pedelec conversion with torque sensor

[gothicsurf]

With a 'ready to ride' ebike conversion from Grin, what is the best setup for a pedelec with a focus on being discrete and easily secured? Essentially I am using a classic road/touring commuter bike with a 250-300w bafang hub motor for modest assist to comfortably haul a 60lb trailer. Plan is to find the right level of assist to make the trailer feel weightless and leave it there for a predictable range per 80% charge. As such a don't need or want any kind of dash, except maybe a throttle/assist level adjust just for emergencies. Not sure if the CA mount allows speedy undocking, but the battery/controller/computer needs a quick dismount.

Going with Grin because I haven't seen any other kits that easily integrate with a true torque (not PAS) sensor. Would be nice if they offered a computer a bit less chunky such as for pedelecs whose data could be referred to off the bike (no major need for data analysis while riding). Also thinking of having two of the smaller shark batteries (~13.5 Ah) to carry one for shorter rides and the other charging or two and involve a swap for longer rides. Maybe others do the same? Any experience here would help --

 

[d8veh]

Torque sensor is an unnecessary and expensive complication for riding on the road. It has advantages for off-road riding.

Cheapo controllers have speed control on the PAS, so you get max power in all levels, which gives an aggressive and uncontrollable start. What you want is a controller with current control ("torque simulation" in Chinese English) that gives a different power for each PAS level. In after-market kits and parts, these are mainly from Kunteng (KT). You can get them from Topbikekit, Elifebike (PSWPower), BMSBAttery and places like that. Always get the LCD3 with it because that one gives the best access to all the settings. Get a sine wave version for hall sensored motors.

 

[docw009]

I had been riding hub motor bikes and one midmotor Bafang BBS02 for two years when I finally got to do some demo rides on mid drive torque sensor bikes at a Chicago bike expo. It was in a parking lot with a track, but they did have a simulated hill to show off the motors. You could get up to a good speed on the circuit nut not for long because it was small..

The pull from a 250W Bosch midmotor is strong, but what good is T/S when you're going uphill in the wrong gear. STomp on the pedals. The motor still stalls and you fall over. At least my wife does. She wasn't impressed. Neither was I. If it were a $25 upgrade, I might like it, but there's better used for $200 in my opinion on a bike ridden on pavement.

Now there are some awful cadence sensor controllers. I had one with the SW900 LCD. It had no finesse at all, All five assist levels took you to max speed,

 

[greenspeed]

If you have a Grin Cycle Analyst V3, you can get a torque-sensor-like effect with a PAS_12P https://www.ebikes.ca/shop/electric-bicycle-parts/torque-sensors/pas-12p.html .



I set the Assist Start Level to 50% Thr and Assist Scale Factor to -3.00% per pedal RPM. That tapers the throttle down as my pedal RPM increases.

 

[HrKlev]

Have you considered the tsdz2? It has torque sensor and you can get it with a really discrete display. If you like to tinker a bit it gets even better with the open source firmware. There are some quality issues of course, but unless you are a really big guy og going a lot offroad I it should be fine.

The lightest.bike kit also gets torque sensing, but its not available until october, so noone knows how it will be.

Kuteng controllers can also be ran with torque sensor if you install open source firmware. Again, it is if you like to tinker a bit.... They can be ran without display I think, or wit a small, discrete one.

I agree with the cycle analyst beeing too clunky, but I think it is the easiest to get up and running. All the customization you can do without messing with serial line adapters, etc is amazing. It would be nice with a new version wit a smaller display, though.... You can not run it without the display, as all the processing of torque sensor signal, throttle, brake signals, etc happens in the same unit as the display. You would have to put it in a triangle bag or something if you dont want it on the bar.

If you are happy with the power level you are at, the Bafang g310/311 looks like a really silent and light motor, coupled with a baserunner, torque sensor and a Cycle Analyst. Its not the cheapest setup, though....

I would never build another pedal bike without a torque sensor myself, so I guess people are just different. I have tried different cadence setups, and I dont like them at all.