Need details about this controller.

[Scrachdat]

Heyya, I am going to buy a cyclone 3000W motor, and a 60 Amp controller.

So problem is, My current battery isn't powerful enough to power the controller up to 3000W, so my thinking was to limit the current draw from the battery using the controller,

however a representative from luna cycles told me this wasn't possible, even though on the video provided it says it is possible and the documentation they have provided also says this is possible, I want to make 100% sure that it is possible. I'll put links to documentation video and the controller below aswell as some specs about my current battery.

Current battery, triangle battery from EM3EV, 937Whrs 33G cells max continuous current 28A max burst current 37A

Controller: https://lunacycle.com/60-amp-36-72v-ebike-bluetooth-programmable-controller/
Controller PDF: https://drive.google.com/file/d/0B9KXttJ6nbz6SXNxZjM0YUJhZms/view?usp=sharing
Controller video:

I will upgrade my battery in the future.

Thank you in advance.

 

[anotherkiwi]

Is it worth it? Your battery isn't going to last very long with that motor, my guess is a few weeks at most.

 

[Wheel-E]

Is it worth it? Your battery isn't going to last very long with that motor, my guess is a few weeks at most.

But surely if the current is limited in the controller to a sensible amount, it wouldn't put any extra strain on the battery?

 

[Deleted member 4366]

Nearly all controllers measure the current using the voltage drop across a shunt. It's normally pretty easy to change the shunt's resistance, so that the controller's cpu reads a scaled version of the current, which forces it to deliver more or less current according to the adjustment you made. increase the shunt's resistance value to decrease the current and vice versa.

You have to open the controller to see what type of shunt/s it uses before i can tell you how to adjust it.

 

[Wheel-E]

Nearly all controllers measure the current using the voltage drop across a shunt. It's normally pretty easy to change the shunt's resistance, so that the controller's cpu reads a scaled version of the current, which forces it to deliver more or less current according to the adjustment you made. increase the shunt's resistance value to decrease the current and vice versa.

You have to open the controller to see what type of shunt/s it uses before i can tell you how to adjust it.

I think he's talking about limiting current in the settings rather than via the shunt.

 

[Deleted member 4366]

I think he's talking about limiting current in the settings rather than via the shunt.

Yes, but if he doesn't have a setting to change, he has to do it by hardware.

 

[Scrachdat]

I think he's talking about limiting current in the settings rather than via the shunt.

Yes this is what I'm asking. Is it possible for me to limit the current draw using the controllers software, it does say it's possible in the pdf that you can do this.

I was just wondering if anyone has done it or knows anything about this perticular controller.

 

[Wheel-E]

Had a quick look at the PDF manual.

3.10 Battery Current Limit(A): Adjust the max output current of battery(50%~100%). Too small output current affects starting torque.
3.11 Phase Current Limit(A): Adjust the max phase current of motor(50%~100%). Too small phase current affects starting torque.

I'm wondering what the difference between 'Battery Current' and 'Phase Current' is. Probably a silly question but is battery current limiting the draw on the battery while 'Phase Current' ensures that the output current doesn't increase under load? Surely they're one and the same except for the losses within the controller?

 

[Deleted member 4366]

We had a discussion about that on ES a while ago. The way I see it is that the battery is connected directly to each phase of the motor, but blocked by the mosfets. All the mosfets do is block the battery and open for short pulses to allow the current into the motor, so the sum of the phase currents must always equal the current from the battery, I therefore reckon that the current limits that you can impose is a case of whichever one is lowest wins,

The whole thing gets a bit confusing because the phase current pulses are very short and at 6 times the frequency of the battery current. The average battery current(smoothed by a big capacitor, is equal to the sum of the averages of the phase currents, but the instantaneous phase currents are much higher, It's those that you have a chance to limit, which protects the mosfets, but I'm pretty sure that the controller uses an algorithm to calculate it based on the battery current because it has no way to measure phase current that I can see.