It feels windy all of the time at 25 MPH
I don’t use this bike much preferring instead to ride my Jeep E-bike with it’s little 250W Bafang. With that bike I pedal continuously and with moderate to heavy effort so I get a lot of exercise at a pace I probably couldn’t match even in my youth on a road bike. It’s a lot of fun. This Mongoose is a different animal and it’s closer to what the majority of folks on this board build for themselves and even weak by many poster’s standards. It’s sorta fun too but in a different way. But like I said it’s not getting much use.
I originally built this bike just for the heck of it…and to perhaps use to commute to work. Unfortunately I start early, getting up before the sun, and I’m not inclined to rise even earlier to ride the bike to work. So now on weekends I generally go out for a long ride on my Jeep bike then after charging the battery I sometimes go for a shorter spin on the Mongoose. Since I use higher power with this bike and don’t pedal much I use about 40% more juice with this bike than the Jeep for the same average trip speed. That limits my range using a 12S 8Ah LiPo pack. It also limits my speed and I’ve been keeping it under 20 MPH so I can comfortably make a favorite 17.5 mile loop.
Today I wanted to see what it was like to ride this bike like a scooter with virtually no pedaling at speeds averaging 25 MPH. Again that may be sedate by some folk’s standards but it’s far above my normal ~18 MPH average trip speed. The ebike.ca simulator says the BPM should consume 30 Wh/mi at 25.0 MPH therefore I would need 525 Wh total to complete the 17.5 mile loop. For the ride I combined two 12S LiPo packs, an 8Ah and a 5Ah, to give me a maximum of about 580 Wh. Just last week I rode with the combined packs on the Jeep and consumed them completely on a 52 mile trek using 575 Wh.
Averaging 25 MPH turned out to be a bit harder than I figured. I used the cruise feature to hold the bike close to 25 but of course hills and slowing for stops impacts the average speed. I pedaled only up grades to keep the speed up but in the end I averaged 24.2 MPH over the 17.5 mile course. At 14 miles the motor felt slower as the battery weakened. At the end of the ride though any fear I had about running out of power proved to be unfounded as the wattmeter said I used just 424 Wh of power, which coincidentally calculates to 24.2 Wh/mile. The motor felt cooler than on slower rides though I attribute that mainly to the low 70’s temperatures. The controller too was barely warm, but then I’ve never had a controller get hot on me.
In the end the bike does what it was built to do. The 27.5A controller, 1,300W peak power and the torquey nature of the BPM geared motor means the bike can indeed be ridden like a scooter. Still, for cycling fun I’ll stay with a little motor on a bike that’s enjoyable to pedal.