The Wireless Hand Controller contains a USB rechargeable battery requiring about 2 hours to fully charge the battery from a standard USB charger or USB PC port. Once charged, the hand controller goes into an 'always ready' low power mode. In this mode, a fully charged battery will last for approximately 170 hours and instantly wakes up and turns on when a button is pressed.
Best to determine the level of battery charge remaining before a race event starts, To do this, press and hold the black button, press and release the white button, then release the black button. The battery level is measured by the hand controller and sent to all the safety lights.
The safety lights display green if 100% to 50% of charge remains, display yellow if 50% to 20% charge remains, and display red if 20% to 0% charge remains. Lets say yellow displays and taking the worst case scenario, 20% battery charge remains. 170 hours x 20% = 34 hours of charge remains, of course, a busy track requiring a lot of safety light use will be less than the full 34 hours.
In the event you completely forgot to test or charge the Wireless Hand Controller, plug it into the charger and operate it while charging. Charging for 15 minute will provide about 10 to 14 hours of use as a quick solution.