New folding project - 20 inch wheel speed

[jusmat01]

Hi,

Last year I made a successful hybrid based on an Akm100 motor on a 700c wheel, KT 06 controller and LCD4. All fine. Power bleeds off at about 27km/h as expected.

I now want to go for a 20inch folding project, with a spare AKM 100 motor I ordered last year. On my last project when I reprogram the LCD4 with a smaller wheel size, I dont seem to get more RPM to get same speed, and I realised that if the wheel size reprogramming worked, it would be a standard speed hack. So......how does this work? Are these types of kit actually suitable for a 20inch build????? I have not purchased a controller or display yet, so am happy to pick alternatives if that works.

Thanks for thoughts.

 

[Nealh]

For smaller wheels one needs a slightly faster motor rpm winding, which rpm akm did you buy. Ideally you want the 328rpm model. If you have say the 260rpm motor then use a 48v battery to make the motor rpm increase 33%.

 

[jusmat01]

Thanks.
does that mean if i had a 328rpm motor then I could have increased speed by down sizing the wheel setting ? That is disappointing I may have the wrong motor for the job then…. Rpm is listed is 201 so 33% uplift does not get me to 328.
Can I safely put 48 v into 36v rated motor?
Thanks

 

[Nealh]

201 rpm is too slow for a 20" wheel, it might make 11.5mph no load speed on the road tho will be like 8mph.
Even with a 48v battery you will only increase to 265 rpm or 15.5mph no load speed and about 12mph on the road.

One can safely overvolt the hub though usually one cuts the max current required.