Lurked here for a while. I bought an old K75RT to convert to an ev. I bought a QS 138 90h to pair with a Votol 200-2SP. Should I upsize the powertrain? This bike is going to be used entirely on road, and the ballpark weight I've estimated will be ~ 600lbs sans rider.
First time build - BMW K75
- Thread starter MuuHD
- Start date
harrisonpatm
10 kW
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- Aug 8, 2022
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Depends on your speed requirements, but 600 pounds is going to be on the heavy end for what the qs138 can move. I'd get something bigger if I were you
I figured as much, I'll take a look at the QS 180 with an appropriate fardriver instead.
Things to consider:
What speed do you want to go?
Are there hills or slopes of any kind?
Wind?
Desired acceleration rate?
All of those and the weight will combine to take a certain amount of power. The motor has to be able to produce that power at the wheel, and the controller has to produce more power than that to overcome the inefficiencies of it and the motor, and the battery has to produce all that power plus more to account for their inefficiencies, and continue to do so for the range you want out of the system.
You can use simulators / calculators like those at ebikes.ca to guesstimate your power needs, before purchasing anything, not just to see how powerful a motor and controller you need, but also to see if you can even fit enough battery on the bike to do what you want (or if you can afford it).
What speed do you want to go?
Are there hills or slopes of any kind?
Wind?
Desired acceleration rate?
All of those and the weight will combine to take a certain amount of power. The motor has to be able to produce that power at the wheel, and the controller has to produce more power than that to overcome the inefficiencies of it and the motor, and the battery has to produce all that power plus more to account for their inefficiencies, and continue to do so for the range you want out of the system.
You can use simulators / calculators like those at ebikes.ca to guesstimate your power needs, before purchasing anything, not just to see how powerful a motor and controller you need, but also to see if you can even fit enough battery on the bike to do what you want (or if you can afford it).
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