You can turn off the fan by activating silent mode.
Please note that without the fan running, the heat generated from charging/discharging needs longer to dissipate and the Omni20 might enter 'Overheating Protection'.
1. Double tap the Power Button to enter the menu.
2. Scroll down the menu and enter 'Silent Mode'.
3. Choose 'On' to deactivate the fan and exit the menu.
4. On the OLED screen you can find the 'Silent Mode' icon.