I am having some trouble with my first build and would like some assistance in troubleshooting the issue. My build thread can be located here: http://www.electric-skateboard.builders/t/flatlander-firstbuild-meb-freestyle-deck-fun-box-10-trucks-carvon-v2-5-single-direct-drive-meb-12s2p-liion-pack-vesc/14175
Relevant parts in use: Miami Electric Boards 12s2p 18650 based battery pack Power switch from Miami Electric Boards VESC from Carvon running firmware 2.18 Carvon v2.5 hub motor
Symptoms: When I accelerate hard, the motor will no longer be driven and I will coast. Battery voltage reading in VESC Connect app will drop from ~42V down to 12.7V and dropping. If I time it correctly and apply some brake, battery will jump back to previous 42V+ level and board will remain powered on. Sometimes, however, the board shuts down entirely even though the power switch is turned on. When the board completely powers down, I also get a FAULT_CODE_LOW_VO (I assume it’s “voltage” and just being truncated by the display). Also, the duty cycle in the VESC Connect app will jump from wherever I was (usually about 50-55%) up to 95% when this happens.
What I have done to troubleshoot so far: I have tweaked many many settings on the VESC, most of which seem to make the problem worse. I have disabled FOC and gone back to using BLDC to see if this caused the issue. In doing so, I had much trouble with performing motor detection, which often forced the problem to occur during detection. I performed a “read default configuration” to get back to sane values and was able to get the motor detected properly. Every time I try to do detection, the first attempt fails inside of BLDC tool, but the second try gives me useable values.
Because I was experiencing issues with the power switch, I wired the battery directly to the VESC, and still experienced the cutouts of throttle. I was, however, able to get the motor back online by applying brake to “jumpstart” the VESC back up.
What I plan to do next: I will be taking detailed screenshots of my VESC settings and I also saw some great data logging that others have posted in their troubleshooting threads using metr, so I will be playing with that to gather some data. Please let me know what information would be helpful to diagnose this issue. Also, I think I will be duct taping an action camera to the underside of the board to watch the voltage display on the battery pack to see if the voltage is actually sagging when the motor cuts out, helping me to pinpoint the issue to the battery pack or eliminate it as a suspect.
Thanks in advance for your help, folks!