Giant Twist Express RS2 - No Power

[saneagle]

The torque sensor is not a common one. If it has three wires, two will power it and one is the signal. You can easily measure them to see what happens when you figure out how to switch on the controller that looks standard to me and should work like I previously explained.

 

[PointyUK]

This is what I have come up with for the display schematic...



If you spot anything you think is wrong, let me know.

 

[saneagle]

The switching doesn't look right. All the ones I've studied use a MOSFET or transistor to do the switching. The on/off needs to latch. I never analysed it, but I assumed that when you press the on/off switch, it makes a temporary connection that powers the CPU and also works as an input to the CPU. When the CPU is powered up, the default state of the output leg that controls the MOSFET is on, but when you press the on/off switch again, it works as an input that tells the CPU to make the output signal to the MOSFET go low, thus switching it off.

Also, in your schematic, the control panel would be powered all the time, which would drain the battery.

 

[PointyUK]

Also, in your schematic, the control panel would be powered all the time, which would drain the battery.

Anything with a soft on/off button must be powered all the time. If the MCU is in standby it will only draw a couple of ua anyway.

 

[PointyUK]

I can answer my own question about the torque sensor voltage as I can trace it back to the 5v line.

Unfortunately I think the controller is fried as there is 26v on the 5v line.

Tomorrow I will try and test the torque sensor.

 

[PointyUK]

I would like to try and test the motor today and just want to make sure that I don't do anything stupid.

My other eBike is an Apollo Phaze 24v. It has a Shengyi DWG07C-FA motor, I haven't opened the motor yet as I need to get or make a special tool, but I looked at this thread and this video.

It looks like phase A is green, B is blue and C is yellow. The Giant motor is A, (brown) B (white) & C (grey) looking at the controller legend.

As I have to change the motor cable on the Apollo I bought a 9 pin extension lead, so my plane is to cut the female end of the extension lead and connect the wires to the Giant motor. I have read that you can destroy the controller if wired incorrectly so as an e precaution I will power from my bench supply with the current limiting turned down.

Any thoughts?

 

[PointyUK]

So after making the following test cable...



It didn't work, although it did appear the motor was trying to go backwards and drawing way to much power. After swapping the yellow and green wires round the motor worked as expected.

Of course although the colors are the same in the extension cable, it doesn't mean they are in the same order. I need to double check when I replace the Apollo cable.

I then set about testing the torque sensor, which was outputting about 1.4v on the brown wire and didn't appear to change when turning the peddles. However when holding the back wheel and trying to peddle the voltage went up to about 2.5v, so I assume this is working.

 

[PointyUK]

So I came up with a novel way to test the battery...



I then when for a 5 mile ride, including some steep hills at full power. The display was still showing full when I got back and the voltage was still 27v+.

Due to the lack of Giant parts in the UK and the cost of a controller (189 euros + shipping ), I am leaning towards replacing things with a KT controller and display along with a PAS sensor for a fraction of the cost. Any other recommendations will also be considered.

 

[saneagle]

So I came up with a novel way to test the battery...

View attachment 57489

I then when for a 5 mile ride, including some steep hills at full power. The display was still showing full when I got back and the voltage was still 27v+.

Due to the lack of Giant parts in the UK and the cost of a controller (189 euros + shipping ), I am leaning towards replacing things with a KT controller and display along with a PAS sensor for a fraction of the cost. Any other recommendations will also be considered.

Go up to 36v. It'll make the bike much better.

 

[PointyUK]

Go up to 36v. It'll make the bike much better.

I am sure it would, but I have to get this bike up and running as cheaply as I can for the missus.

At some point in the future I want to do a conversion on my Land Rover MTB and of course as it is for me, there will be no expense spared.

 

[PointyUK]

Having decided to replace the controller, display and torque sensor, I finally have all the parts...

BMS S06S Controller.
KT LCD4
KT-V12L

I hooked it all up, using the bench supply and it appears to be working, I just have one thing to sort out. The Giant speed sensor is just a reed switch/sensor (2 wire) can this be used with the controller? Is it just expecting a positive pulse, if so can I just connect the red/white wires? (Motor has no speed sensor wire)

 

[thelarkbox]

Not the red wire thats +5v

google confirms

How to wire a 2 wire speed sensor?


Wiring of speed sensor

Run one wire from the speed sensor to the RPM terminal in the rev limiter box. Run the other wire from the speed sensor to the ground location. As the two wire speed sensor is a non- polarized AC sensor, either wire can be run to the RPM terminal and/or ground.

 

[saneagle]

Is it just expecting a positive pulse, if so can I just connect the red/white wires? (Motor has no speed sensor wire)

If it's a two-wire sensor, it's a reed switch, and it will work. You connect one wire to the signal (white). The second wire will go to one of the other two, which you have to get by trial and error. Logically, if the signal wire rests high, then the other goes to ground, and vice versa.

 

[PointyUK]

Logically, if the signal wire rests high, then the other goes to ground, and vice versa.

Signal wire is held high, so I will try between signal and ground.