Transportation Hacks

1500 Articles

An EV Motor Controller Home Build

February 5, 2020 by 18 Comments

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

February 1, 2020 by 49 Comments

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

January 24, 2020 by 143 Comments

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

January 23, 2020 by 12 Comments

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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How Efficient Can An Airplane Be? The Celera 500L Sets To Find Out

January 22, 2020 by 83 Comments

One of the current hype trends is the supposedly imminent revolution in air transport. So many companies showing digital renderings and mockups to illustrate their own utopic vision for the future, reaching fevered pitch at events like CES 2020. But aviation has a long history of machinery that turned out to be impractical. Wouldn’t it be great if a company focused their resources on building real aircraft and get real data before cranking up their hype machine? The people at Otto Aviation thought so, and their Celera 500L has reportedly taken to the skies.

If you said “Otto who?” you are not alone. The company has zero PR activity to speak of. Limited internet attention started from aviation fans spotting the Celera 500L under construction at its Southern California airfield. Its unusual exterior appearance and proximity to Hollywood made some dismiss it at first as a movie prop. Anyone with a passing interest in aerospace engineering could immediately see aerodynamics was a priority in this design, its long thin unswept glider-like wings implies the goal is fuel efficiency rather than speed. This was confirmed by internet sleuths uncovering patents filed by people associated with the company.

The patents include very lofty fuel efficiency goals, and industry veterans are skeptical. Fuel is a huge factor in aircraft operating costs where small increases in efficiency translate to big dollars over a plane’s lifetime. It’s hard to believe every other plane maker would deliberately leave so much on the table. There must be far more to the 500L inside that teardrop shaped body, with innovations and potentially making some trade-offs no other company has made. We can see two of them from the outside: the 500L traded off some pilot visibility for aerodynamics, and it has very little ground clearance to absorb the impact of less-than-ideal landings.

It’s certainly possible the ideas leading to this plane will fail to pan out in reality like so many ideas before them. Aerospace engineering is a field littered with debris of concepts that looked great on paper but crashed against a hard and unforgiving reality. But at least Otto Aviation is trying something new by building real hardware to get real data, something well worth recognizing in a sea of hyped up fantasy renderings.

[Photo via SoCal Airshow Review]

Electric Unicorn Is Our Kind Of Rideable

January 20, 2020 by 8 Comments

When [Charlyn] took a unicorn rocking horse in to work, it was an instant hit. Naturally, the people wanted more, and suggested it needed electric propulsion. Naturally, she rose to the challenge, and Rocky the Unicorn got a motorized upgrade.

The build consists of a frame built out of PVC pipes, hooked up with Formufit fittings. These are a great way to build useful structures out of PVC pipe, and made the build a cinch. The frame has a footrests for the rider, and the rocking horse already has a comfortable seat. For propulsion, a hoverboard is installed in the base, with the frame sporting a pair of casters to avoid tip over. Twin PVC handles are used to interface with the footplate of the hoverboard, allowing the user to drive and steer, as well as turn on the spot. A bouquet of fake flowers round out the aesthetic and hide some of the zipties.

It goes to show that PVC pipe can be an excellent material for quick, fun projects – all you need is the right fittings to make it all happen! It’s also fun to see a hoverboard used in such a way that doesn’t end with severe injuries.  Unicorns always bring a nice flair to a project, too. Video after the break.

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DIY Lambo That Made The Real Lamborghini Take Notice

January 18, 2020 by 33 Comments

When you start sharing your projects with the world, you never know who might take notice. [Sterling Backus] and his son [Xander] have been building a functional Lamborghini Aventador look alike in their garage, and the real Lamborghini company caught wind of it and decided to turn it into an awesome Christmas ad.

Named the AXAS Interceptor by its creators, the car is built from scratch around a custom tubular space frame chassis. Most of the body panels are 3D printed and then skinned with carbon fibre, with a few sheet metal panels mixed in. The interior is mix of parts from other cars and aftermarket components, with 3D printing to pull everything together. The drivetrain consists of an engine from a Corvette, a transaxle from a Porsche 996, with the rest of the chassis components being either aftermarket or custom-fabricated pieces.

[Sterling] got an unexpectedcall from Lamborghini, and they arranged to secretly sneak a real Aventador into the garage in the dead of night to surprise the rest of the family, and let them borrow it for a few weeks. Lamborghini got some marketing out of it, which most people would probably agree is a pretty good deal. We would admit that we’re quite envious.

The car is driveable, but still many hours from being complete. [Sterling] admits that he is no car building professional, but we’re impressed by what he has been able to achieve so far with this ambitious project, and we’re looking forward to the finished product.

If you want to get your feet wet with your first project car, here’s how you pick one.

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