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The updated version of my affordable Commuter e-Bike with 1000W rear hub motor

20.01.2021

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This project appeared primarily due to the growing distance of my trips. Starting my tests with a 250W mid-drive model equipped with a 14Ah 36V battery on city streets, I soon realized that the mileage of 50-60km (30-37miles) on a single charge is not always enough. As a result, while carrying out the out-of-town tests, including the off-road tests, I had to transport the bike to the test site in the back of my GMC Sonoma pickup.

In my opinion, the modern owner of an affordable Commuter e-Bike should have a choice between motors of different powers, as well as several batteries of different, but at the same time, sufficiently high capacity. Today, a 10Ah battery is sufficient only for commuting and short trips, and even then, not in all cases. I redesigned the case for batteries with a voltage of 36 or 48V which allowed increasing the battery capacity not only to 14Ah, but also easily assembling 17.5, 21 and even 24.5Ah batteries. Since I use Samsung 18650 cells with a capacity of 3500mAh for the manufacture of batteries, and the drive controller is built into the rear hub motor itself, the final weight and volume of the battery box is optimal small. Now, depending on the drive power, the distance of my trip can be more than 120km (75miles), which is quite enough for traveling out of town not using the car.

The second reason was the speed of 25km/h (15mph), which in most cases is quite enough in traffic conditions in city traffic, but became boring for me. However, I wanted to get more sensations and drive when riding along out-of-city paths with ups and downs, especially since these are no longer public roads that can be an obstacle for this. I have already had experience operating the Bafang SWX 02 350W rear hub motor on my very first prototype that can gain speed up to 42km/h (26mph) without pedal assistance only with the help of the throttle. Therefore, I wanted to try the 1000W motor and reach a speed of over 60km/h (38mph). It is essential to note that the electronic control of the drive makes it possible to limit the maximum speed on the display not to violate the current speed limits established for e-bikes on public roads.

Similar to my other prototypes, the optimized with CAD simulation patent-pending affordable Commuter e-Bike frame will be produced without welding from durable 6061 and 7075 aluminum alloys using hybrid glue-rivet technology, so the weight will be about 3kg (6.6lbs), and the weight of the electric bike itself will be 20-26kg (44-57lbs), depending on the selected drive unit and battery capacity. I have already covered over 3.3 thousand km (2000miles) on my latest prototype with the 250W mid-drive. At the same time, I always tried to subject it, and therefore the frame, to the maximum possible loads and tests, starting with off-road tests and ending with frequent extreme rides on road curbs of various heights. As I have already mentioned, there was no damage, as well as corrosion, of the frame and its

elements, over the past two years. And this is with my weight of 120kg (260lbs). There was an idea to add a 25kg (55lbs) bag of sand, placing it on the frame, but the first attempt quickly illustrated that this would not be a very convenient solution for pedaling.

Thus, I only need time to get the most objective results of testing my prototype with a 250W mid-drive. Whenever possible, I will gradually “gain” kilometers and share the news with you. As described above, it became a little bit boring for me to ride with a 250W motor. Therefore, I hope that testing of my affordable Commuter e-Bike with a maximum power of 1000W hub motor will not only be an interesting new adventure but will also allow one more stage of tests with increased loads, the results of which I will definitely write about.

In addition, there are plans to select puncture-resistant tires, as my experience with the latest prototype showed that punctures are quite often. I also plan to test various models of production front and rear fenders, LED headlights, and rear racks and choose the most suitable ones. Another challenge for my next trips will be to test the performance of the Tektro braking system with 180mm disc brake rotors in conjunction with a 1000W rear drive.

Baruch Dorfman