When linked to GPS or the Nike+ Sensor, the SportWatch battery can last up to 9 hours. When not recording a run, it can last up to 70 days.
You check the battery level in 3 ways:
Charge the Nike+ SportWatch GPS by simply popping out the USB connector embedded in the watch strap and plugging it into your computer's USB port. The Nike+ SportWatch should fully charge in two hours.
You can also charge your SportWatch battery by plugging it into a non-computer USB charger such as a wall socket adapter or a car charger.
Note: If your SportWatch battery has drained completely, you will need to connect the device to your computer to update to the current time and date.