Changing wheel diameter setting

Electrically assisted bikes, trikes, etc.
User avatar
philg
Posts: 553
Joined: 7 May 2009, 12:13pm
Location: Porlock, Somerset

Changing wheel diameter setting

Postby philg » 1 Sep 2020, 5:39pm

I do like the Lishui (speed) controller kit that Yosepower are now supplying, and prefer it to the previous KT/LCD3 (current) controller, at least for road bike use. I usually set to PAS 3 (from 5) which corresponds to ~12mph and rarely need to adjust it again, unlike the old current control where I was forever fiddling with it according to the road conditions (YMMV obv.)

It does have a 'feature' though that baffles me. Why, when I set it to the road legal (UK) 25kph, do PAS levels 3,4 & 5 seem identical (at ~15mph) when I would have expected the levels to be a fixed % of the set max speed????

It appears that the speed levels are preset regardless of the user set maximum so instead of 5 levels it has in effect only 3. The Swytch kit uses the same speed control but does correctly give up to 9 different levels as you might expect.

I'm wondering that if I set the wheel diameter to 20" then I'll get the speed levels reduced by 20/28ths? and bring all the settings back to different values, assuming I increase the max speed proportionately as well?

PAS mph 20/28
1 8.7 6.2
2 10.6 7.5
3 12.4 8.9
4 18.6 13.3
5 21.8 15.5


?

hemo
Posts: 850
Joined: 16 Nov 2017, 5:40pm
Location: West Sussex

Re: Changing wheel diameter setting

Postby hemo » 1 Sep 2020, 10:09pm

Speed controllers are harder on batteries as they demand /supply max current all the time much like using a throttle only bike.
The speeds are pre set, it is unusual for someone to prefer speed control over the much nicer current control models.

For flat terrain riding I only ever use PAS1 with my current control controller, using the other PAS levels isn't necessary unless inclines are encountered. With current control max speed can be achieved in each PAS level, the best bit is one gets more range from the battery then speed control.

User avatar
philg
Posts: 553
Joined: 7 May 2009, 12:13pm
Location: Porlock, Somerset

Re: Changing wheel diameter setting

Postby philg » 2 Sep 2020, 7:20am

Speed controllers are harder on batteries as they demand /supply max current all the time much like using a throttle only bike.

That is not how the Lishui or Swytch controllers operate - they are nicely progressive until the set speed is reached. What you describe only happens when the speed is set to the maximum and in that situation both types of controller are the same.

As for being hard on the battery, that is also the opposite of my experience - with the Swytch's relatively small (360Wh) battery I managed 45 miles in Gloucestershire using less than half it's capacity.

For flat terrain riding I only ever use PAS1 with my current control controller, using the other PAS levels isn't necessary unless inclines are encountered. With current control max speed can be achieved in each PAS level, the best bit is one gets more range from the battery then speed control.

I set my speed control to ~12mph so in flat/undulating terrain, where I can usually maintain a higher speed unassisted, the motor is off and uses no current at all. It is far from flat around here so with my current controllers I am constantly resetting the assist levels as the gradients change.

With speed control I rarely touch it for the whole ride, if my speed drops then it gives me more assistance - it's pretty effective.

Any thoughts about the wheel diameter question?

ETA: I've answered my own question by trying it
The 'speed' settings are actually RPM levels, so unless the wheel size is physically changed, then the speed levels will stay the same

Lucky that I don't need 5 levels but it is a bit rubbish not being able to change them - I'll ask Yosepower support who have been quite responsive to previous queries