cousin, so he stripped off the nicely detailed plastic body and put that onto a heavily modified go-cart chassis. The tiny wheelbase left little in the way of legroom, but with the seat mounted far enough back into the wheelie-inducing zone, it was possible for [Austin] to squeeze in. He chose to pay homage to Tesla’s battery pack design and built 16 modules with fourteen 18650 cells in each, a still-substantial battery for such a small vehicle. Hydraulic brakes were also added, a wise decision since the 4800 Watt BLDC is a little snappier than the stock motor, to say the least. The video below shows the build, as well as a dangerous test ride where the speed read 72 at one point; we’re not sure if that’s MPH or km/h, but either way, it’s terrifying. The drifts were pretty sick too.

It seems [Austin] has the need for speed, and for drifting.  We’ve seen his water-cooled electric drift trike before, as well as his ridiculously overpowered crazy cart.

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An EV Motor Controller Home Build

Many of us will have experimented with brushless motors, and some of us will have built our own controllers rather than using an off-the-shelf part. Doing so is a good way to understand their operation, and thus to design better brushless motor powered projects. Few of us will have gone as far as [etischer] though, and embarked upon building our own controller for a 300V 90kW traction motor.

The tricky part of a high power brushless motor controller lies not in the drive but in the high-power switching arrangements. He’s using a bank of IGBTs, and to drive them he’s using a smaller industrial variable frequency drive controller with its own output transistors removed. He takes us through some of the development of the system, including showing him blowing up a set of IGBTs through having too much inductance between transistors and reservoir capacitor, and then to his final design.

This is part of a project VW first converted ten years ago, and as part of a series of videos he’s produced one going through the whole project. It’s a fascinating breakdown of the parts required for an EV conversion, and the teething troubles he’s encountered along the way.

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The Quest To Find A Second Life For Electric Vehicle Batteries

Rechargeable lithium chemistry battery cells found their mass market foothold in the field of personal electronics. The technology has since matured enough to be scaled up (in both physical size and production volume) to electric cars, making long range EVs far more economical than what was possible using earlier batteries. Would the new economics also make battery reuse a profitable business? Eric Lundgren is one of those willing to make a run at it, and [Gizmodo] took a look at his latest venture.

This man is a serial entrepreneur, though his previous business idea was not successful as it involved “reusing” trademarks that were not his to use. Fortunately this new business BigBattery appears to be on far more solid legal footing, disassembling battery packs from retired electric vehicles and repacking cells for other purposes. Typically EV batteries are deemed “worn out” when their capacity drops below a certain percentage (70% is a common bar) but that reduced capacity could still be useful outside of an EV. And when battery packs are retired due to problems elsewhere in the car, or just suffering from a few bad cells, it’s possible to extract units in far better shape.

We’ve been interested in how to make the best use of rechargeable lithium batteries. Ranging from tech notes helping battery reuse, to a comparison of different types, to looking at how their end-of-life recycling will be different from lead-acid batteries. Not to mention countless project wins and fails in between. A recurring theme is the volatility of mistreated or misbehaving batteries. Seeing a number of EV battery packs stacked on pallets and shelves, presumably filled with cells of undetermined quality, fills us with unease. Like the rest of California, Chatsworth is under earthquake risk, and the town was uncomfortably close to some wildfires in 2019. Eric is quick to give assurance that employees are given regular safety training and the facility conforms to all applicable workplace safety rules. But did those rules consider warehouses packed full of high capacity lithium battery cells of unknown quality? We expect that, like the business itself, standards for safety will evolve.

Concerns on safety aside, a successful business here would mean electric vehicles have indeed given battery reuse a profitable economy of scale that tiny little cell phone and laptop batteries could not reach. We are optimistic that Eric and other like-minded people pursuing similar goals can evolve this concept into a bright spot in our otherwise woeful state of e-waste handling.

Students Use Low Tech Hacks On High Tech Parking Enforcer

If you are a college student and you get too many parking fines, you are going to get in trouble. But one school didn’t count on students hacking their high tech parking violation deterrent. Some even got free internet from the devices.

You pay your taxes or — in the case of students — your tuition. But still, the city or university wants you to pay to park your car. In the old days, you’d get your car towed. But the people running the parking lot don’t really like having to share the fees they charge you with a tow truck driver. Many places clamp a device to your tire that makes it impossible to drive. Oklahoma University decided that was too much trouble, also, so they turned to Barnacle. Barnacle is a cheaper alternative to the old parking clamp. In sticks to your windshield so you can’t see to drive. The suction cups have an air pump to keep them secure and a GPS squeals if you move the car with it on there anyway.

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Floating On The Breeze With A Full Size RC Paraglider

For many people the gateway drug to aviation is radio-controlled aircraft, and in [Andre Bandarra]’s case this led to paragliding. Now he has combined the two, turning his full size paragliding wing into an RC aircraft. (Video, embedded below.)

The primary controls of a paraglider are very simple, consisting of two brake lines that connect to the trailing edge of the wing. When a line is pulled, it increased drag on that side of the wing, causing it to turn. [Andre] connected the brake lines to two 3D-printed spools, which are each powered by a large RC servo that he modified for continuous rotation. These are mounted on a slim wooden frame that also holds the battery, RC receiver, an old electronic speed control to step down the battery power, and attachment straps for the wing. Without enough mass, the wing would just get blown around by the lightest of breezes, so [Andre] hooked a cloth bag filled with sand to the frame to act as a counter weight.

On the first test flight the wind was too strong and the sandbag too light, making it impossible to control. The hardest part of the flight is the launch, which requires the help of someone who knows how to fly a paraglider. The second test day had much better success. With only a slight breeze and a heavier sandbag, the contraption flew beautifully, floating slowly across the beach. He admits that there are a number of improvements he can make, but as a proof of concept using parts he had lying around, it was a roaring success.

For paragliding from flat ground, you can always strap a motor to your back, like the open source OpenPPG electric paramotor. For more crazy RC flying contraptions, also keep an eye on guys at [Flite Test].

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