On a 2.5-hour charge from the 2.8A multi-voltage charger, Profoto's Lithium-Ion Battery for B1 and B1X AirTTL Flash Heads will provide you with up to 325 full-power flashes and thousands of low-power flashes. That time is reduced to one and a half hours by the 4.5A quick charger. You can keep an eye on the charging progress thanks to fuel-gauge-like LEDs on the battery and both of the optional chargers.