Watching the progress in battery and motor technology over the past ten years, I thought we had come a long way. But every time I look back at what they were doing in the late 1800’s I’m amazed at how little we’ve advanced since then. Or rather, how far ahead they were back then. Those bowler hatted bustle wearing Victorians really had it going on.
A college dropout, living in his parents’ basement, in the late 1800’s Andrew Riker began experimenting with electric vehicles, starting with bikes. In 1884, he designed and built an electric three wheeled car using an English Coventry tricycle. It had a 40 volt lead-acid battery bank under the seat, driving a 1 hp motor, with a 25 mile range at a speed of around 25mph.
Basically, the same thing I’ve come up with 150 years later.
In 1888 (there’s that year again) he founded the Riker Electric Motor Company in Brooklyn, NY, and became the largest manufacturer of electric vehicles at the time. One of his production trikes won a race at Providence, Rhode Island, setting a record for the fastest mile in 2:13, with an average speed of 27mph. It was also one of the first uses of electric lights on motor cars instead of traditional kerosene or coal oil lamps – which tended to be somewhat hazardous during collisions.
These are photos of that production model electric trike, from the Henry Ford Museum. Maybe I should upgrade to leather suede seats and brass gauges . . .
Road Test #1 was just a ride around the neighborhood in the dark, just to make sure everything was wired right.
For the first real test, Road Test #2, I took the bike to long valley next to Shenandoah National Park. The flat road runs along a mountain stream and dead-ends at the park. Not only a nice place to ride, but there’s very little traffic.
Mostly I wanted to see what the thing would do. These motors are intended to be used in various levels of “pedal assist” mode. You do some of the work and the motor does the rest. You adjust the level according to how much work you want to do. To get a sense of the power of the motor and the range of the battery, I did this first test on throttle alone – no pedaling.
Here’s what I learned:
• Top speed on flat ground is 40mph.
• Average speed on throttle alone is around 35mph.
• At these speeds you need goggles – not just for bugs. The wind alone made my eyes water until I couldn’t see.
• A grasshopper in the face at 40mph gets your attention.
• Range at this speed, with no pedaling, is over 30 miles on a single charge.
• Potholes are bad.
Hitting a pothole, my taillight bounced off down the road, and I almost lost the battery. I later reworked the battery bracket to make it more secure, and added some straps for good measure, and replaced the tail light with something more effective.
With the stock sprocket that comes with the motor, 25mph is about as fast as you can pedal comfortably. It’s not that it takes much effort – none at all really – you just can’t move your legs faster. That’s also a reasonable average speed on a bike.
Still, with that as the top end I wasn’t really making good use of all the gears. There was so much reserve power there was almost no need to change gears. The stock sprocket is for general purpose use on a conventional bike, where you might do some off road trail riding. I’ll mostly be riding on roads, so speed and efficiency are more important than raw power.
To extend the range, I replaced the stock sprocket with a larger one. So far, that has let me pedal slower at higher speeds. Will have to see how it does on hills and overall range.
From the beginning, the intention was to see how far an electric powered trike could be pushed as alternative transportation. I even drafted a lightweight aerodynamic shell to make it even more efficient, and more practical in bad weather.
Draft 3D Model of Shell Body
Last month I ordered the various components needed to add the electric power.
You can buy the gear direct from manufacturers, most of whom are in China. But but there are a handful of reputable suppliers in the US who deal with the hassle of quality issues, testing the parts before shipping them out, and who provide both technical expertise and support when problems arise. They also navigate the challenges of figuring out which components work well together. With all the variables in watts, amps, voltage, etc. for every component available, from motors to controllers, batteries and chargers, all the parts have to be made to work within a common range or something will fry.
These dealers have emerged as hubs of rapidly changing information, and most participate in active online forums where builders and suppliers exchange info and results, ranging from bulit-from-scratch prototypes to complete production e-bikes delivered ready to ride.
Some motor configurations are best suited for specific applications. A good dealer can cobble together packages of various compatible parts and then sell them at discount if bought together as a package, reducing shipping costs. This discount allows them to offer expertise, but remain competitive over ordering the parts individually from disparate overseas suppliers. Speaking from experience, it’s very nice to have someone on the other end of a transaction who is invested in making your project work.
