Voltage cut off under load

ESK8 Electronics
1

Looked around on the forums for help but I could find anything to help.

190kv 10s4p Vesc 4.12

At full charge and up to 3/4ths throttle everything is fine. When I hit full throttle sometimes the vesc cuts out, I have to break a little then I can continue riding. When the battery starts getting lower full throttle doesn’t seem to bother it as much. I can ride around all day with no issues if don’t go full throttle.

The following faults were registered since start:

Fault : FAULT_CODE_UNDER_VOLTAGE

Current : -0.2

Current filtered : -0.1

Voltage : 8.00

Duty : 0.950

RPM : 10722.7

Tacho : 107023

Cycles running : 0

TIM duty : 4560

TIM val samp : 1200

TIM current samp : 3600

TIM top : 4800

Comm step : 3

Temperature : 56.14

Fault : FAULT_CODE_UNDER_VOLTAGE

Current : 0.6

Current filtered : 0.1

Voltage : 8.00

Duty : 0.950

RPM : 10789.4

Tacho : 120744

Cycles running : 0

TIM duty : 4560

TIM val samp : 1200

TIM current samp : 3600

TIM top : 4800

Comm step : 2

Temperature : 55.61

Fault : FAULT_CODE_UNDER_VOLTAGE

Current : 0.2

Current filtered : -0.2

Voltage : 8.00

Duty : 0.950

RPM : 10663.5

Tacho : 123542

Cycles running : 0

TIM duty : 4560

TIM val samp : 1200

TIM current samp : 3600

TIM top : 4800

Comm step : 4

Temperature : 55.53 vesc settings Motor current 70a Max break. -60a Absolute 130a Battery 50/-50 Voltage cut off 34-31

2

This exact thing happens when I was testing my unbalanced battery. It was due to the BMS freaking out and cutting off load. Are you discharging through your BMS?

3

Yes I am, the battery was balanced when I got it two days ago

4

Cell sag will do that.

5

Is it common for it to sag that bad to cut off the vesc? And if so is there a way I set some setting combat that?

6

Cell sag does NOT sag that low. This is most likely BMS cutting off due to overcurrent. What pack do you have? @Jordan12

7

Another possibility is fake cells not being able to handle the amperage and sagging

1 Like
8

Lol a nice beauty from China… I’m saving up for a nice 30Q I promise

9

yea… you’re probably gonna want to limit the current on the vesc to whatever the pack can support.

10

The battery and motor current?

11

And any recommendations?

12

Just battery current. Also your battery min is WAYYYY too high. What pack do you have 10s?p and what cells?

EDIT: nvm i see it’s 10s4p, but would still like to know the cells. 50 amps should be fine for it unless they’re fake cells, though they might have included a shitty BMS

13

I’m honestly not sure why I left it that high. And I don’t know I’ve been trying to ask them but they just keep saying “it’s a 18650 cell” … thanks

14

I did order a supower bms to replace this one, had issues with a 6s2p battery that wouldn’t fully charge

15

yea… my guess is BMS cutoff, you could bypass discharge, but without knowing the cells, it can be risky

16

I’ll start with lowering the battery amps see if that helps. Resent them a message, probably won’t hear anything back the worst people to contact.

17

single motor right? I’d use 30a battery max as a conservative setting.

18

Yes single motor

Will do. Thanks for all yalls replies

19

If you are dead set on not changing battery packs for the moment you might be able to drop some rather large caps in parallel with your pack. I know that the vesc’s have their own but some ultra caps might be enough to make the sudden current draw a little less harsh.

I would say bypass the BMS and just ride with a fire extinguisher if you just want all the current though. :rofl:

20

@JakeSkate Got a link on how that works? I’d like to learn more about that stuff. Lowering the current pull from the battery seemed to help. I didn’t fully get on it yet.