Display/control panel compatibility?

[Yurtrob]

Hi.

I've inherited a (probably) working ebike, but without the control panel/display and battery. The previous owner had more economical uses of his time than getting it working

[brothergc]

would be helpfull if We knew what we are working on , need more info .....

[Yurtrob]

Hmm, seems my post was truncated to the first few lines (?), so here's the info again, plus some more:

Motor: 36V, 250W, Brushless, rear hub
Controller- Tianjin Santroll B-WZKD3615KA-BD75-Z9
The manual says this bike has 6 pedal assist modes + walk mode. It has a ring sensor on the crank.
The lead to the missing display has 5 wires: black, red, yellow, blue, green.

I've found some other displays online with 5 assist modes + walk mode, but not six. I have no idea whether a display intended for another controller would work.

My plan is to test the motor with 3 12V lead acid batteries in series, but I have no way to switch it on or control it. Is this somehow possible without a display, e.g. by contacting the display leads? Photo of controller follows.

Thanks in advance for any help!

[Yurtrob]

[Tommycat]

Hi Yurtrob,

I've seen a lot of these type displays with the wire colors in this order, use the configuration as seen below in a wiring diagram I made for someone tying in a keyed switch...






Also typical for "KT" type displays, see page 3...
https://880b28d3d003e6b1c176-ee91599...en_KT-LCD3.pdf



There are always exceptions though. Perhaps opening the controller and seeing what the PCB terminals are labeled in regards to the display wiring would confirm for sure. Or at minimum checking from Black to Red for battery power.
Then you can check the rest of your components by jumping RED to BLUE of the display harness wires. Getting 5vdc regulated controller power after jumping will be a good sign. Then after checking the rest of your systems components, you'll know if further hunting for a display replacement for this controller is required. Good luck.


Regards,
T.C.

[Yurtrob]

Thanks for the info TC! I've done as you suggested and looked at the PCB connections. The labels on the PCB for the control panel wire connections are: Red - 48v, Blue - KEY, Black - GND, Green - SE0, Yellow - SE1. Do you think these labels are consistent with what you suggested for Blue, Green, Yellow (switched 48v to controller, Rx, Tx)? I'm going to go get some batteries so I can begin further checking now.

[Tommycat]

Do you think these labels are consistent with what you suggested for Blue, Green, Yellow (switched 48v to controller, Rx, Tx)?

Well done. Yes that is what I would expect to see...

[Yurtrob]

Hi!

I connected up 36v, and found the control panel wire voltages: Red-Black and Blue- Black +36v, Green-Black and Yellow- Black +0v.

After connecting Blue-Red, Green-Black and Yellow-Black went to +5v.

Sensor wires were +5v and -4v, so I turned the crank... And got pedal assist from the motor!

So I can now use the bike with at least one PAS mode, thank you so much! We live a little out of town, and my girlfriend really needed something easier than regular biking or depending on a lift. Now I can also feel a little less wasteful by not using my van for all those shopping trips.

My next questions are: is it possible to climb pedal assist modes by jumping the other cables, or do I need to buy a likely looking control panel and just try it? What are the risks with that? I still have the quandary of 6 pedal assist modes according to the manual, but only up to 5 on control units I've searched up.

I bought one 7.2 Ah 12v lead acid battery and wired it up with another and an old car battery for the test. I thought I'd go ahead and get two more 7.2s and use them in series rigged up to the pannier rack for now. Capacity fine should be fine for the length of journey, based on the original battery (9Ah) range. Any issues with that approach?I not particularly educated about batteries either.

Thanks again for your help!

[Tommycat]

... And got pedal assist from the motor!

Nice one! a step further... glad to help. :-)

My next questions are: is it possible to climb pedal assist modes by jumping the other cables, or do I need to buy a likely looking control panel and just try it? What are the risks with that? I still have the quandary of 6 pedal assist modes according to the manual, but only up to 5 on control units I've searched up.

I don't know of a way to "manually" change the pas level. As the displays communicate electronically with the controller and visa versa. (serial TTL perhaps) With each display/controller combo programmed to match with each other. The risk of course is that it won't work with money wasted . I would probably try the following ...

