Abs over current fault while full throttle, 8s, directfet VESC

ESK8 Electronics
1

Hi there! Here is my first post about my board. I have been browsing the forum for 3 years. Now I’ve decided to create an account, cause I cannot find answer to my problem. Recently I’ve finished build of my mountain like longboard (well… some Polish roads are terrible :wink: ). This is my second attempt - first one was almost the same (one year ago), but with smaller wheels.

TL;DR: ABS OVER CURRENT error at full throttle, asymmetrical power cables from batteries - is that a problem?

Long story: Yesterday I made a test drive. I was slowly spinning up longboard and when I was at full throttle, the engine stopped (and I fell off the skateboard). It happened only once, since I was afraid of falling again :worried: I had something around 24 kmph (15mph).

I connected the VESC to the computer and in the terminal I had only one error:

Fault            : FAULT_CODE_ABS_OVER_CURRENT
Current          : 148.0
Current filtered : 132.6
Voltage          : 29.44
Duty             : 0.005
RPM              : 27178.5
Tacho            : 1053289
Cycles running   : 623544
TIM duty         : 265
TIM val samp     : 132
TIM current samp : 26714
TIM top          : 53164
Comm step        : 1
Temperature      : 53.86

I have tested the motor with multimeter, battery connection, VESC (visual contition) etc. and everything seems fine. In the first build I had exactly the same problem, but in Turnigy 4.10 VESC. After switching to directFET VESC problem still occur. Both VESC’s were send to manufacturer and they passed their tests.

Today I gave another try and the same problem appeared on around 85% of throttle … No DRV errors encountered.

Some ideas: Maybe someone have an idea what is wrong with this build. I suspect the battery problem but I cannot find any information about different lengths of a cables. In my configuration positive one has 38 cm (14.9 inch) AWG10 and negative one has 63 cm (25.6 inch) AWG8. I have spent a lot of time on forum to find similar posts, but most of them were connected with VESC hardware problem.

Another suspect: motor. I tried detection again and at the first time value of BEMF Coupling was around 900, but now measurement is around 760. Problem still occurs.

Setup:

5065 Outruner 270KV (measured 240KV) 1665W in BLDC mode
DirectFET VESC 4.12
8s8p LiIon battery (LG MH1)
Gear ratio 15 / 56 HTD-5M

Pictures of board:

IMG_2039

IMG_2041

Pictures of VESC Tool:

53

57

Thank you for reading this post and I’m counting for your help! :smile:

2

I think your question should become the template for all future questions. Really nice info you provided :smiley:

The long battery leads could very well be the reason for the issue. Longer leads = higher inductance = more for the capacitors to deal with, which could lead to FAULT_CODE_ABS_OVER_CURRENT.

I would try and shorten them and see if the problem persists. You could also try bringing your motor max current down a bit (closer inline with battery max current) but that would lower your acceleration.

3

Thank you. I wanted to make nice and clear post with all required info and observation :wink:

Yea, I would like to test it out, but the main problem is configuration of the batteries. Negative cord is at the end of enclosure, and positive is at beginning.

I realized right now, that my friend have some Li-Ion batteries to another project. I will borrow them, connect in 8S1P and check if that fixes a problem. I need to prepare myself to fall down. That’s awful thought.

Going to try this too, even if present acceleration is very crappy :frowning: For real, this engine make noises like it going to die (or like small electric cars for kids :joy: ). I know it’s cause of using BLDC :wink:

4

I lowered value for motor down to 40 Amps. I gave it a try and surprisingly no error during test around house. I slowly increased speed to around 20kmph (12.4mph) and then kick throttle to full value for few seconds. Tried dozen times - still no faults and acceleration is smooth. Going to check it at longer trip soon, but now my leg need to rest after falling off a deck :expressionless:

1 Like
5

Interesting result I had a dule set up at 35 motor 25 battery had the same issue had a motor issue and reset it up as single drive 55 battery 55 motor not had a fault since. I put it down to a faulty motor but now I’m wondering if it was both.

6

I think the motor is broken. My friend was driving and it cogged while was accelerating slowly to full throttle without throwing any faults … Need to buy sensored one because I don’t want to make an accident.