Brake switch wiring

[weirdfish]

As I'm contemplating converting the front brake of my Alien Aurora to hydraulic I thought I've have a quick investigation into the brake switch. I was expecting to see two wires coming from the switch back to the connector that I would have to either short or leave open circuit depending on how the switch operates. However, I seem to have three wires

I have no idea what the DIP switches are for but they don't seem to do anything that I noticed.

The cable/wires in question are marked in red in the pic.

 

[flecc]

I don't know the Aurora, but the switches might be magnetic, magnet in the lever and Hall sensor sending the signal when the magnetic field is removed.

Can you see if there's a moving switch plunger inside the brake lever body or just a face to face area?
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[weirdfish]

I thought it looked like a moving plunger but I didnt look that close as I just presumed that was it was. The levers are pretty cheaply made so I expected low end switch technology I'll have another look once the rain here calms down

 

[weirdfish]

It's definitely a plunge type switch.

 

[flecc]

I would have thought low-end too, but Hall sensors are cheap.

Otherwise the green wire could just be earthing the lever body (if metal) for some reason?

You could do a continuity check from green wire to lever body.
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[weirdfish]

The information on the wuxing website gives the following:

1.Trademark:Wuxing
2.Material: Bracket Plastic& lever Alloy.
3.Switch: Hight quality switch can stand 50,000 times of fatigue tests at 60V and 1.0A
4.The bracket and lever of some products are interchangeable.This allows brakes with various styles and dimensions to match different bicycle models and different brake's grasp distance.
5. Wire length: As your request
6. Connector: As your request
7. Line core: Two for mechanism, Three for Hall
2 electrical wires for Mechanism:
I.The Red wire: switch
II.The Blue wire: switch

3 electrical wires for Hall:
I. The Red wire: +5V(DC)
II. The Black(or Yellow) wire: GND
III. The White (or Green)wire: OUT

Not that I know what they mean by Line core .


I'm hoping that open circuit is normal as then I only have to disconnect the wires and be done with it.

 

[flecc]

Sounds like open circuit will be it, the Hall wiring just for when those levers are used.

Some Chinese multi-model handlebar controls have had unused push buttons in the past.

I think they just mean cable core, referring to it in terms of the electrical line to the levers.

 

[jbond]

I have no idea what the DIP switches are for but they don't seem to do anything that I noticed.

Can anyone throw any light on the dip switches? I haven't traced all the tracks but they seem to have something to do with the 4 resistors and the multimode switch control.

Perhaps it's a 24/36/48v setting for the throttle? Or a 24/36/48v setting for the battery health display?

 

[jbond]

Can anyone throw any light on the dip switches? I haven't traced all the tracks but they seem to have something to do with the 4 resistors and the multimode switch control.

Perhaps it's a 24/36/48v setting for the throttle? Or a 24/36/48v setting for the battery health display?

Related question. What is the default setting for the Aurora and Alien 36v kits that have this wiring concentrator? Inevitably I didn't write it down before messing with them. weirdfish, you've got both off in the photo. Is that how they started?

 

[weirdfish]

yeah that's exactly as it was when I took the cover off.



You had any joy finding out what they do?

 

[flecc]

The Sunstar motor kit has a row of DIP switches which are claimed to be optimisers for different wheel sizes, rather odd for a unit that drives the bike chain though. I've no idea how they do that, and one owner declares he can observe little difference in which is chosen but has chosen to leave it on the highest level

That sort of selector would make more sense for a wheel-hub motor which has to cope with different rim diameters, so I've offered it as a possibility.
.

 

[jbond]

You had any joy finding out what they do?

Nope. I can't feel any difference.

I really should take the time to trace it through. Taking your photo. It looks to me like a red 36v feed comes in from the left. Then there's the horizontal resistor. The other end is connected to the lower end of the three resistors and to some feed into the throttle and/or switch unit. One of the resistors goes to earth and the dip switches switch in and out the other two in parallel. So its a voltage divider with potentially 4 different values to drop the input 24v/36v/48v to (say) 12v. I'd expect the throttle to have it's own 5v limit so it always returns 0-5v regardless of supply voltage. So the most likely thing is that this feeds a battery reference value to the switch gear. In which case the one thing you might see is that the battery health indicators behave differently for different dip switch settings. But I've tried this with both DIPs on and with both off with no obvious difference.

Anything to do with the speed is going to be inside the controller rather than out here on the wiring concentrator. The 3 mode settings would probably just be 0 or supply +ve on 2 wires back to the controller this then tells the controller to pick one of three motor control strategies.

Bizarre.

 

[weirdfish]

If the weather holds ok at the weekend I'm going to possibly change the front brake so I will have a closer look myself. As long as I can isolate/override the front brake cut off I'll be happy.

I do admire your quest to speed the Beast up tho

 

[jbond]

Ok. This is not the whole story but I'm closing in on it.

The dip switches on mine had been squashed and broken the connections at the bottom. So no matter what I did to the dip switches nothing happened. They were both off. So I remade the solder connections and had at it with a multimeter. The DIP switches have no effect on the switch gear, brakes or throttle. But what they do is to vary the voltage on the blue wire (4) back to the controller. This is also varied by the mode selected on the switch box. IN Medium. Both off = 1.8v, 1on-2off=1.0v, 1off-2on=1.2v, 1on-2on=0.8v. One last thing. High mode, both off=2.4v

Now get this. With both off, I get the familiar 12mph-16mph-21mph top speeds for the three modes. But both on, all three modes have a top speed of 12mph.

