A month ago General Motors announced plans to wind down production of several under-performers. At the forefront of news coverage on this are the consequences facing factories making those cars, and the people who work there. The human factor associated with the closing of these plants is real. But there is also another milestone marked by the cancellation of the Volt. Here at Hackaday, we choose to memorialize the soon-to-be-departed Chevrolet Volt. An obituary buried in corporate euphemisms is a whimper of an end for what was once their technological flagship car of the future.
We’re all familiar with hybrid gas-electric cars these days, but how about a hybrid scooter that uses supercapacitors instead of batteries? Our hats are off to [Alex] from Labs Bell for the almost entirely-DIY conversion.
The hybrid idea is to drive the vehicle’s wheels with electric motors, but generate the electricity with a normal gasoline engine. This allows the hybrid to control the engine speed almost independently of the wheel motors’ demand for power, allowing the gas engine to run at its most efficient speed and charge up batteries with the extra energy. As an extra bonus, many hybrids also use regenerative braking to recoup some of the energy normally wasted as heat in your brake pads.
[Alex]’s hybrid scooter does all of the above and more. Since the stock vehicle is a 50cc scooter, any increase in acceleration is doubtless welcome. We’d love to see the scooter starting from stop with a full charge. Using supercapacitors as storage instead of batteries is a win for charging efficiency. In urban stop-and-go traffic, the natural habitat of the 50cc scooter, the regenerative braking should help further with gas consumption.
What’s most impressive to us is the completely DIY hybrid control unit that takes some simple inputs (wheel speed and throttle position) and controls regenerative braking, the gas engine’s throttle, etc. Since the hybrid control system is currently under development, there’s even a button to switch between different trial algorithms on the fly. Very cool!
Oh yeah, and [Alex] points out the fire extinguisher on-board. He had occasion to use it for his hybrid motorcycle V1. Safety first!
Any time we hear from [Charles Z. Guan], we know it’s going to be a good feature. When he’s linking us to a blog post with phrases like “If you touch the wrong spots, you will commit suicide instantly”, we know it will be a really good feature. [Charles] is no stranger to Hackaday – we’ve featured his GoKarts, Quadcopters, and scooters before. He was even generous enough to let a couple of Hackaday writers test drive ChibiKart around Maker Faire New York last year.
This time around, [Charles] is working on a power system for chibi-Mikuvan, his proposed entry of the Power Racing Series. He’s decided to go with a used battery from a hybrid vehicle. As these vehicles get older, the batteries are finally becoming available on the used market. [Charles] was able to pick up a 2010 Ford Fusion NiMh battery for only $300. These are not small batteries. At 20” wide by 48” long, and weighing in at 150 pounds, you’ll need 2 or 3 people to move one. They also pack quite a punch: 2.1kWh at 275V. It can’t be understated, taking apart batteries such as these gives access to un-fused lethal voltages. Electrocution, arcs, vaporized metal, fire, and worse are all possibilities. If you do decide to work with an EV or hybrid battery, don’t say we (and [Charles]) didn’t warn you.
As [Charles] began taking apart the battery, he found it was one of the most well thought out designs he’d ever seen. From the battery management computers to the hydrogen filled contactors, to the cooling fan controller, everything was easy to work on. The trick to disassembly was to pull the last module out first. Since all the modules are wired in series, removing the last module effectively splits the pack in half, making it much safer to work on. The battery itself is comprised of 28 modules. Each module contains two 4.8V strings of “D” cell sized NiMh batteries. The battery’s capacity rating is 8000 mAh, and [Charles] found they still took a full charge. Since he doesn’t need the pack just yet, [Charles] removed the final bus bars, rendering it relatively safe. Now that he has a power source, we’re waiting to see [Charles’] next stop on the road to chibi-Mikuvan.