810 and ku65 controller - PAS pedelec question

[dgncsk]

Hello. I finally bought another 36v controller and its 810 led panel. i received it yesterday and installed. PAS is working. front wheel is turning. Also bought a throttle for my ebike and it is also opertional and it works as intended. queston is...

there are pas settings 1 2 3. these numbers only overrides the top speed of motor in contrast of my other ebike set which is Bafang with LCD screen and a seperate buttons to adjust settings. When i set pas level to 1 on bafang it only give me little push. when it is 4 or 5 it give more power than required as long as i use pedals.

what is wrong with 810? or is it the way it operates? it feels like, it mimics the torque sensor only by using speed input.

 

[Deleted member 4366]

It's a speed control controller. The PAS works the same as the throttle, but with three fixed settings. The power algorithm provides high power that ramps down to zero when you reach each speed setting.

Other controllers, like the S06S and S06P use current control, so each of the 5 PAS settings are a different power level, which stay constant regardless of speed.

Both systems have advantages and disadvantages. the speed control controllers allow you to pedal along with very little or no power until you start to slow down because of a hill or wind, then they automatically feed in more power in an attempt to maintain one of the three target speeds, so you don't need to press any buttons. The downside is that you always start with high power.

The current control ones give a much softer start (on low setting), but they give the same power all the way up to the max speed limit, so you have to keep pressing buttons as you go up and down hills.

If you don't like the maximum power at start up, you can fit a normal handlebar switch to one of the brake connectors so you can cancel the power to the motor when you want. the throttle always takes precedence, so another thing you can do is open the throttle a small amount when you start, or use the throttle when you need precise power control.

 

[dgncsk]

very informative post. thank you for explanations. i don't like how it starts then, because on smooth surface, my front tire tries to spin which i do not want this happen on wet grass..

throttle can give little power to motor so it can spin at very low speeds as expected( during starts). i will try to use throttle first if it is able to override the PAS.

few more questions.

what is high level brake? what is low level brake? ( motor is geared hub as you may guess) most important, what is three speed connection? ( will this applies to PAS speed? i dont want 25 km/h for example, i want 6 km/h... )

 

[Deleted member 4366]

High level is when you feed 5v to the brake switch. The brake switch will connect the signal wire to it, so the controller sees high (5v) when you operate the brake. For low level, the switch is connected to ground and the sensing wire is pulled up to 5v by a pull-up resistor in the controller. When you operate the brake, the sense wire is grounded, so the controller sees a low (0v) signal.

That means that the controller will cut all power if it gets 5v on the high brake wire or 0v on the low one.

The three-speed connector is interesting. It can make your motor go faster than it would with a normal controller as long as it's a hall sensored motor. The middle wire is ground. If you connect nothing, you have normal operation, like any controller. If you connect that middle wire to one of the other two, you get restricted mode, which is about 15 mph, depending on wheel size. If you connect it to the other wire, you get turbo mode, where the controller alters the timing, which makes the motor run about 10% faster. You can either use a three position switch to use those things or, just put a switch between the boost wire and the middle one to get a boost when you're already going fast. It doesn't increase the power or torque and will be less efficient for climbing, so best not to leave it on all the time. you have to test to see which is the fast and which is the slow wire unless they tell you on the BMSB wiring diag download.

 

[dgncsk]

Thank you for your response. It seems that i need to get used to use little bit of throtle at start instead of waiting PAS kicks in since it is really faster than expected. So here is the question rises on my mind... if throttle is overriding the PAS ( i tried this after reading your post) and if ARDUINO used to detect PAS movement from its hall sensor by feeding it 5volts and reading the signal on a analog input of arduino, and if arduino software turns on throtle at minimal level ( i dont know how to do yet) would it work?

 

[Deleted member 4366]

There's loads you can do with an Arduino. You can have infinitely adjustable PAS speeds and put a ramp on the output so that it feeds in gently. The PAS signal is pulsing 5V, so you have to read it as pulsing or not, then send your output as a throttle signal to the throttle connector. You can simply splice the throttle signal wires so that highest wins.

 

[dgncsk]

I will try this. While thinking details on Arduino, today we went to a very short tour. I cant differentiate the pas levels. Low mid hi all has same effect. Is there something i missed? There is a light on off switch which controls a wire with
36 volts. But shouldnt there be a function to walk together with bike? 6 km/h limited speed setting is there on my Bafang lcd.
.

 

[Deleted member 4366]

There's two versions of the 810 display. One has a light switch, the other has a 6km/h button. If you want the walk assist function, you need to send exactly 4v down the green signal wire from the display. 1v is level 1 2v is level 2, and ......see if you can guess .................................3v is level 3. With no signal, the controller defaults to level 1.

The three PAS levels are speed controls, not power levels, so if you're travelling at below 8 mph, there will be no difference. At 15 mph, only level 3 will give power.

 

[dgncsk]

Yes i realized that today. I think i prefer light switch.

