elbiot said:
I meant to ask for clarification on "cruise control" and ask about efficiency seeking controllers in that post. If anyone knows anything... A quick google did not give a product.
This subject is a little hard to grasp, I think. Effeciency can mean more than one thing. If you mean nothing more than using the least amount of power concerning your electric bicycle components, then I may be able to help explain.
Higher temperatures are going to reduce efficiency. What is most likely to increase the temperature of things like your motor and controller involve 'high' (relative to their capacity) power output. It is more effecient, and things will stay cooler, if you accelerate more slowly. The way to achieve this is fairly simple, you set a watt/amp/power limit up. The way I choose set a power limit is through a cycle analyst. The power limit I set, that works for me, is in tune with an ideal top speed. Configuring this can be a little complicated, and I doubt I would really understand precisely how you could get there as we don't know what components you will use and I have no clue how this would be accomplished with something other than a throttle. But I am fairly confident that what will help you get to where you are going is focusing on the idea of setting up a power limit. Either a cycle analyst or a programmable controller are the routes I would suggest looking into. The cycle analyst would probably be the best all around here for this.
There is more to this subject, relating to a 3 speed switch (at least that is how I do it). But I am not sure how this would translate into your goals. How a three speed switch works is, you program a controller so that each speed turns the maximum level of the throttle into a different percentage, so if you set (this is a setting you can modify in a controller, which is kind of a complicated process) speed 1 to be 50% maximum throttle, that would mean if you had the throttle half way turned, you would only actually be at 25% throttle and having the throttle fully turned would only turn the throttle to 50% instead of truly 100%. This is useful in at least two situations. I won't go into the first one, but the second one means that if you find what level of throttle is suitable at a voltage to an ideal speed, you can set one of the throttle speeds to basically be sort of like what you are trying to achieve. Lets say we know that at 71% throttle at 52v my bike will be shooting for 20mph and that after that the power output will begin to ramp down and attempt to maintain that speed (RPM), I can then program that throttle percentage to one of the speeds (in the controller settings) and use that sort of like cruise control.
Combining a low maximum power (I use 300w and it serves me perfectly fine, I've ran with less and that was just fine as well for the most part) and setting up the three speed switch appropriately, I can run my bike in a way that is extremely efficient with no room for error. This is sort of like cruise control. I tried cruise control and I feel like it's far less than ideal, cruise control is easy enough to activate for that moment, but it's hard to get like the way I just described (impossible in the idea of genuine power restriction).
Not to bash anyone, but there are plenty of hot rodders on this forum who like to really pump out the power, having little concern for things like range or the ability to meaningfully pedal the bicycle still. It sounds like you really value being able to pedal plenty, so maybe the pedal assist level will work out for you, but what I described with a cycle analyst will allow you to setup a low power limit that is very easy to setup and change to how you like it. If you want 200w instead or whatever, that can easily be done with a cycle analyst. I think you will really value the ability to set a power limit to your liking.
I am sure there are other ways to achieve what I am suggesting, but this is what has worked for me so far.
