What e-bike controller

[vladobac]

Hello everyone.
I have a bicycle with a 36V/250W rear motor with the marking CZJB26" 36VS24225455. The motor also contains Hall sensors and has a 9-pin round connector. The controller has a maximum of 15A on the label, marking 36VLD6G. It has 5 levels of support, switched by buttons on the handlebars and indicated by 5 LED diodes. Without a display. The motor is activated by the PAS sensor or throttle. I am a more active cyclist and ride up to 10,000 km per year, mostly on the flat. I most often use only the 1st level of support, so that I can also get some exercise and increase the bike's range. I don't like that this controller helps too much even at the lowest assistance and has an uneven ride. It quickly overheats on hills when using stronger assistance. However, its great advantage is the unlimited speed at all assistance levels. In practice, even at assistance No. 1, the bike forces me to engage the heaviest gear in order to be able to contribute to the movement of the bike. In lighter gears, I only imitate pedalling, because the motor does all the work and it only needs me to activate the PAS sensor. So I practically ride permanently in the heaviest gear, which of course wears out unnecessarily quickly.

I measured the current draw from the battery for each assist:
Assistance No. 1 draw 5.6A (at 36V 202W!)
Assistance No. 2 draw 8.2A (295W)
Assistance No. 3 draw 10.2A (367W)
Assistance No. 4 draw 12.5A (450W)
Assistance No. 5 draw 16A (576W)
It is clear that assistance No. 1 is unnecessarily oversized for an active cyclist. I contacted the bike dealer and he wrote back that the manufacturer told him that it could not be changed. I think that support would suit me, for example, something like this: 100W, 150W, 200W, 350W, 500W.

I am looking for a controller with a weaker initial assistance (ideally adjustable), smooth operation and, most importantly, without a speed limit. Price approx. €100 for controller + display. I do not want my motor to turn off when I am actively helping it.
Thank you for your tips.

Vladimír

 

[vladobac]

The KT controllers you referenced have a couple of ways to adjust power and assist in their setup menu, and have selectable power/current/speed control modes.

Perfect, I have to translate it because I don't know English. Could you advise me on how to set this particular controller via the LCD5 display to meet my requirements? Approximately 100W, 150W, 200W, 350W, 500W and no speed limits? The motor must constantly assist while pedaling, regardless of the assistance level.

 

[stancecoke]

Approximately 100W, 150W, 200W, 350W, 500W

The Kunteng has no possibility to define custom levels. I doubles the power with each level approximately. If level 5 is 500W, then 4 is 250, 3 is 125 and so on.... That's better than linear for simple PAS power levels, but not changeable by the user. Only the max power is settable.

 

[E-HP]

Perfect, I have to translate it because I don't know English. Could you advise me on how to set this particular controller via the LCD5 display to meet my requirements? Approximately 100W, 150W, 200W, 350W, 500W and no speed limits? The motor must constantly assist while pedaling, regardless of the assistance level.

It’s not your solution. Im pointing out how you can go about looking for a solution by looking at the available info in the manuals. Im not going to do your research for you, but others have suggested places to start.

 

[vladobac]

It’s not your solution. Im pointing out how you can go about looking for a solution by looking at the available info in the manuals. Im not going to do your research for you, but others have suggested places to start.

I understand, thank you

 

[E-HP]

I understand, thank you

Having followed a similar path as your own is, the most difficult transition from the engineering way of thinking, and the real world is compromise. Finding a solution that meets your exact criteria and budget is like finding a needle in a haystack. Be careful thinking you know the precise solution to the issue, since there may be several that would be acceptable but within your budget,
My advice is don’t modify a prebuilt ebike, especially a cheap one. Just ride it and adapt to what you bought and have fun. Work on converting a bike you like,taking time to select just the right components.

 

[stancecoke]

Finding a solution that meets your exact criteria and budget is like finding a needle in a haystack

That was the reason for me to write my own controller firmware. Now the controller does exactly what I want
I started with an additional pre-controller, similar to the Cycle Analyst, but having full access to all controller functions directly is much smarter and easier to install on the bike.

