What is duty cycle and why do we care?
Note: If you want to know all the details on duty cycle and how exactly it works and what it does - google it. This is not the purpose of this page
Alright - so here it is for us Onewheelers: Think of duty cycle as a measure of a motor’s capacity to make a motor spin faster.
At 100 percent duty cycle you’re at max speed. As you accelerate your duty cycle increases until you hit max duty (technically 95% is usually the safe maximum a controller can handle).
Another Note: there’s more nuance to it at very low speeds, but if you remember just the above statements then you will be fine!
Your max speed (aka 95% duty cycle) is pretty much directly proportional to your pack voltage.
On a fully charged Onewheel with stock 15s (63V) battery 95% Duty Cycle will be around 20mph.
When the battery is empty 95% Duty Cycle will be around 16mph.
see note about field weakening down below
Using a 20s aka 84V battery 95% duty will be 30 percent higher, due to the 30 percent higher voltage.
Why does duty cycle fluctuate so much?
In short: Voltage sag
When you accelerate you use more amps. Amps drawn from the battery cause the voltage to sag, i.e. to decrease temporarily. So the consequence is that you will hit 95% duty cycle sooner.
If you’re cruising downhill your battery will not sag, or sag much less, so your speed at the same duty cycle will be much higher.
Note on Field WeakeningIt is possible to extend the top speed by adding field weakening current. With 30 Amps of field weakening speed at 95% duty cycle will be another 30-50% higher
See other pages here for more details on field weakening
What happens when I hit max duty cycle?Once you're at 95% duty cycle that board is no longer able to accelerate you further. The controller is able to safely maintain that speed at 95% duty but it may still cause you to nosedive because balancing requires the ability to accelerate/decelerate the motor...
In short: try to remain below 95% duty at all times