greenstage killacycle morgen_e_peck transportation tumanako zero_s
Linux for Your Electric Car: Techies Create Open Source EVs

By Morgen E. Peck

Zero is the Apple of electric motorcycles. The Santa Cruz, Calif.,-based company’s bikes coast out of the factory in gleaming perfection with control software that has been optimized for safety and performance. And, as with iPhones, the source code remains a company secret. Gearheads who like to know every detail of how their machines work or want to modify them either have to jailbreak their devices or start from scratch. They can turn to outside sources but, again, the only option is to buy a motor controller kit from a company that has made all of the configuration decisions in advance.

“People who are into electric vehicles like to be able to tweak them to make them faster and to be able to fix them themselves,” says Philip Court, the director of Greenstage, an electric racecar developer in New Zealand.


The Zero S: A beautiful, untweakable machine. Courtesy Zero Motorcycles

So Court is seeking to do for electric vehicles what Linus Torvalds, the founder of the open source operating system Linux, did for personal computers – that is, free them for tinkerers. Court manages an open source project called Tumanako, which means “hope and togetherness” in Maori, the language of New Zealand’s aboriginals. According to Court, it will enable fast motorcycles to go even faster. But it could also be used to build any type of electric vehicle, from cars and submarines to motor-launched aerial gliders.

The main offering of the Tumanako project is a drive package and inverter for a 200kW induction motor. This includes all of the software necessary to take a “go” command from a driver and the calculations for how much power to feed to the motor. Court says his code works but will not be fully open source — meaning there are still snippets of proprietary code — for another 6 months to a year.

They are also working on a battery management system, which charges the Lithium ion cells in the vehicle, while monitoring the load on each one. And then there’s the hardware. Greenstage has designed its own control board and integrated charger to run the system.

Super techies could use Tumanako to fine tune personal creations or modify the vehicle to operate in multiple modes. “If you’ve got a high powered electric vehicle and your son’s recently learned to drive… and he wants to take his girlfriend to dinner, you wouldn’t leave it on the high powered mode,” says Court.

The possibilities for fully customizable electric vehicles are dizzying. With the electric vehicle racing scene growing larger, the hope for an open source motor controller has caught the attention of professional riders like Bill Dube, whose electric motorcycle, the KillaCycle, was was the fastest electrical vehicle in the worlduntil 2010.

Dube, who currently uses a Zilla controller from Cafe Electric, has said he sees “awesome” possibilities in Tumanako. With commercially available controllers, he says, “the software keeps the current, voltage, temperatures, torque, and speed all within very conservative bounds to avoid even a slight risk of over-stressing a component. In racing, you need the system to push all those parameters to the limits. You only need the system to survive until just past the finish line,” he says.

“Controller manufacturers guard their software jealously because they have a huge investment in time and money into the development and testing of that software,” he continues. But that doesn’t mean they always come up with the best solutions for racers. “Open-source controller software is the only way for a typical EV racer to ‘tinker’ with the drive system in a meaningful way.”

Of course, not everyone has what it takes to fiddle with the brains inside their machines.

“It’s a bit of a niche market,” says Court.

There are also safety worries. Bill Mills, an automotive enthusiast in Florida, built his own electric motorcycle from the stripped down frame of a Kawasaki Ninja 250. He opted for a standard, rather than open-source, DC motor controller and battery management system and says he would do so again, partly because he knows that the software has passed through rigorous safety testing. “That’s a concern with battery management systems,” he says. “Where can you show a track record of safety?”

But Court insists that open source projects may actually offer even more solid testing. Not only will Tumanako pass through certification from the Motor Industry Software Reliability Association, it will be vetted by its peers. “With open source… you can’t write rubbish code,” says Court. “Well, you can. But if you do everyone knows about it.”

This kind of transparency is at the heart of the project. Tumanako means hope and togetherness, but on the road, it could mean awesomeness.

Top image: The Greenstage GS750V. Courtesy Greenstage

Morgen E. Peck is a contributor to IEEE Spectrum, Innovation News Daily and Scientific American. Her last article for Txchnologist looked at the challenges of building a house on Mars.

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