Epson OT-CH20II (391): Multiple battery charger for P20IIMultiple battery charger Charge up to four Epson OT BY20 batteries simultaneously. Fully charge up to four Epson OT BY20 Li ion cells in less than 3 hours at normal temperatures (between 10 to 40). Inserting and removing batteries, is fast and easy, and the charger features an LED indicator that shows charging status. An AC adapter is incuded.