 

[vladobac]

I don't understand why universal controllers aren't made where you can adjust the assistance power for each level. I know that each motor has a different performance characteristic, but the user would adjust it to suit him as much as possible. The numbers would be different for each motor, but in the end the bike would behave as the user wants. This solution would have to suit everyone. Of course, the controller must also know the other functions, such as display brightness, km vs mph, reaction speed, smoothness of start-up, sleep time... But the most important thing is the power with which the bike assists us at each level. And the speed limit would be uniform for all levels. And that's just to comply with safety regulations in individual countries. And of course it should be possible to cancel it if the user is moving around his property.

 

[stancecoke]

I don't understand why universal controllers aren't made where you can adjust the assistance power for each level.

?! Just buy a one. With the Lishui, you can do that, see #5

Controller

Unsere Controller für unsere aktuellen Umbausätze werden in der V2-Version ausgeliefert. V2-Controller haben Stromstufen und verfügen über eine…

www.ebike-solutions.com

 

[vladobac]

I really like it, but display + controller + cabling = €250. That's uneconomical for me.

 

[E-HP]

I really like it, but display + controller + cabling = €250. That's uneconomical for me.

Make a voltage divider with a couple of potentiometers, activating the circuit with a push button, run the circuit in parallel with the throttle input using the 5v and ground from the throttle connector. Adjust the pots to provide your desired throttle input voltage for the level of assist you want. Ride, and press the button when you want the assist. Turn the knob on the pot to adjust the amount of assist. $3 in parts at most.

 

[stancecoke]

Make a voltage divider with a couple of potentiometers

This would limit the speed, not the power. The standard throttle input sets the duty cycle, the current is resulting from the speed...

 

[E-HP]

This would limit the speed, not the power. The standard throttle input sets the duty cycle, the current is resulting from the speed...

For $3, it's worth a try.

 

[vladobac]

Make a voltage divider

Good idea. I'll look into it.

 

[stancecoke]

For $3, it's worth a try.

The result is very predictable. The bike will accelerate with maximum power to the speed that belongs to the throttle position. If you want to ride faster, the motor not assists any more, it will just turn with the constant speed in the freewheel. If you get slower due to a hill, the current will rise until it reaches the battery current limit. I don't believe, that this is the behaviour, that @vladobac wants

 

[E-HP]

The result is very predictable. The bike will accelerate with maximum power to the speed that belongs to the throttle position. If you want to ride faster, the motor not assists any more, it will just turn with the constant speed in the freewheel. If you get slower due to a hill, the current will rise until it reaches the battery current limit. I don't believe, that this is the behaviour, that @vladobac wants

He has the knob on the pot to adjust on the fly, and although not ideal, it’s a compromise that fits within his budget, so it’s not a big investment to experiment with. At least tuneable compared to the fixed settings and behavior he’s experiencing now. (Plus, maximum power on that bike is hardly called acceleration).

 

[vladobac]

Sorry, I won't be able to answer for a while, I'm trying to take apart the silicone controller to see if it will be possible to adjust it. It's not user friendly.

 

[99t4]

The price of my bike was €579, so it's pointless to invest, for example, €300 in it...

I don't always agree with this mode of thinking. If the investment measurably increases your enjoyment of it, or increases reliability, performance, or extends its lifetime, it may be worth it. Especially for a component that you can easily remove and install it on your next project.

 

[vladobac]

Možno by fungoval aj „shunt mod“.

Your solution works. Thanks for the great tip. I increased the shunt value more than twice and the assist power decreased proportionally. Thanks to everyone else for the help.
And I have a second problem, namely jerky, uneven engine operation. Especially at a lower assist level. By adding power by switching to a higher assist level, the vibrations weaken until they completely disappear. I would like to point out that the above condition is not a malfunction that occurred during use of the bike, but that it is an imperfection of the controller from the factory. After buying the bike, I complained about it and the Chinese sent me a second wheel and controller. However, the replacement did not help, the problem still persists. It is possible to ride it, but I would like to improve it. I am attaching an audio recording from the start, where from the 19th second you can hear jerky, uneven engine operation. As if the controller was vibrating. I would appreciate a good tip for this problem as well.