I’ve got 3.62 in the repository. Does that work?
3 Likes
Uhh, thats not going to work. Only 3.42/3.48-3.60 is going to work
1 Like
So I was stress testing the Little FOCer in a similar fashion to what you were doing. Unloaded motor. 5uH (killer) at 72V. Was going full throttle with keyboard at 60A and switching directions at max rpm. Got some interesting results.
Nothing died. Most of the time the Little FOCer was fine with it. As I went up in max motor current, I would start to get over-voltage faults. The bus was exceeding 95V. Seems like the back EMF at from the motor at high rpm was coming into play and dumping a bunch of energy into the bus when I suddenly switched directions. My gate drive solution is robust enough to handle it and the MCU alerts on it like it should.
The same thing is probably happening to you with the CFOC2 but the DRV isn’t surviving when it gets the >60V from the back EMF of the motor. I wonder if you lower the battery to 10s if you would stop blowing DRVs.
2 Likes
Ok. You’ll have to snag the firmware(s) from those versions, add the CFOC2 relevant files, make sure the CFOC2 is the enabled hardware, and compile.
1 Like
Alright! I will see what I can do. I will write here if I will have questions.
2 Likes
You’ll also have to use the DRV8301.h and .c files from my code. There’s some unique functions in there that’s not in the vanilla VESC code. Only applicable to CFOC2 v0.9 btw.
2 Likes
Okay. How much will hardware change to v1 btw? Will we be able to do some upgrades to get closer to v1?
3 Likes
Damn I also planned to use Davega (open source) for an escooter project. Didn’t know it won’t work. I mean firmare 3.6 was already working good for me but it’s a pity that the newer version are not compatible.
1 Like
I will try to do it, but I am not sure whether I will succeed. I will post a link here to my google drive with the firmware if I succed.
1 Like
2 Likes
Thst would be great. I know some changes are needed but no idea which ones
1 Like
I can’t believe I missed this post… Here you go haha
3 Likes
It sounds plausible. I actually had a TVS diode on that focer but perhaps it wasn’t enough to keep the voltage down.
10S is not an option since it is a hub motor. I need the speed… would get late to work… at least until we have field weakening in the software 
I thought this issue was related to the DRV reseting the registers. After every such such event, the motor would cog violently. When it happend it was always just after the direction change from reverse to forward.
Perhaps too many of these events with the wrong gate drive setting will break down the DRV eventually and that is what could have happened when the drv decided to fart 
The pin PVDD1 burnt off completely. (power supply pin for gate driver, current shunt amplifier, and SPI communication)
I will do my first road tests tomorrow with the focer in the scooter. Should be fine as long as I keep myself from going full reverse 60kph to full forward
3 Likes
Ahaha amazing.
1 Like
That’s strong evidence to support my theory. Over voltage to the supply. DRV breaks right were supply enters. Smoke released.
Agreed that either way getting the DRV to stop blanking out is required.
1 Like
I was hoping that the TVS diode could aid in such over voltage… Would it be best to put it directly on PVDD1 perhaps?
Or is there to much energy to suppress and this diode is just unnecessary anyway?
1 Like
I’ve looked for TVS diodes but I didn’t have any luck finding ones that clamped at around 60V that didn’t also eat into the working voltage.
1 Like
I was using
P6KE56CA-DIO Diode transil 600W 56V
I simply though it would suppress voltage above 56V.
Looking at the datasheet now. Full clamping voltage 77V wtf!?
Surprising that diode didn’t help 
The diode with full clamping voltage at 59V starts to conduct already between 40-45V
…I see the problem with TVS diode now. One learn something everyday. Thanks 
1 Like
I can conform that running the motor after the DRV loses its mind is a good way to break the DRV. I did this to two CF2 v0.9s before I figured out what was happening. I didn’t have any catastrophic failures, but yours would probably be a slightly different variant on how mine failed. Once you have a fault, make sure you reset your CF2 so the DRV gets the right settings back in its head.
3 Likes
I put two CFOC2’s on my Mtn Board and gave it a test ride today. So far it’s working perfectly.
7 Likes