BMSBattery Torque sensor

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WheezyRider
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Re: BMSBattery Torque sensor

Post by WheezyRider » Feb 10, 2018 2:25 pm

It appears that this thread died out with no input from anyone who has actually used BMSbatteries' Bottom Bracket Torque Sensor System. I am very interested in this kit, but I hate to invest the money with no information from users, so if anyone can shed more information (or knowledgeable opinions) on this product, I would appreciate your advice. Perhaps I have missed other relevant threads?
I am reminded of "How to identify a Pioneer" - he's the guy lying in the dust with arrows in his back!

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motomech
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Re: BMSBattery Torque sensor

Post by motomech » Feb 10, 2018 7:25 pm

Wheezy, I PM'ed you.
I have an extra KT sine wave controller w/ a SLCD-3 display you could try out. If you are looking for the best budget PAS experience, it has 5-level "torque imitation" PAS.
As w/ most of these "off the shelf" ebikes, it could be a little tricky to intergrate.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, Crazy Bobs run ghetto tubeless. 25 mph. Mean Well HLG-320H-54A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 14S LiPoly elifebike 9-FET 20A controller. 23 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

WheezyRider
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Re: BMSBattery Torque sensor

Post by WheezyRider » Feb 12, 2018 11:15 pm

Motomech;

I saw your PM before I saw this reply. I look forward to discussing this further with you, and then sharing any pertinent results on this (or other) thread(s).

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motomech
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Re: BMSBattery Torque sensor

Post by motomech » Feb 13, 2018 12:17 pm

I look forward to discussing this further with you, and then sharing any pertinent results on this (or other) thread(s).
I agree, so lets keep the discussion here.
For those looking for the best(most realistic) PAS experience w/out breaking the bank, should try out one of the newer sine-wave controllers w/ one of their SLCD displays.
Your typical 3-level square-wave controller uses speed (motor RPM) values to limit the set-levels. For example, a mini-motor might have limits of 12 mph, 16 mph and 20 mph, in either cruise or PAS. This works well enough on a low-powered system, but as system power increases, the crudeness of this approach comes to the fore. Imagine a system with a 2 nd. level speed of 20 mph. When the rider stops pedaling, slows down and then re-engages, the motor wants to rush up to that speed level, making for a "jerky" response. Also, as system road speed increases, having only 3 levels can leave "gaps", not leaving the rider the option of setting a speed exactly where he/she wants it to be.
The sine-waves, on the other hand, use Current (Amps) to trigger the PAS levels, making for a more intuitive interface between the rider's input and the motor reaction. It imitates the strain-gauge approach of the higher priced system like the Bionx, hence the name "Torque Imitation" those Chinese engineers have gifted to these systems. And the 5 levels better cover the road speed range.
The first of the sine-waves were offered by BMS Battery several years ago and I tried both the SO6S and the S12S, both w/ the SLCD-5 display. The lilliputian 15 Amp (on a good day) SO6S was under-powered for my Q100 mini motor and the huge S12S was over-kill, but my biggest problem came about because of the odd Voltage of my LiPoly packs. These systems use "Auto-ranging" to read the initial pack value at start-up and that value determines some of the associated parameters. Others have made the LiPoly/sine-wave combo work, but I felt it never was glitch-free.
Recently, the new "KT" sine-waves have been available, mostly from PSW Power (Elifebike), so I thought I would give the "middle of the road" 20 Amp KT controller and LCD-5 display a try;
http://www.pswpower.com/peng/iview.asp? ... 33C0.50CGS
http://www.pswpower.com/peng/pic.asp?Mo ... ID=S220052
But once again, I had some issues w/ the LiPoly and auto-ranging working together and have come to the conclusion that these sine-waves work best w/ the standard 36 V and 48 V Li-Ion batteries.
So after one test ride, I went back to my "tried and true" ELB 9-FET square wave.
Since you need a controller, if you wanted to try this system out, that would be fine(pay me if it works out).
But as I mentioned before, often splicing into a "commercial" ebike can be tricky. If I could see your bike, I probably would have a good idea if it could be done and what it would take to do it.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, Crazy Bobs run ghetto tubeless. 25 mph. Mean Well HLG-320H-54A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 14S LiPoly elifebike 9-FET 20A controller. 23 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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wturber
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Re: BMSBattery Torque sensor

Post by wturber » Feb 13, 2018 6:31 pm

FWIW, I'm using a KT controller (KT48ZWSRLT) that I'm pretty sure is not a sine wave controller and the PAS seems smooth and responsive. The shift to different PAS levels is subtle. You just notice that you are going a bit faster for the same pedal effort/cadence. So I'm not so sure that the good PAS performance is significantly related to whether the controller is of a sine wave type or not.

As an aside, I wonder if the boost converter I use would mitigate the LiPoly voltage issue you had?
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

WheezyRider
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Re: BMSBattery Torque sensor

Post by WheezyRider » Feb 13, 2018 11:38 pm

I would be happy to bring my bike over to try out your controller - it sounds like a big improvement over the one the bike came with. Just let me know where & when.

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