VESC Cause of Failure?

ESK8 Electronics
1

Hello everyone, this is my first time posting on here, so my apologies if I fail to provide some critical information up front. I’ll do my best to describe my issue, and appreciate any help I can get.

I’m running the following setup

Hardware:

2x 6374 170kv motors, 10S 20Amp BMS (in-line to charge, bypass to discharge), 10S2p battery, XT90 Loop key, GOFOC DV6 VESC, VX1 Remote with splitter (for dual motor vesc), 20T/36T pulley ratio,

A few motor VESC Settings: Motor Current Max: 60A. Motor Current Brake: -60A. Absolute Maximum Motor Current: 150A. Battery Current Max: 99A. Battery Current Max Regen: -60A.

Basically I was on my first day of testing my setup out, I had taken it out for about 5min and then adjusted some of the remote settings and then took it out for another 5min. Everything was operating normally, until it suddenly quit on me. I wasn’t going up a hill or down, I was going fairly slow and I wasn’t necessarily breaking very hard and it just shut down. I went to check on the VESC and I noticed that the blue lights were no longer on, but the red light to my remote receiver was on but appeared to be very dim. The VESC was also very hot. I check my battery output and it was reading about 38v. There was no longer any signal to the motors and when I attempted to connect it to my computer there was no connection to be made. Lastly, I checked all the pins on the VESC for motor and remote input and they were all reading about 2.5v, where I except them to read 5v.

MakerX was kind enough to let me return it for refurb or exchange, so waiting on that now, but I don’t want to make the same mistake twice.

I do wonder if one of my cells is on the fritz. I’ve used the same battery on a different setup, where BMS was inline on discharge, and it would often shut down power. However on this setup, my BMS is not inline on discharge. But a bad cell or two wouldn’t cause an overvoltage that would fry my VESC, right? I thought the VESC had mitigations for that within itself.

Basically, I’m wondering if there is anything that sticks out in my setup that could be remedied. Otherwise, I’ll assume it was a bad VESC. Anyways, thanks in advance for any help!

2

This was needed to be changed to what your battery can produce divided by 2. The regen could be higher, but this was probably the reason. You also had to make sure it’s written on the slave side as well (the divided by 2 part).

Do you know what battery type/brand you had?

This is unnecessary for the dv6. It controls both slave and master with just one side.

It can. However, this was probably a setting failure. But to be sure, you would need to check each individual cell to see if any are faulty.

3

Thank you for the reply @LeonCamero.

I’ll definitely take a look at my max current and regen. I have the mboard 10s2p:

And yeah, I’ve been hesitating to pull my battery completely apart to measure the cell’s individually. I don’t have the equipment currently to put it back together (spot welder, etc…)

4

If it’s this exact pack, it would be way lower than what you have as your battery current max and regen.

It would be 15A per side and >-20 per side.

And since it’s 30q, you may need to check since those batteries has a history unfortunately. All you need is a large battery heat shrink, a heat gun and a multimeter. You’re only checking if the cells are normal or not.

Taking it apart is when youre replacing them, which not many has the tools to do so.

5

Thanks @LeonCamero

Okay, sounds like I definitely need to update my current values and check my cells. How did you come up with 15A per side (30A total)?

Yes, it’s that same battery back, but I’ve switched out the BMS.

I was under the understanding that cells needed to be electrically isolated from neighboring cells (remove nickel strips) in order to get useful voltage, charge and discharge capacity values. Is that not the case?

Thanks!

6

I’m not sure. I’ve only learned from those who do make them. So i would just go with that.

Samsung 30qs are rated 15A discharge. 10s2p is basically 15A × 2p (parallel increases current) and You’ll get max output of that pack.

You must know the battery brand and type for a much accurate calculation.