Killed both CAN chips but how?

So what happened:

Had a board sitting on the shelf for half of a year. I took everything apart and reassembled it new, checked battery and rewired most of the connections. Everything was ready, but i didn´t connect the motors to the vescs (4.12). To test the new lights i switched on the BMS to power the vescs which feed the leds through the receiver. Both Vescs are powered on the same time and are connected over CAN. Plopp! Bit of magic smoke and no LEDs on on both Vescs. Reciever was still powered and Lights worked like they should. After i closed my WTF-face a minute later i checked the Can cable. Everything good! Nothing loose and not a bad contact!

HOW did i kill them? Had a propper connection, both vescs were powered and firmware was configured the right way about half a year ago and can worked back then!

Do you have a photo of the wiring?

nah, i already took it apart again yesterday. Wires were all good, tested everything. Pretty sure it´s a vesc kind of problem, but im not sure why

2 or 4 wire can cable?

two wires. Is a 4 wires-Can cable even a thing on the 4.12 to connect two? I don´t think so without killing it :face_with_monocle:

4 wires will mostly fry your vesc, because of a ground loop

Yah, that´s why i´m wondering where @bimmer has had 4 wires before.

If he´s just wondering if im stupid enough to did a 4 wire connection - nah mate, can´t be so drunk to do that over 2 years of working with vescs :wink:

@JohnnyMeduse any idea how thats possible?

So did you kill the CAN chips or the 3V3 regulator, if no leds are lighting up?

Good question, last time i had something like this, the Can chip died. Do you know how to check if its the regulator?

Both ESCs connected to the same battery I guess, one switch.

Yes for sure! (Is anyone running dual on two different batteries?)

CAN on HW 4 can handle ±12V only, while HW6 can handle ±60V. This is why HW 4 needs to be powered up at the same time. If for some reason there was a voltage difference above 12V, they would have blown because of that. And to me that sounds the most plausible explanation. The reason for the voltage difference has to be somewhere in the system or on one ESC. It is always a good idea to test things on 11.1 V (3S) if you have a 3S to hands to avoid such issues.

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(Is anyone running dual on two different batteries?)

YES we are.

can anyone confirm this?

i am currently setting up 2 esk8 VESC 1.1 and they’re HW 4.12 afaik.

@esk8 maybe you can give us some answers


i never heard of this problem but this scares me of using CAN for 2 VESC on the same battery

good to know. The thing is, the setup ran fine half a year ago, but now poof…

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I know I am repeating myself but does anybody have a link or a quick explanation on best practices when connecting VESCs 4 and CAN bus? Especially when setting up the VESCs.

Whats important? Which order?

Threads like these give me goosebumps.

I get that both vescs need to be on the same power source and connected simultaneously. Is that all? CAN bus connected from the beginning?

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yeah, i want this too. still afraid to connect the VESC together via CAN.

Yes, CAN connected, simultaneous start-up. At setup 3s is always a good idea and CAN save some $$.

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This is how you should do it. Y-PPM causes ground loops, which can kill your voltage regulators, since they will always fight against each other. CAN is the way to go and should work just fine.