KaiYeena
🧲 New user
Hi All, looking for recommendations for a compact and light geared hub motor for a standard MTB dropout 29" rear wheel.
Have a bit of a weird config in mind, for context in the past I had the standard DIY Missile setup of a ~"3kW" (peaked around 7kW) DD hub, 72V 17Ah pack (Molicel P42A's) and big 100A square wave controller. Thing was a missile, sketchy as hell and quite loud, also rode pretty rough as it was a hardtail and the unsprung mass of the huge DD motor made it as smooth as a bag of rocks.
Im in sydney, and my area has a bit of an epidemic of teenagers and kids riding like dickheads on electric fatbikes, surrons, DIY missiles and other things which has brought a lot of public and police attention to eBikes, and i've since analogue'd the bike again (mainly because it didnt ride very well, but also because im an adult with a drivers license and here, the penalty for riding a illegal e-moto is they suspend your license, and I cant risk that).
Sold the motor, however still have the battery, which was quite expensive, and have been looking about converting it again but to a more tame "grandma friendly" setup that will fly under the radar a bit more.
The question then is, can anyone recommend a geared hub that has a very slow wind, or very short gearing, that puts the peak power speed somewhere around the 35-40~kph mark. All of the small geared hubs i've found are clearly designed for smaller wheel, lower voltage systems in mind and when I run the numbers for a 29" wheel at 72, puts the unloaded motor speed like, >80kmh, which if the motor/controller combo is power limited to like 35-40, isnt technically a problem, it'd just behave like a lower voltage pack but without the power loss as the SoC goes down due to the voltage headroom, I just know the switching losses in the controller wouldnt be ideal, and it could probably be more efficient if the speed range of the motor and voltage of the pack were matched better.
The idea for keeping the battery instead of getting a generic 36V downtube pack is to keep the efficiency advantages of the higher pack voltage, also because used it is worth like half what I paid for it and i dont want to sell it at a massive loss only to buy a smaller, worse pack. Also at sensible speeds i'd presumably get amazing range out of it, That is provided I had a motor and controller which could operate efficiently with this setup, which is where I need the help for. Also if anyone has any related controller recommendations i'd appreciate, otherwise probably going to go with a 855/Phaserunner.
Cheers.
Have a bit of a weird config in mind, for context in the past I had the standard DIY Missile setup of a ~"3kW" (peaked around 7kW) DD hub, 72V 17Ah pack (Molicel P42A's) and big 100A square wave controller. Thing was a missile, sketchy as hell and quite loud, also rode pretty rough as it was a hardtail and the unsprung mass of the huge DD motor made it as smooth as a bag of rocks.
Im in sydney, and my area has a bit of an epidemic of teenagers and kids riding like dickheads on electric fatbikes, surrons, DIY missiles and other things which has brought a lot of public and police attention to eBikes, and i've since analogue'd the bike again (mainly because it didnt ride very well, but also because im an adult with a drivers license and here, the penalty for riding a illegal e-moto is they suspend your license, and I cant risk that).
Sold the motor, however still have the battery, which was quite expensive, and have been looking about converting it again but to a more tame "grandma friendly" setup that will fly under the radar a bit more.
The question then is, can anyone recommend a geared hub that has a very slow wind, or very short gearing, that puts the peak power speed somewhere around the 35-40~kph mark. All of the small geared hubs i've found are clearly designed for smaller wheel, lower voltage systems in mind and when I run the numbers for a 29" wheel at 72, puts the unloaded motor speed like, >80kmh, which if the motor/controller combo is power limited to like 35-40, isnt technically a problem, it'd just behave like a lower voltage pack but without the power loss as the SoC goes down due to the voltage headroom, I just know the switching losses in the controller wouldnt be ideal, and it could probably be more efficient if the speed range of the motor and voltage of the pack were matched better.
The idea for keeping the battery instead of getting a generic 36V downtube pack is to keep the efficiency advantages of the higher pack voltage, also because used it is worth like half what I paid for it and i dont want to sell it at a massive loss only to buy a smaller, worse pack. Also at sensible speeds i'd presumably get amazing range out of it, That is provided I had a motor and controller which could operate efficiently with this setup, which is where I need the help for. Also if anyone has any related controller recommendations i'd appreciate, otherwise probably going to go with a 855/Phaserunner.
Cheers.
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