Since I'm building my own motor controller, I'm thinking of using something other than just a "throttle" to control its speed. This is based on my experiences with riding a (fairly weak) Wilderness Energy 24V brushed motor: there were actually only a few "use cases" for what I wanted to do, that didn't necessarily map as well to a throttle control as they might to some other way of controlling the bike:
- I'm going slow, I want to go faster, so I push the throttle all the way.
- I'm going fast, and I want to keep going at top speed, so I have to ride a mile holding the throttle down during the whole trip (makes your thumb get tired).
- I'm going a little faster than I want to be going, so I have to feather the throttle to reduce speed gradually.
- I want to pedal, but I want the motor to make it easier. When you're accelerating, with the low power 24V WE motor, that's easy, you just push the throttle all the way in while you pedal. But if you are already going at speed and just want a certain level of assist, it is trickier to get the right amount of assist.
Now, the current bicycle I'm building will instead have two 36V 500 Watt BLDC e-bikekit motors and a 48V battery, but some of these will apply even more: I expect it will be even trickier to maintain just a certain amount of assist when I have that much power at my disposal, and the bicycle will be capable of going faster than I want to run all the time, so holding the throttle in all the time will not work, even if it did not make my hand tired which is the biggest problem I have had.
So, I'm thinking of something that would work more like cruise control on a car, with some added ability to switch to generating a fixed amount of torque instead of fixed speed, and also the ability to use the motors for braking. I have drop bars (the ram's horn shaped things) so it has been tricky to figure out where to place a throttle. I do have a pair of extra gear shift levels attached to the vertical stem below the handlebars; they aren't connected to anything - I put them there to use to control a motor. I'm thinking I could do something like use the lever on the left to set a speed, and the lever on the right to set torque. So for example, if I wanted to accelerate gradually to a high speed, I could set the torque lever low and the speed lever high. Or if I wanted to maintain a medium speed but have the bike work hard to keep that speed even on hills, I could set the speed lever in the middle and the torque lever all the way up. There could be a toggle switch that if I set it one way, the bicycle tries to maintain a fixed speed based on the setting of the speed lever but limited by the torque lever, and in the other position the bicycle gives a fixed amount of pedal assist according to the setting of the torque lever but limited to the speed lever.
I would also have switches on each brake lever to control electric braking. It would work something like this: if I click the rear brake lever, that simply turns off the motors (because you use the rear brake as a drag brake to slow down; this lets the motor resistance drag the bike or at least stops it from accelerating). If I click the front brake lever, this activates regenerative braking (because you use the front brakes to come to a stop at a stop sign or turn). And if I click both at once it would skip the attempt at regenerative braking and just short the motor windings for maximum drag (because hitting both brakes at once means "oh sh*t I need to stop right now"). I could of course squeeze the brakes further to use mechanical braking; these would just be the things that are activated by tapping the brakes far enough to click the button without actually making the brake pads touch.
Finally, I think there should be a way to just tell the controller "maintain the current speed". You'd pedal (with or without assist) up to a certain speed, and then decide that's how fast you want to go and set the speed there. This would be more like how cruise control works on cars. I'm not sure how this interacts with the other controls or what kind of input device to use for this though.
- I'm going slow, I want to go faster, so I push the throttle all the way.
- I'm going fast, and I want to keep going at top speed, so I have to ride a mile holding the throttle down during the whole trip (makes your thumb get tired).
- I'm going a little faster than I want to be going, so I have to feather the throttle to reduce speed gradually.
- I want to pedal, but I want the motor to make it easier. When you're accelerating, with the low power 24V WE motor, that's easy, you just push the throttle all the way in while you pedal. But if you are already going at speed and just want a certain level of assist, it is trickier to get the right amount of assist.
Now, the current bicycle I'm building will instead have two 36V 500 Watt BLDC e-bikekit motors and a 48V battery, but some of these will apply even more: I expect it will be even trickier to maintain just a certain amount of assist when I have that much power at my disposal, and the bicycle will be capable of going faster than I want to run all the time, so holding the throttle in all the time will not work, even if it did not make my hand tired which is the biggest problem I have had.
So, I'm thinking of something that would work more like cruise control on a car, with some added ability to switch to generating a fixed amount of torque instead of fixed speed, and also the ability to use the motors for braking. I have drop bars (the ram's horn shaped things) so it has been tricky to figure out where to place a throttle. I do have a pair of extra gear shift levels attached to the vertical stem below the handlebars; they aren't connected to anything - I put them there to use to control a motor. I'm thinking I could do something like use the lever on the left to set a speed, and the lever on the right to set torque. So for example, if I wanted to accelerate gradually to a high speed, I could set the torque lever low and the speed lever high. Or if I wanted to maintain a medium speed but have the bike work hard to keep that speed even on hills, I could set the speed lever in the middle and the torque lever all the way up. There could be a toggle switch that if I set it one way, the bicycle tries to maintain a fixed speed based on the setting of the speed lever but limited by the torque lever, and in the other position the bicycle gives a fixed amount of pedal assist according to the setting of the torque lever but limited to the speed lever.
I would also have switches on each brake lever to control electric braking. It would work something like this: if I click the rear brake lever, that simply turns off the motors (because you use the rear brake as a drag brake to slow down; this lets the motor resistance drag the bike or at least stops it from accelerating). If I click the front brake lever, this activates regenerative braking (because you use the front brakes to come to a stop at a stop sign or turn). And if I click both at once it would skip the attempt at regenerative braking and just short the motor windings for maximum drag (because hitting both brakes at once means "oh sh*t I need to stop right now"). I could of course squeeze the brakes further to use mechanical braking; these would just be the things that are activated by tapping the brakes far enough to click the button without actually making the brake pads touch.
Finally, I think there should be a way to just tell the controller "maintain the current speed". You'd pedal (with or without assist) up to a certain speed, and then decide that's how fast you want to go and set the speed there. This would be more like how cruise control works on cars. I'm not sure how this interacts with the other controls or what kind of input device to use for this though.