1) Find an OEM replacement thru a seller or after verifying exactly the one that was provided with your bike. A bonus if you stay close to the year it was made. Is it a Biltema by chance? Or make/model?

2) Find a display known to work with your controller. The back of one in this thread (with your controller mentioned)is shown with some numbers as well as a sellers web link... but didn't lead to a model for me.
https://endless-sphere.com/forums/viewtopic.php?t=93955

3) As you have the same wiring as a KT type display. A long shot would be to try one and be lucky enough to have it, or some/most things work... ( I have seen a couple successful tries, but mainly not) But if not, you could buy a KT controller known to work with your new display.

4) Not take a chance and buy a complete set that you like. (display/controller)

I bought one 7.2 Ah 12v lead acid battery and wired it up with another and an old car battery for the test. I thought I'd go ahead and get two more 7.2s and use them in series rigged up to the pannier rack for now. Capacity fine should be fine for the length of journey, based on the original battery (9Ah) range. Any issues with that approach?I not particularly educated about batteries either.

I would recommend buying a Li-Ion type battery or such if you plan on using this bike for any length of time. Expensive yes, but well worth the investment. Lots of comparisons about this subject on the internet to read about.
If not 3, 12 volt batteries will give you your nominal charge of 36 volts. It's the charging part that I would be wary of. I charge a bank of 12 volt deep cycle batteries with a solar charger. But they are wired in parallel, and can be charged with a normal 12 volt battery charger as wired. As well as the controller's battery Low Voltage Cutout may be off, something to check. Just some thoughts.

[Yurtrob]

Yep, it's a Biltema City Sport, but they don't sell parts like that off the shelf, at least. I'll ask in shop, but given a replacement battery is over $300, it's unlikely to be an economical option.

Probably buying a complete display/controller is best, and I can use it with no display and one assist mode while I wait for it to arrive. Can you confirm I just need something the same voltage and power, right? No compatibility issues between motor and controller, in terms of signals (again, I'm ignorant of such things).

Good to see that thread you pointed to. I may try to incorporate the brake switches into the system later, as this bike doesn't use them. I noticed it just powered through what seems like a good rear disk brake if I applied it whilst turning the crank - not so good!

[Tommycat]

Probably buying a complete display/controller is best, and I can use it with no display and one assist mode while I wait for it to arrive. Can you confirm I just need something the same voltage and power, right? No compatibility issues between motor and controller, in terms of signals (again, I'm ignorant of such things).

A good starting point would be the specifications on your existing controller. Yes you would match the voltage, (some controllers will handle multiple voltage input) and the current rated and maximum outputs. Note that your motor would most likely handle a bit more power... but this would be limited by your use of lead acid batteries, and their characteristics of poor energy output and voltage sag.

Motors can be sensored, using hall sensors to tell the controller the position of the motor. Or non-sensored. Typically a sensored motor has a 5 wire harness of small wires to it, with a non-sensored motor having 3 large wires. I am confused as to exactly what you have as your hand drawing shows 3 large, and 3 small wires going to the motor...? Can you clarify this? I'm thinking that the small 3 wires are for a speed sensor... If you undo them, does the motor still run correctly? If so you would definately need a sensorless motor controller.
Some controllers will do both sensored, and non-sensored operation. But you need to verify that. Size, mounting, and location may be a factor in choice. As well as extras...
Lighting control?
Would cruise be desired?
Would regenerative braking or even variable regenerative braking be desired? (errr $)
Sine wave verses square wave phase outputs?
Alarms and lock-outs.

The price may (or may not) go up with more features, but having knowledge of must haves and wants down ahead of time will help.

Good to see that thread you pointed to. I may try to incorporate the brake switches into the system later, as this bike doesn't use them. I noticed it just powered through what seems like a good rear disk brake if I applied it whilst turning the crank - not so good!

I'm a firm believer in brake switches that disable motor output, a must have in my book. Especially important if you have more than one rider, especially a novice. Whose first instinct is to hit the brakes when something goes awry.
So you may want to look for a kit with them included that can be used on your bike.