Hill climbers

[jac]

hi just been looking on extra energy web site and saw advert for 65 nm torque motor i would think this should get up most hills but no idea of speed

jim

 

[pwylie]

Phil, I have a Heinzmann hub fitted to a 28" wheel hybrid, the 1122 version.

It stops assisting me at around 15.5 miles per hour acording to the speedo - I pedal faster without power, when not feeling lazy, on the flat. However it barely drops speed when on the hills I come across - somewhere around 12/13 mph.

I have never tried another bike so I can make no comparision but it does go up hills well.

Very expensive however.

I should add that I weight about 90kg.

 

[pictsidhe]

Sakura/powabyke current

I have just got a sakura s200, it has a rear hub motor that is looks to be the same as powabyke brushed front ones, though only a 20" wheel, it has the same Z in a circle. I popped the controller on a test ride (hill abuse test fail), it is 18A, what current do powabyke/sakura brushed motors survive reliably? I have some big hills around here to haul my 100kg up and was thinking of adding a 2nd motor to the front wheel, but it looks like more peak current to the rear one may do the job? I'm going to lash up a stationary torque test with a bench power supply soon but would really like to know what the limits of the motor are before rebuilding/replacing the controller.

 

[pictsidhe]

I measured the thrust earlier, my hi-tech test equipment constited of a stick tied onto the back wheel pushing down on my kitchen scales, 10A multimeter and an old school lab power supply, this is probably accurate to 10%. It was very close to 5N per amp up to the psu limit of 8A, max torque is 22.5Nm at the fitted controllers limit of 18A, resistance was 0.38ohm if my cheapo 2nd meter is accurate. Powabyke motors have a slower wind, extrapolating from mine they should give around 7N per amp, I'll test one next.
To haul me and bike up a 1:7 hill, I need 200N, 40A is probably pushing my luck with the brushes, I'll probably try powabyke innards in my sakura rear hub, 30A and more voltage to get the speed back. It should crawl up a 1:7 at about 5mph, which is somewhat faster and far easier than walking, more tests soon.