VESC includes the following settings that relate to battery voltage / your battery pack.
The below advice is specifically for Lithium Ion battery packs (pretty much 99% of packs used in Onewheels if we ignore the OW+)
Motor - General - Advanced
Min/Max voltage: this is the min/max voltage the controller can handle - DO NOT TOUCH!
Exception: the UBox80 has them set too low by default, increase the max to the highest value it permits (go up in increments of 1-2V)
Motor - General - Voltage
CAREFUL! The wizard inserts much higher numbers here, targeting ESK8/EBike use. For onewheels this means a nosedive! We intentionally keep our cutoffs very low to let tiltbacks prevent us from ever reaching those levels
Cutoff Start / Cutoff End - set this to 2.7V/2.5V * series cellcount
Float Package - Specs
High Voltage Tiltback - set this to 4.3V * series cell count
Low Voltage Tiltback - set this to 3.0V * series cell count
If you forget to adjust these when upgrading to a higher voltage battery you will likely feel high voltage tiltback as soon as you step on your board!
Motor - Additional Info
VESC lets you enter details about your battery here mainly for capacity/range estimates. The settings here have zero impact on ride behavior!
Cell Type: we all normally choose Li-Ion - not sure why FM calls theirs NMC batteries, all XR/Pint/PintX/GT packs are Li-Ion too…
Series Count: Pint/PintX/XR packs are always 15, GT is 18, for more examples, see:
FAQ - Batteries
Why do we recommend the numbers this way?
Ultimately, in a self-balancing vehicle, it is best practice to prioritize rider safety over board/battery protection when possible and sensible. If we just let VESC cutoff the motor mid-ride with no warning, it is a guaranteed nosedive. Therefore, to ensure the rider gets proper warning before any extreme action like motor cutoff occurs, any cutoffs should be adjusted from their defaults to be below the Low Voltage Tiltback threshold, which is recommended to be at the equivalent of 3.0V per cell.
From there, you can determine how low you’re willing to let your battery drop to, and how much you want to prioritize rider safety vs. battery health once they have been warned by LV Tiltback. The general recommendation, as stated earlier in this article, is a Cutoff Start and End representing 2.7V per cell and 2.5V per cell respectively. This works to prevent the risk of the pack sagging too low and cells being damaged. Some others may prefer more headroom for rider safety, such as with Mario’s recommendations of Cutoff Start and End representing 2.3V per cell and 2.0V per cell respectively. This lets the cells sag lower, with the idea being that when hitting that mark under load, they will generally rise back up to 2.5V per cell when idle, but it does have higher risk for battery health and longevity.
Regardless, how you configure these cutoffs and prioritize rider safety vs. battery health is defining the extreme case of what happens when you push through Low Voltage Tiltback. Ultimately, to avoid risk to yourself and to your battery, Low Voltage Tiltback should be respected, and you should stop riding once you hit that threshold!
Mario’s perspective (from a FB comment, June 29th, 2023):
“In my opinion, 54v is still a bit high for 20s. That’s 2.7v per cell, and it’s a quick drop to 2.7v from 3v, especially if a rider pushes into the tiltback.
I set my cutoff start at 2.3v per cell start, and 2.0v per cell end.
Any time I’ve ever pushed it that far, and the load is removed from the pack, the voltages rise up above 2.5v.”
Dado’s perspective
I suggest you guys do not follow Mario’s example in this instance - 2.7/2.5 should provide plenty of margin still with the newer cells. If you want more margin (e.g. if you have a weak stock XR or Pint battery) you should increase tiltback voltage to 3.2 instead.
Once your cells are below 3.2V you will start getting low voltage tiltback as soon as you do anything remotely torquey, like going over bumps or small hills. So I personally find it very hard to even reach 3.0V resting voltage and I consider boards below 3.2V to be unsafe to ride…
CAUTION - Floatwheel Users!
The Floatwheel BMS will cut off at 2.7V per cell anyway (so setting the cutoffs any lower than 54V makes absolutely no difference for you) Make sure you got your tiltback well configured to never get close to the BMS cutoff voltage. I recommend you just set the VESC voltage cutoffs to 54V/50V so they don’t cause additional issues but don’t expect them to ever kick in