the #GrinMAC itself is supposed to be 8.4lb, but with the heavier spokes+rim and tire+tube (still 1.75in but going from kenda kontact to conti tour and a slime heavy-duty tube) The old hub+spokes+rim+tire+tube was 3.3lb, new stuff 12.7 (no cassette on either weight.)
@Karstan iff you're careful not to let it walk out of the dropout on the way back, but how far do I need to go to get plastic deformation? Went to 150, still at 131 😞
@enobacon Oh wow! I never had springback that high. The couple times I did it I think I had to go about about 2x the change I was hoping for (eg stretch 16mm for 8mm change).
@Karstan got a helper to hold the tape across the tops of the boards, not the same spot as with the axle but it was close to 190, might have had threads for that
Interference between the rack afixment screw protrusion and the torque arm being a much larger flat surface than many bikes might assume to fit there. Otherwise looking fine.
@enobacon lol, so much of bike stuff is "this bolt is 1mm too long, I need to add a washer" or "this frame is 3mm to narrow, I need to bend/grind/shave it a little bit"
The chainstay steps down right where the torque arm mount needs to be, and I have smaller hose clamps with the same band. Do you cut those off or tuck the tail into shrink wrap or something?
@Karstan The hose clamps are going to want to pull it over to center on the stay though. This bracket has a bunch of offset in the other direction but I can't use that adjustment. Maybe a longer connector bolt and an aluminum spacer between the arm and the mounting bracket.
@HayiWena the step-down could be aluminum or poly shim maybe, but the alignment is off where the mounting foot basically needs to be an opposite of itself, or I need to put a spacer between the torque arm and mounting foot.
@enobacon Oh boy, I missed the second and third images. If it's steel and you can bend it, I say bend away! Or get better at whittling wood. Which bike is this going on?
@HayiWena The torque arm is aluminum but it's actually nearly aligned with the chainstay, and the mounting foot is just made to offset more in the other direction.
Currently seeking a ~1/4in thick piece of aluminum roughly 5/8 in diameter with a hole in the middle or I can drill it. The best bet for a starting point seems to be a piece of 4ft bar stock for $25 and a bunch of sawing and filing 😞 or somewhere can send me one for $20-50...
For #regenBraking control on grin #CycleAnalyst#eBikes, can you just plug a second throttle in to one of the e-brake connectors? #BikeTooter One throttle for go and one for stop?
@enobacon FWIW I've definitely read mentions of using a throttle as a way to vary braking force, but I dunno if it requires more than just plugging it into the CA. Please share if you try it!
Current status, two nylon washers as a spacer (as placement, not for motorized use) the rest fits but this is the hard way to face the screws of the hose clamps. Rode up the block, no battery, surprisingly little drag (or I'm just a beast)
chain a little close to the battery but what if I put the front chainring on the same side of the crank as the stoker one (🧐) that's 3/8in farther out in the back 🤪
Looking at the #cycleAnalyst and #baserunner settings and #GrinMAC with the bike on the workstand, trying to figure out the #regenBraking#eBikes thing #BikeTooter. From everything I've seen, it should be configured for brake lever + throttle to vary the amount of regen force, but I can't feel any difference while turning the cranks by hand, showing over 5mph on the CA. Should it be perceptible in the work stand, or what am I doing wrong?
Wider rim + different brake levers + no cable slack = never getting new brake pads or something (also the cable stop is on a part of the frame where the cable needs to get even slightly longer to take the slack out of the timing chain 🙃 .)
Still stuck on #regenBraking not working? The brake signal is clearly getting to the controller, I'm checking the settings but not finding clear documentation, and posts about it online are mentioning settings, like regen phase current, that aren't in the app? 😖
Nowhere to export the current settings to a file? (+ values no change after autotune 🐞) Should I be using the linux app instead of the android one (apparently need to do that for the CA app anyway, doing this on a chromebook, hopefully can run it on linux mode...)
I did see -4W on the display when cranking at 15mph and engaging the front brake. I guess it's working and even the nylon spacers seem to be doing fine but I think cutting that chunk of aluminum is my final step before we go ride.
I was able to see the regen and brake lights come on in the dashboard, not seeing 19A regen though, bumping that limit up to 1C seems to be part of it but where is the -1100W reading? I'm not feeling anywhere near that amount of resistance. (What does that 1C charge rate do to a cold battery?)
I guess the resistance is palpable around 20mph, still not seeing any charging indicated beyond ~4W. (Maybe that's a one-hand-cranked power level with about 40% recovery efficiency?)
