by The_Toecutter » Thu 21 Jan 2021, 01:27:46
A week ago I finally got my custom designed/built velomobile converted to electric. Having next to no money, I slowly accumulated the parts needed over a 2 year period. Now that I got the last few needed components, it runs as an EV.
It is highly efficient. Without the tail, and with the torque sensor scaling my pedal output to account for 1/3 of the motive force, I only need about 8 watt hours per mile to maintain 30 mph on flat ground. That is the equivalent of more than 4,200 miles per gallon. With only a 46.8V 10.5AH battery pack purchased used for $60 and limited to 1,250W power draw by the controller, it tops out at 46 mph and gets about 60 miles range at 30 mph. I just got the regen braking working today and that should improve the range about 5-10%. Thanks to the electric motor, my rolling averages are comparable to a car in city driving conditions, especially now that I don't have to slog up steep 20% gradients at less than 10 mph in low gear anymore.
It is also able to be pedaled at a decent speed with the motor disabled entirely, including overcoming its cogging losses. Without the tail, I can still sprint to 32 mph and maintain 20 mph on flat ground purely under pedal power. With the tail present before installing the motor, it was significantly faster under pedal-only, but I wasn't lugging a 17 lb hub motor whose cogging losses amount to about 35W at 30 mph, and thus cruising speed was closer to 24-25 mph and top speed about 37 mph. So, there is no range anxiety for this vehicle since with everything shut off it can still be pedaled significantly faster than a normal bicycle, and my low gear is low enough to climb up a steep hill at 3.5 mph at 60 rpm cadence.
In order to mount the motor, I had to remove the tail piece because I didn't have clearance to fit the motor. It will be modified to accommodate this before being replaced. This should noticeably improve the aerodynamic drag and allow it to go farther/faster, and get me closer to the unassisted speeds I could reach before installing the motor, maybe 35 mph in a sprint?
Turn signals, permanent headlights, running lights, brake lights, and 110Vac and 12Vdc charge stations for electronics are in progress.
I have also obtained a kweld spot welder and some secondhand barely/never used Panasonic NCR18650GA cells that are demonstrating nameplate capacity. When I get the bugs worked out for this vehicle as well as finish the remainder of the body(I need to install the wheel fairings I made), I will be making a 72V 21AH 1.5 kWh battery pack capable of about 5 kW peak power, which should in theory allow a 70 mph top speed, 200-250 miles range at 30-35 mph, and acceleration comparable to a car, and will probably do 30 mph on only 6 wh/mi.
I also plan to add solar to it in the future when/if finances permit.
If I end up living on the street again, at least I'll be mobile. I can fit camping gear, tools/parts, spare clothes, and a few days worth of food/water in the trunk space.
This vehicle is a prototype of something I plan to build whenever I get the time/resources to do so. The long-term vision is a vehicle that can function significantly faster than a bicycle purely under human power, but when powered, be used as a one-seater race car. It will weigh under 100 lbs, accelerate like a fast car, maintain highway speeds with mechanical reliability while getting the electric equivalent of thousands of miles per gallon, and be capable of reaching triple digit speeds for brief periods.
The unnecessary felling of a tree, perhaps the old growth of centuries, seems to me a crime little short of murder. ~Thomas Jefferson