The Sony BC-SAD1 Battery Charger is an efficient way to charge two high-capacity NP-SA100 batteries simultaneously or independently, assuring you have ample power for use at events or in applications that require continuous operation over extended periods of time. The BC-ZD1 can fully charge two batteries in 115 minutes, a single battery in 85 minutes, or a single battery to an 80% charge in 55 minutes.