The 2.5 lbs battery life varies greatly depending on conditions and use. Jetson's battery assists you with paddling and prevents drifting in currents from the take-off point. The more you paddle, the longer the battery will last. The pack has been designed to cover one good surf session, with a good number of waves. Under normal surfing conditions battery should last approximately 60 minutes in the water. Once depleted, it can be replaced with a charged battery pack. If you are one of those water people who want to surf another session you can purchase an additional battery pack.