Last spring, as soon as I put in the T-17 BB torque sensor, the speed display on the CA went crazy, jumping all over the place. Grin said to install a mechanical speedometer and they have a nice little video showing how to do it.
That's a wierd problem. It sounds like the torque sensor might have a ground that touches the frame of the bike so that it creates either a ground loop, or picks up noise (probably motor noise) on the ground line and feeds that into the CA. I don't understand why that would affect the speed sensor, though, unless it also affects motor operation (because the speed sensor would be one of the motor halls, so anything that causes erroneous output of that sensor that causes wrong speed readings would also cause the motor controller to get wrong position signals).
Or perhaps there's a wiring fault in that CA's wiring / PCB / etc that shorts the torque sensor's cadence (or torque signal) sensor to the speedometer input signal. (perhaps if the pins are next to each other on the MCU, or routed next to each other somewhere on the PCB, there's a solder bridge?)
Anyhow, it would have to be some interaction between the T-17's design and the motor signal hall that's used for speedometer, *or* the PR's output of that signal.
Problem for me is that the board shakes so badly, the tip of the soldering iron, the solder and the contact never intersect long enough to melt the solder. I managed to do it though and I thought I had done a good job, but the first time I rode the bike, I noticed that I still didn't have a speed display and the CA was getting really hot, really fast. I had to turn off the power and cycle home with no power assist, all uphill. That little incident prompted the need for a new CA3, but this time I discovered the joy of solder sleeves and I've had no issues with speedometers ever since.
I have had to build a little workstation for small repair work that has a magnifier and all the tools to hold stuff for me (the pics don't show everything that's there now, and some stuff has changed)
Camera-magnifier electronics workstation
"Zombified" meaning one that has had it's brain disabled...I suppose lobotomized would apply except that in this case the plan is not to actually *remove* anything from the IMA, just disable the main CPU by holding it in "reset", per this thread...
endless-sphere.com
Towards the end of summer, when I abandoned regen completely and set up the bike for power assist only, any unexpected regen problems disappeared. I just don't like riding that way. I like the idea of speed limits for power assist and regen and apparently the V6 controller can handle that better than the V4 controller. So, I'll try it out this year and report back on my progress.
By "abandoned regen completely" what specificaly do you mean? Disconnected controls or wires for it? Changed settings for it (from what, to what)? Etc?
Figuring out the problem also requires knowing whether you were doing the controlling within the CA, the PR, or both, and what the specific settings were for each, and what experiments were tried (and their results) to fix the issues.
Personally, I don't like the path that Grin has taken with regen by modulating it on a throttle or a brake lever. I find that it's counter intuitive. I only want to remember that pulling the brake lever stops the bike and depressing the throttle makes it go faster.
I happen to agree--no matter how well you train yourself to use the system as it is, the reaction time will be longer to do it this way than to just pull the lever. And for anyone already trained over years to use a brake lever normally the reaction time will be even longer than anyone that never rode any bike of any kind and has never used a brake lever. And in a "panic stop", your brain will revert to the control method it learned first / has used longest / most, most of the time. Since braking reaction time is often critical, then this could be an issue in some situations. (if the switching brake lever still controls a well-set-up mechanical brake, it won't matter, but there are numerous bike builds that use *just regen* on the wheel that lever controls (including my SB Cruiser trike) so that there is no braking occuring until the regen engages at the appropriate strength).
AFAIK they did that because they didn't have a second analog input available, so the only option then was to do what they did (technically they could have given the choice between a torque sensor and variable regen, and used that input for it, but it would have probably been an even less popular choice).
There are a few ways around the design. One is documented here:
this project is for those that don't want to use a throttle to control braking force, and prefer a brake lever (perhaps because it is what you're already used to on a bicycle for braking, and if you've ridden as long as i have, it's so hardwired it could take years to change the reflex action...
endless-sphere.com
It's even easier now, because Xiaomi and others make variable-output brake levers, so all you'd need do to use it with the CA is to add a switch to the brake lever (if it doesn't have one) to trip a relay that switches the CA throttle input between your actual throttle and the variable lever output.
If you prefer, you can setup the PR itself to accept the variable lever input directly on a second analog input, and not run that lever to the CA. On older versions than v6 it would be easier because you just separate the throttle and brake wires, and setup the appropriate voltage ranges in the setup software for each to respond to the independent throttles. In v6 you have to change a setting to enable separate inputs first; I think this is on page 20? of the PR manual.
I haven't done this as my source-switching setup works and these days I prefer to not break working things to do experiments, at least on my daily ride.
(am building a new one slowly that will be a new testbed)
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