So what we have here is a single wire going back to the controller that sets a voltage that sets the top speed limit provided by the controller. This voltage is set first by the switch box mode setting and secondly by a resistor array controlled by the dip switches. You can see where this is going. I bet if we can arrange for the line to have a voltage of >2.4v we can remove the top speed limit. With both switches off, the blue wire links off the join of the top right resistor and the horizontal lower resistor.

 

[daniel.weck]

I have no idea what the DIP switches are for but they don't seem to do anything that I noticed.

I don't know what the dip switches are for, but this definitely looks like the new (-ish) 8-Fun E-BUS system. EDIT: oh yeah, it's written on the PCB

http://www.pedelecs.co.uk/forum/electric-bicycles/5353-neat-8-fun-suzhou-bafang-cable-connectors.html#post68693

There seems to be several PCB models (high-res photos):

http://daniel.weck.free.fr/BromptonBafangTongxin/8-Fun_E-Bus_Front.jpg

http://daniel.weck.free.fr/BromptonBafangTongxin/8-Fun_E-Bus_Back.jpg

http://daniel.weck.free.fr/BromptonBafangTongxin/8-Fun_E-Bus_BackOther.jpg

 

[weirdfish]

Strange how the investigation has changed from a desire for better braking to how to get more speed


How I read the back of that pcb, it seems like the brake cut off switches are wired in parallel and therefore must be open circuit in their inactive state. If that's the case then it's just a case of unsoldering the cut off switch in question from that connector box and that should be it.

Right, more speed............

 

[jbond]

I think I've got this straight now.
Controller side:-
1 Brown - 36v to the mode switch
2 White - 0v to the mode switch
3 Orange - To the Blue wire Mode switch ??
4 Blue - Mode set, Max Speed, Off. 0v to 1.8v depending on mode and dip switches
5 Red - +5v to the throttle and the brake switches
6 Yellow - Throttle signal. 0v to ~4.5v depending on throttle position
7 Black - 0v for the brake switches and the DIP switch resistor ladder
8 Green - Brake switch signal

Mode Switch
Red - +36v
Black - 0v
Blue - +5v?
Green - on/off, mode signal

Throttle
Black - 0v
White - signal
Red - +5v

Brakes
Brown 0v
Green signal, pulled to 0v when brakes activated, floating when brakes released. So the switches are normally open with the brakes released.
Red +5v Hall effect power?

Dip Switches
Mode switch signal out is ~3.6v in medium
Both Dip switches off, this is connected to ground via 2* 10k resistors with the mid point taken to the speed signal 4-Blue so 1.8v
The dip switches put one or two 20k resistors in parallel with the ground side 10k to reduce the ground side resistance to 6.6k or 5k. This reduces the max speed signal to the controller from 1.8v to 1.2v

The speed signal voltages don't quite match what I found. I'm not completely sure I'm reading the small 5 band resistors correctly. I think they're 10k-1%. Going to do a bit more checking today. I think the same mode switch is used for 24/36/48v So I expect a dip switch in there purely for the battery health display. I think the mode switch expects to always receive 5v and the mode signal back out is just something like 100%, 70%, 40% of this. With both dip switches off, this is cut in half before being fed to the controller max speed input.

Now the motor says 36v/350w (13)26. I take this to be 350w continuous Version 13, wound for a 26" wheel. The controller says 18A, Rated 9A. So I think that's peak 18A, continuous 9A. 9*36 = 324w, 9*41v= 369, so that more or less matches the motor's 350w. 18*36= 648w, 18*41v=738w I would have thought the motor is easily capable of handling this at peak and may well stand it continuous as well without overheating. I think this means the battery is expected to deliver 0.8c to 1.8c. Again, I would have thought the battery is easily capable of supplying this. I figure the controller is allowing up to 18A as a hard cutoff and has a motor rpm speed limit controlled by it's signal wire. The unknown is how high this rpm speed limit can be pushed, given the motor-controller pairing. eg what happens if you put 3.5v or 5v on the controller max speed signal wire? I can't imagine the controller will just run away as it should still have a hard sanity limit both on rpm and current draw.

What might happen though is that the controller has 3 states. Approximately, <1.0v = low mode, 1.0v to 2.0v = medium, 2.0v->5v = high and the rpm limit is then set in software inside the controller. This would match my understanding of the infineon based controllers.

 

[flecc]

Now the motor says 36v/350w (13)26. I take this to be 350w continuous Version 13, wound for a 26" wheel. The controller says 18A, Rated 9A. So I think that's peak 18A, continuous 9A. 9*36 = 324w, 9*41v= 369, so that more or less matches the motor's 350w. 18*36= 648w, 18*41v=738w I would have thought the motor is easily capable of handling this at peak and may well stand it continuous as well without overheating. I think this means the battery is expected to deliver 0.8c to 1.8c.

There's a lot of parity between these figures and those of the original SB motor in the old eZee Torq 1, which was a 22 mph e-bike. That motor easily sustained those "peak" powers continuously without temperature rise and was capable of true peaks very much higher with the eZee controller and an adequate battery.
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[jbond]

Another thought about those DIP switches. The same control switch box could be used on a legal and on an illegal bike. Flick one DIP switch on and the bike becomes legal (more or less) with a max of 16mph regardless of mode. Otherwise I can't see what the point is.

 

[weirdfish]

Well I can confirm that you can safely remove the brakes cut off switch, leaving it open circuit.