Help! Torque Sensor mod?

[AdrianN]

My wife and I both have Carrera Subway e-bikes that have Suntour Torque sensors.

We both love the bikes, but my wife has recently developed a knee injury and finds the cycling effort too much on the knee.

She has tried an Apollo e-bike that has a simple Cadence (on/off) type sensor, she finds this much easier and can pedal with almost zero effort and the bike just goes along. She wants to pedal a bit and not use a hand throttle.

We don’t want to change her subway as the Apollo is a much lower spec bike, so is there a way to mod the Subway to:

• a. Change the sensor and or controller to a simple on/off type similar to the Apollo
• or
• Adjust the Subway senor to reduce the torque effort needed to give more power output

Thanks for any guidance

 

[Woosh]

I don't think you can adjust the Subway.

 

[sjpt]

If you are considering replacing the Woosh Santata 3 (NOT the CD) looks as if it might suit. http://wooshbikes.co.uk/?santana3. A little more than the Subway but probably (I haven't looked) better specs; especially battery size which is likely the main reason for the price difference. (Very restrained of Woosh not to mention it)

 

[vfr400]

You have to replace the controller and LCD, then do some basic wiring and solder some wires. Cost is about £70 if you want a nice control system or as low as £40 for an average control system.

 

[Woosh]

You have to replace the controller and LCD, then do some basic wiring and solder some wires. Cost is about £70 if you want a nice control system or as low as £40 for an average control system.

you may have under-estimated. On top of the controller, controller housing and LCD:
He'll need new cabling system, the motor connector is Suntour's and will need replacing.
He can't install standard pedal sensor to the Suntour chainring.
If he fits the throttle, he'll have to fit sensored brake levers or inline brake sensors.
They all add costs and time.
The simplest way is somebody makes an add-on board for a throttle and tap into the Sunsour's torque sensor circuit.

 

[vfr400]

Don't need brake sensors.
Pedal sensor goes on left side
Cabling comes with the LCD and controller.
You keep the Suntour connector and solder the controller end of the motor cable to the new controller.

 

[Woosh]

Don't need brake sensors.

If you have a bad knee, you would like a throttle as a backup.
no brake sensors, no throttle.

Pedal sensor goes on left side

I think the HESC's bottom bracket has a sleeve around the axle.
The diameter of the bottom bracket axle of the Suntour kit is too wide for the left side pedal sensor and the splines on the BB may not match the splines on the pedal sensor.

 

[AdrianN]

Wow, that’s a lot to take in, thanks for all the reply’s I will need a few hours to digest

 

[AdrianN]

Any chance of some links to the parts I will need please

 

[vfr400]

Assuming that you have a soldering iron, solder and a multi-meter,:

24V/36V 250W 6Mosfets 15A Brushless DC Sine Wave Controller - PSWPOWER.com

www.pswpower.com

Click on throttle, LCD3 and 10 poles PAS. For the sake of £2, it might be worth getting the speed sensor too in case the one in your motor ever gives problems.

https://www.ebay.co.uk/itm/328pcs-Heat-Shrink-2-1-Tubing-Tube-Sleeving-Various-Sizes-1mm-14mm/323337869022?hash=item4b487056de:g:WFAAAOSwVH5bjoUI

In the worst case and/or if you're incapable of doing simple modifications, you might need one of these. there are several different lengths. You can choose one longer than your present one because length isn't an issue on your bike and longer means more space for the pedal sensor.

VP-BC73 68 x 110.5mm Square Taper Cartridge Bottom Bracket

The VP-BC73 68 x 110.5mm Square Taper Cartridge Bottom Bracket is a sealed unit with a tough barrel.

www.halfords.com

 

[AdrianN]

Thanks vfr400 plenty for me to research there

 

[vfr400]

It's not really that difficult to do if you can solder. You get the added benefit of programmable speed limit and addition of a throttle.

 

[AdrianN]

I can solder no problem, I have built lots of electric r/c cars and planes and have a reasonable understanding of electrics, but by no means am I a Sparky.
So I am ok with the project as long as I understand what all the but do, how they connect together and mount on the bike.
So let’s see if I get it:
Replace the controller
Replace the LCD panel
Remove the existing crank sensor and fit the new one, possibly onto a new crankshaft
The sensor detects that pedalling is happening and sends a signal to the controller to send power to the motor
The thumb throttle provides a throttle function, but is this actually needed? If the throttle is not used is max power just sent to the motor?, or am I missing something
Where does the speed sensor go and what does it do?
Sorry for the questions, The PSWPOWER site does not give much info on the parts
What functions does the LCD do, does it have preset power settings, low, med, high like the bike Suntour LCD, or if not is that why the throttle is needed.

 

[vfr400]

A throttle isn't necessary, but is extremely useful. It doesn't affect the pedal assist in any way. It gives variable power, like on a motorbike or car.

All those devices have matching connectors, so just plug in.

The 9 motor wires and 2 battery wires need to be joined to the controller by soldering.

 

[Nealh]

Where does the speed sensor go and what does it do?
Sorry for the questions, The PSWPOWER site does not give much info on the parts
What functions does the LCD do, does it have preset power settings, low, med, high like the bike Suntour LCD, or if not is that why the throttle is needed.

Speed sensor isn't required if the hub motor has an internal sensor.

LCD has 5 PAS assist levels set to approx. 13%,20%, 33%, 50% & 100%.
Other main screen functions are watt/voltage reading, trip, odo, speed .
Speed setting can be changed to (in most cases) max out the hubs windings/rpm speed. Current can be set lower if required and several other settings to tailor an install.

 

[vfr400]

The speed sensor goes on a chain-stay or your fork and a magnet goes on your wheel. It's the same as the sensor on those bicycle computers. in fact, you can cut off the sensor from a bicycle computer and use it instead. You have something similar inside your motor already wired in to the motor connector, but they often give problems. The external one would be insurance against that, and it at least has the correct connector.

 

[AdrianN]

Brilliant, thanks for all the help,
If wifey is happy with the mod and it takes her less effort on the pedals, it will be worth it... hugely