I configured and ordered a package from Luna Cycle in California, and give them high marks. They actually make their own batteries, which is a big plus. Not only are these high power batteries expensive, but they can be dangerous if not done properly. Flaws in manufacturing make batteries, especially those cheaply made, a frequent point of failure.
When it comes to electric bikes, motors come in two basic designs. After years of trials and testing, the options have come down to hub motors and mid-drive motors.
Hub motors are cheaper to make and easier to install. A hub motor can be ordered pre-built into a spoked wheel, sized to fit your bike. This allows someone with very little mechanical know-how to simply swap out the original wheel that came on a bike for a new motorized one. Plug in a battery and controller, and you can be on the road in an hour or two, tops. The components are weatherproof and reliable. For all this convenience, you give up some power and efficiency, but it’s very easy to do with a bike you already own.
The other option is a mid-drive system. While hub motors simply apply power to turn a wheel, mid-drive motors are installed inline on the frame to apply power to the chain at the front sprocket. These are more troublesome to install. You have to disassemble and remove the pedal drive parts of the bike and replace them with the new electric motor+pedal combination. It requires some specific bike tools. The size of the parts have to be ordered to fit your bike frame, and even then some customization can be required to make it all work.
But, if you have the patience, or just need more power, the advantages of a mid-drive system make the effort worth it. A mid-drive motor adds a tremendous amount of power where the power is designed to be – at the pedals – and the existing gear set on the rear wheel remains intact. That’s the key. The gears become an efficient transmission system so the motor works at optimum efficiency. Gear down as needed to accelerate or climb steep hills. Gear up to maintain speed at the upper end of the range where you don’t need much torque.
I had to use a 6 foot length of pipe for enough leverage to remove the bottom bracket on the trike. It had already started to corrode in place. I also had to machine some parts to make a mount strong enough to hold the battery securely. And had to cold forge a stainless steel bracket into shape to brace the motor, otherwise the tremendous torque it applies could make it spin in the frame.
This project has been in the wings for a while. I just recently started work in earnest, and the results have been really interesting, so am ready to share some details.
I’ve been following advances in small, efficient electric motors and battery technology, particularly when applied to alternative forms of transportation. It’s been a hot topic for the past decade, though mostly among esoteric backyard tinkerers and hobbyists.
Much progress was driven by robotics programs at universities and advanced technology high schools, national engineering competitions, and even the military. Lately it’s been breaking more mainstream, especially in areas like electric bicycles, where there is a large worldwide market to make the economics of mass production both affordable and profitable.
A few years ago I bought a recumbent trike with the idea of using it as a project.
I’ve missed riding a conventional two wheel bike. At my age, the discomfort in neck and wrists and butt took the joy out of it, so I mostly gave it up. A recumbent was a viable alternative that could get me back on the road again, and it’s been great fun as just a human powered bike. Very comfortable – you essentially have a reclining lounger wherever you go. Very fast on flat ground, and it screams going downhill, because the profile is so low there’s far less wind resistance than a conventional bike. And in some ways it’s safer – balance is not an issue, and you don’t have far to fall if you go over.
Added benefit: I could easily strap on a basket so my little buddy could ride along. He loved to ride along.
There are tradeoffs, though. Being so low to the ground means you have less visibility – both to see and be seen. When climbing hills, you can’t stand up on the pedals to use your weight for driving the pedals. It requires all leg muscle. Gearing down works fine – I can climb mountains – but speed over ground is reduced to a crawl. When Terri and I go for rides – she on her two-wheel hybrid mountain bike, and me on the trike – she kicks my butt going up hills. Then I fly past her going down. She’s also more mobile, able to make sharper turns and go off road on rough ground and narrow paths, while I am pretty much confined to smooth wide trails and paved roads.
But, still, I get to ride again. The tradeoffs were anticipated. And a fast trike makes a good platform to experiment with electric power. Though some issues are not easily overcome, like visibility in traffic, adding electric pedal assist will eliminate the hill climbing issue.