Hello,
I need some help, as my trampa vesc 6 plus (HW60, FW5.1) is currently unable to deliver power.
My setup: ebike, 12s4p liion battery, 530kV Assault 700 motor. Freewheel, motor brake is off.
VESC setup: FOC drive, ADC throttle current input. Max motor amp 110A set, OC limit at 140A. Mosfet temp limit start lowered to 60C, ends at 85C to counter the higher allowed currents. Trampa silicone cover for increased water safety.
Previous known problems: seldom overcurrent fault at full throttle input at higher speeds (=> high input current), but I was able to live with that.
Current problem: I got caught up in a storm (been in that twice before without a problem) while I was doing a long uphill ride. After that there was like 2km of straight with only slight rain and then a bit steeper uphill road section again with almost no rain. Was riding with around 60-70% throttle. All of a sudden the motor stopped. After restart (1sec) the motor spun up a little but stopped again, and again. After some tries it went silent. Afterwards I have disconnected the power, waited a bit, then the same weak spun for ca 0,5s then stopped again. I have disconnected the battery till I got home, where I have checked what the VESC tool can see.
Battery OK.
Motor: not completely sure, but seems to be ok. I ran a new motor detection test with vesc tool, and read quite similar results as prevoiusly, however slightly higher (10%) motor resistance. Sampled BEMF signal also seemed nice when I first checked it later that day:
Then giving more throttle it showed the same problem as during that slope. It seems like it kinda shorts the battery after a fault, resulting in sudden loss of voltage which causes it to even shut off - connection lost with PC. Here's the log what the tool created: https://www.dropbox.com/s/itprfmzqu13xt71/2020-07-12_15-03-48.csv?dl=0 sorry it's very big, but my excel cant really open it normally (voltage shown as date..) so I have uploaded the original. The worth part is at the end. At row 35329 battery level goes to 0 and after couples of samples the voltage goes down gradually. At the end fault code 2 and 3 logged.
As I have played a bit with it, it started to show the following weird BEMF. It was taken at 61% duty, but it shows very similar values no matter what the rpm is.
What could be the possible cause for the symptoms? What could be the faulty element?
I have not yet opened it. Benjamin, Frank, do you have any suggestions?
Unfortunately I start to believe it needs HW repair.
Thank you.
After some further in depth observations (taking everything apart) I have concluded:
- VESC 6 MKIII with silicone cover can protect well against even bigger rains, however is not providing perfect sealing. Some sand particles were slowly getting inside, but it turned out after some drying it is working well.
- motor held up well too even on sustained high speed high elevataion routes, FOC definately helps reducing waste heat. Current limit, and mosfet temp limits help a lot.
- battery power contacts were the culcprit: one of them melted the housing plastic which further worsened the contact from battery to bike contact. After cleaning and readjusting the small nickel plates to increase the contact area-force it works like a charm now. While taking apart the battery I recognised that 1 liion cell had its spot weld lost. Most probably cell arrangement is not perfect and due to this it could not cope with heat expansion, vibration.