VESC in electric bicycle

General topics and discussions about the VESC and its development.
inteltechnic
Posts: 3
Joined: 03 Apr 2016, 20:11
Location: moscow

VESC in electric bicycle

Postby inteltechnic » 03 Apr 2016, 20:50

Hello!
I am going to use VESC in my e-bike project.
Now i use such controller http://kellycontroller.com/kbs36051x25a ... p-501.html . Its power is OK for me.
But in my new project i need very low weight and small dimensions brushless controller. So, VESC seems to be very good choice for me. I'm not very versed in all the intricacies of electronics. So, i have some questions:
1) Can you please advise- what are the main limitations of VESC to comapre with this Kelly controller in e-bike? (for example,- noise level, torque at low speed,reliability, etc.) The max power of my motor is about 1500W (rated about 500W), the voltage is 22-24V.
2) As i know VESC has good start without hall sensors,right? Are there any difference if i will use hall sensors?
3) As i know - the main problem of standart ESC is that they can burn (when you instantly set throttle from 0 to Max speed). Does VESC have such problem(with my motor power ranges)? How VESC transistors dissipate heat? Does it need any radiator,fan?
4) Does VESC have regulation of phase currents (at low speed)?
5) Are there successful examples of construction of electric bikes with VESC controller? Because i do not see big difference of using VESC in e-bike or longboards.
6) Does VESC have ability to connect e-bike throttle and brake levers?
Thanks!

rew
Posts: 943
Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: VESC in electric bicycle

Postby rew » 04 Apr 2016, 08:28

2) Might require some tuning. I see VESC often "take off" without taking the rotor. Then after 0.12 or 0.45 seconds it does something that works and the motor starts turning.

3) VESC will use current-feedback. It will limit the current to the maximum for the motor or the maximum for the battery, whichever comes first. A controller that directly translates throttle settings to PWM value will induce an enormous current in the motor and burn itself. Hmm. Without current sensors and in BLDC mode, that's probably what happens to other ESCs.

4) ??

5) Working on it.

6) yes.

joe90
Posts: 49
Joined: 15 Dec 2015, 16:52

Re: VESC in electric bicycle

Postby joe90 » 04 Apr 2016, 12:37

4) Yes it does regulate phase current you control torque with your throttle.

I have 2 on me ebike, it work well with only one too.
You will have similar power as the Kelly you have
Will not need much cooling at 25A phase current, fresh air from bike movement should be ok.
Michel Cote
Twin v4.7 + SK3 6374 149KV
Bicycle
2500W peak/unit on 12S

inteltechnic
Posts: 3
Joined: 03 Apr 2016, 20:11
Location: moscow

Re: VESC in electric bicycle

Postby inteltechnic » 04 Apr 2016, 18:10

rew wrote:2) Might require some tuning. I see VESC often "take off" without taking the rotor. Then after 0.12 or 0.45 seconds it does something that

This is without hall sensors, right? With hall sensors all will be ok? So, the only difference (with and without hall sensors) is in that 0.12 or 0.45 seconds time delay? What about torque difference and smoothness of start(with and without hall sensors)?

rew wrote:4) ??

For example from Kelly link http://kellycontroller.com/kbs36051x25a ... p-501.html
• Current multiplication: Take less current from battery, output more current to motor.
So, ussually when bicycle motor start rotation, the pahse current can be much more than battery current. This multiplication works on low speeds, as i understand.
Last edited by inteltechnic on 04 Apr 2016, 20:20, edited 1 time in total.

inteltechnic
Posts: 3
Joined: 03 Apr 2016, 20:11
Location: moscow

Re: VESC in electric bicycle

Postby inteltechnic » 04 Apr 2016, 18:25

joe90 wrote:4) Yes it does regulate phase current you control torque with your throttle.

I have 2 on me ebike, it work well with only one too.

What do you mean? I want to have only 1 motor, 1 VESC with 1 throttle and brake levers :roll: .

joe90 wrote:4) Will not need much cooling at 25A phase current, fresh air from bike movement should be ok.

I want to have closed aluminum case for VESC for protection PCB etc.

joe90
Posts: 49
Joined: 15 Dec 2015, 16:52

Re: VESC in electric bicycle

Postby joe90 » 04 Apr 2016, 18:48

One VESC is ok and work well.
it does current multiplication like kelly.
Michel Cote
Twin v4.7 + SK3 6374 149KV
Bicycle
2500W peak/unit on 12S

jdf
Posts: 1
Joined: 14 Apr 2016, 11:04

Re: VESC in electric bicycle

Postby jdf » 14 Apr 2016, 11:15

I've stupidly blown out my ebike hub motor (q128c) hall sensors, and my roomie had a vesc that was not in use.
(Warning: be careful with heat shrink around the vesc, you might press the battery plus onto the hal sensor pin.. :( )

Have been using a vesc since then in foc mode with a thumb throttle instead of pas, works brilliantly.
phase current capped at 25a, vesc is in a frame bag, so far no thermal problems. I'm on 12s lipo.

dpetrillo
Posts: 25
Joined: 24 Dec 2015, 01:47

Re: VESC in electric bicycle

Postby dpetrillo » 19 Apr 2016, 15:55

I just installed VESC in a 750W hub motor on my bike and have been testing it and I have a few questions for others who have used them in bikes.

I'm running 12s hobby lipo, and a new bafang geared rear hub motor rated for 750 watts that has hall sensors and a temp sensor. I auto detected the parameters using the FOC tab and I'm running it in sensored mode.

1) I get very choppy acceleration at anything above 20a phase current only when starting from a stop. Dead stop is okay, I get smooth static torque available. As soon as the bike starts accelerating a little bit I get quick choppy dropouts. Once a certain speed is reached, its more very smooth acceleration to top speed. Overall it's ridable. I also occasionally get no response for over 5 seconds after cruising at top speed, but it comes back upon resting for a minute. It's not cutting out under load, but after I release the throttle and apply it again, nothing is there.

2) General question about choosing phase current max vs battery max. Clearly the current coming in is what is determining the power output of your motor, as shown in the live data tab. I set a max battery current draw at 20 amps to limit my motor to about 1000w total output for now. I slowly increased the phase amps max until I start to see the battery max being reached during peak acceleration, but had to go all the way up to 55a phase max. This seems high to me, but it's what is necessary in order to get good acceleration, and the motor and fets both do not seem to get hot even when going uphill. Can anyone else post bat and phase max's for their setup?

scienceworks
Posts: 29
Joined: 27 Mar 2016, 16:27

Re: VESC in electric bicycle

Postby scienceworks » 20 Apr 2016, 14:21

hi,

have you tried using the motor in sensorless mode?

from what i remeber the sensored mode is only active up until a certain RPM, which might explain your symptoms.

pf26
Posts: 305
Joined: 28 Mar 2016, 14:37
Location: FR Valence

Re: VESC in electric bicycle

Postby pf26 » 20 Apr 2016, 16:21

@dpetrillo: possibly you have some noise in the hall sensor output causing wrong commutations of VESC. You may want to try to separate the sensors cables from the power cables ?
As for currents, you can set motor currents around 60-80Amps, and battery around 15-20 Amps. Always try less, and increase if not enough.
(obviously try lowest first, and increase if everything stays cool..)
Battery max currents only occur at high speeds.
Regen battery current should be limitted according to your battery (for a 10Ah battery capable of max 1C charging, you should limit with 10Amps regen)


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