Regarding to the logic behind PASis making me to think and find the way to alter. I will inform on a seperate topic. I think i will remove connection of pas sensor and use throttle to go slow and conserve battery power temporarily.

 

[Deleted member 4366]

You'll conserve more power using the PAS. It initially wastes power, but it'll use less when you get to cruising speed. It's impossible to hold the throttle still while you're riding, so you'd waste power at cruising speed unless you make some sort of cruise control, which is very easy if you have a thumb throttle.

 

[dgncsk]

I Agree. But it is not ok when i try to go very slow uphill. I wish there would be speed adjustment. On bafang kit i adjuated 1st pas setting to only 20watt, 3rd to 120watt. 5 is 350w.

 

[Deleted member 4366]

If you wanted it like that, you should have bought the S06S. The KU65 is a cheap controller with a cheap display and less functions.

 

[dgncsk]

i wish i knew that... i was wondering what could be the imitaiton torque controller.. now i know.

i started to my arduino project today. i will report later.

yesterday we took a short trip again. only 6 kilometers. it does conserve power when i use throttle only when needed and disable pas by disconnecting.

i had built my battery with 15C sony batteries. it is BMS equğipped 10S pack only and very suitable for our casual activities. i think it will have 12-15 km range. which is perfectly ok for my needs since i kept its weight low.

 

[dgncsk]

a question... is throttle signal to controller, on signal cable a PWM or analog DC?

 

[Deleted member 4366]

The normal throttle is analogue signal 1.2 to 3.8v (approx). Some controllers will shut down if the signal goes over 4v, though most are OK with that. All controllers need to see a signal of 1.2v or lower during initialisation before they'll give power.

You can use your Arduino to PWM the throttle, but you need to include a low pass filter on it to smooth it out so that it's like an analogue signal. From memory, that's a 1K resistor and 1 microfarad capacitor, but I can't guarantee that those values are correct.

 

[dgncsk]

there is a simulation environment called circuits.io

i set an arduino there and wrote/modified a sketch. it works! now it is time to adapt it to reallife. i have an arduino nano. so i will measure throttle votlages first, and adjust arduino program accordinly.

this is how it acts.

panel has 2 3 4 volts as output to set the speed limit for cruise control like action ( which i do not like). panel will send 2 3 4 volts to arduino this state is recorded. and there is hall sensor signal. it is 5 volts in a form of square wave. so it is digital input. i keep track of it by using a digital pin and count it. ( actual code was for speed meter for bikes from instructibles.) so this can also track the cadance and can calculate calories burned too! (by approximating the power use). it uses timer functions and interrups and if else conditions. i added panel and throttle settings and some conditions. when pedal is in use, and if panel has 2 volts arduino gives 1.2xx volts to throttle signal wire and there is a diode to prevent feedback on throttle signal. ( 3 volts for lets say 3.3 volts on throttle, 4 volts is for max power lets say 4.6 volts). when no pedal signal, no power from panel to throttle.

 

[dgncsk]

here is my test bench.

https://circuits.io/circuits/5071478-pedelec-controller-signal-alteration-v-2-0

 

[Deleted member 4366]

Here's how I'd do it:
10k linear pot on analogue input
Pedal sensor signal wire on digital input (read pulse)
Throttle output signal on pwm output with low pass filter
Throttle to analogue input

Read the throttle signal. If more than 1.2v, send the equivalent signal out of the output
Read the pedal sensor input to see if the pedals are turning.
If yes, read the pot signal.
Give throttle output proportional to pot input

That way, you can have a continuously variable PAS with throttle override.

Disconnect the signal wirefrom the 810 because you won't need it anymore.

There's different types of pedal sensors. Ideally, you need one that only gives a signal when turning forward, otherwise you have to figure out how to use the duty cycle to determine forward direction only.

 

[dgncsk]

before turning direction related problems, my pass filter making attempts failed. actually i cant figure how PWM acts without an oscillator here. on simulator it acts correct. even when i try simple led fading sketch it reads 2.6 to 3 volts on my cheap avometer without any low pass filter. led fades in and out.I never read approx 5 volts on output pin.

on my pedelec fdesign there is absolutely no voltage output on PWM pin. besides of this, PWM never reaches 5 volt on open circuit too. i measure it is around 3 volts all the times. to many variables to think for me now.

i am lost.

 

[Woosh]

if you make a low pass filter to convert a PWM to a voltage, the output depends on the R and C values of your filter. It will take a lot of guesswork to find the appropriate values for R and C. You can use one of the analog inputs to measure the throttle voltage (by connecting your PWM output to it) and adjust your PWM accordingly.

edit

The controller can't receive an unfiltered pwm throttle signal. it'll just go nuts.

d8veh is correct, connect the output of your low pass filter to an analog input, not the PWM pin.
I suggest you test with 5 kOhm variable resistor and 0.1microF capacitor.