How much does a bike trainer stand weigh without the resistance bit #BikeTooter? (The kind that holds each end of your axle.) Can I get an axle-mounted kickstand (for 20in wheel) that would hold it up so we could ride it stationary to charge the #eBike? #EVcharging
Rear derailer rubbing the spokes on the motor a bit, 3/4 turn on the low limit, maybe needs the same for high, and a cable adjustment (entire cluster sits a smidge to the right. Regen definitely not showing a lot of stopping power but I only had one car-infested hill to test on
So the problem here was the android app - missing some parameters 😲 but the linux one runs fine on a chromebook with VM so we're off to the races (the stopping races, but I gotta tune down the max regen phase current maybe? The 80A had it coming on like a stick in the spokes, especially with ebrake=.49 and the 0.8-0.0V range mapped for #regenBraking.) #GrinMAC#eBikes
I took it for a short ride with these settings and I'm pretty pleased. My ebrake=0.75V, 40A regen phase current, 12A max regen battery current.
I don't like the brake+throttle modulation scheme though, especially because I think the throttle switches to that much "go" when you let off the brake 😖 . Thinking about how I use it, I would probably just want the brake switch to engage a speed limiter, and if I slow down slightly with mechanical braking (or throttle modulation) limit to that speed.
regen max ~320W coming down the hill at 15mph with both kids on (tandem + trailer bike) which is roughly half of where I have the max charge amps set, maybe need to turn up the max regen phase current to 40A?
big day of successful rides on this, still only getting about 300W max regen (and I have some issues with how to control it). I think everyone in SW Portland except me got a picture of us with the tandem + trailer bike and 2 kids.
topping out at ~22mph down Barbur (seems to be the case whether I'm fully on the throttle or not, modulo maybe 2mph, maybe could go faster with field weakening) cc @Karstan I think you asked elsewhere in this thread.
(no trailerbike attached here, I'm not sure I would ride this fast with both kids on, or even much faster than this with one, without bigger tires and/or suspension.)
I feel like it's #NewBikeDay halfway through this build thread, now that this #BikeFriday#tandem#GrinMAC motor setup is rolling 🚲💨! This morning I took one kid to one school, met our other half after other kid's appt, took that kid to other school, caught back up with other parent and gave her a ride home (without the trailerbike, pic was yesterday pickup for a playdate) and only one seatpost adjustment 🎉
I raised the regen motor current to 80A and still not getting higher than 300W regen, 59V * 12A max regen charge current, should be ~700W, after the motor inefficiency... right?
@tjr I'm having to use the mechanical braking to stop the bike from speeding up, so there's more power there that it's not able to take in. Looked like maybe 320W when I upped it to 13A, so it seems like that is what is limiting it (the battery is 14.5Ah so I'm not sure how much more I can push into it.)
@tjr but those are just settings in the motor controller, I guess I could put a meter on the battery, if I can get it setup where the stoker can read it.
With max charge at 13A, it goes to 330W 🤨 i.e. 13/12ths... And the cycle analyst shows AMin=-8, which would be ~470W at 59V, but still 2/3 of my 13A charge limit... what is this doing? Definitely not going to save much brake pad wear here if it can't take in that 800W or so off my friendly neighborhood hills. #regenBraking#eBikes
The suggestion from GRIN is that I could apparently scale up the regen current setting by 59/25ths, but setting that to 28A does not seem like an ideal solution / does not inspire confidence (how much can I trust the BMS to correctly limit the charge current just-in-case, assuming I manage to first check with a meter that the typical actual current is not over ~12A?) #regenBraking#eBikes
Also, being told there's currently no way to do a dynamic regen clamp speed 😞
@kevinschaper@Andres4NY IIRC, you both have the GMAC motors? What is your max regen amps set to? The cycleAnalyst is typically showing min A=-6, max A=20, (so that matches max going amps) regen voltage is 59V, why is my setting max_regen_amps=12A limiting it to 6A? I want to check a meter to confirm the current (need to enlist a child stoker/assistant), but how do we feel about just setting it to 2x 0.8C / why is the limit setting being mis-applied by 2-2.4x? (based on my experiments)
@Andres4NY@kevinschaper thanks, sorry I thought you had something with regen at one point. Should we make a directory of who is running which motors? 😅
@Karstan though if I compare the video timestamps vs math and measurements on googlemaps it says I was doing 15mph so now I have to wonder how that camera or the map is this far off 😖 I don't think it's the CA speedometer.
edit/update: 21.8mph -- I measured to the first bus stop on the map and marked time to the 2nd 🙃 (had ~1880ft in my calc instead of 2770)
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