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I've been looking online for explanations of PWM current control. Although I haven't found anything e-bike specific, I keep coming across graphs like Fig 2 of the Wikipedia article "Pulse-width Modulation": Figure 2 "The simplest way to generate a PWM signal is the inter-sective method...

Interesting graph... Since the current is constant for each power level, regardless of speed/back emf variations, the controller must be compensating by increasing the pulse widths to maintain a constant current. Once speed/back emf have increased to the point where current is being supplied...

Looks a useful web site. Unfortunately they are out of 1x spiders atm, but I'm not in a hurry and can wait.

I have a similar problem: I have a Haibike Trekking 6 i630 (2022 model) with Yamaha PW-ST motor and 38T chain-ring. The chain-ring is dished and all in one piece; it slides straight onto the motor shaft - no separate spider. The chain-line appears to be 52mm, and the OLD is 148mm. I would like...

Does the amended graph below represent the lower (blue) power levels better with current eventually being limited by back emf only, due to the controller being unable to supply any more current? I'm not sure why the first red segment (level 5) is sloping. If, in the highest power level 5 , the...

Thanks for the graph. Visual information is always good. I understand the concept of ramping and it's depiction in the graph. When I start off in level 1 or 2, I think can feel the motor ramp up for a couple of seconds (with C14 = 2). It's hard to say if this effect changes when C14 is changed...

I've ridden the bike a bit more and, from watching the wattage on the display, it does seem that C14 adjusts the spread, and possibly spacing, of the power levels. For example: In level 1 C14=1 gave around 25-30W and C14=2 gave around 60-80W. Likewise, level 2 gave around 90W and 130W. The...

I've no idea what the problem might be, but I would check the following (with apologies for stating the obvious) just in case: 1. Is the motor cable plug fully inserted, right up to the line? 2. Is the wheel size set correctly? 3. Is C2 set correctly? My motor runs fine on C2=0, all other...

The torque is fairly strong. Definitely not a weedy motor. The bike maintains 25kph in level 2 in neutral conditions (flat, no wind). I've yet to try it up really steep hills but have noticed the motor feels happier if you keep the speed up by increasing the power level. I've only needed level 3...

Thanks for the suggestions, everybody. Definitely, I'll keep that firmly in mind. That's probably the ideal approach, and it doesn't necessarily have to be a road bike. Before going down that road, I investigated this bike further. Always worth listening to Saneagle :) The Aikema website...

Here's how I got on: I set the max speed to 25kph. I tried P1=88 and the bike cut out at around 9 mph. I tried P1=163 and it seemed to cut out just right at about 15 -16 mph, with strong torque at lower speeds. Later, with the wheel off the ground, I found the maximum no-load speed was 15.8...

Unfortunately the forks are alloy.

Hi Everybody, I've been looking at a road bike conversion, but this doesn't seem as straightforward as one might think. My daughter has a Trek Lexa road bike, XS frame size. Thinking that it would help her up the steeper hills around Goudhurst in rural Kent, my son-in-law bought her a...

Update: I'm coming to the conclusion that either: That's just the way it is. The motor seems significantly stronger than it did with the JYT speed controller, which may have had a lower current limit - no way of knowing. (Label on JYT says 15A max, 8A rated, but programmed max current could be...

PS With max speed set to 25kph (P1 =163, i.e. 8.15 x 20), the no-load speed is 15.8mph.

Thanks Roger. So that's not an issue in the context above. Good to know. :)

Max. no-load speed, level 5 = 18.9mph = 30.4kph. ( I tried C2 = 0 and C2 = 4 with exactly the same results.) Battery voltage 39.8V (Digital voltmeter. Assumed no significant voltage drop due to negligible current.) Max speed normalised to 36V: 30.4 x 36/39.8 = 27.5 kph or 27,500 m/hr...

PS Any idea what the mystery setting C15 is? Thanks.

Interesting. I saw a set of spare idler gears for 95RX on AliExpress yesterday and they were 18/40 teeth, same as mine are. For an older version 95 perhaps? Mine was supplied a year ago. Yose quoted 4.4, consistent with what you have found. I counted the gear teeth, which suggested 8.15*...

Yes, it's a sensored motor. Aikema 95RX. Reduction 8:1 on 700c. The controller KT 17A SVPRD was sold as a sine wave model for which I think Hall sensors are necessary to work properly? If however he motor is working in unsensored mode for any reason, would that mean it is using square wave...