Why does a twin charger only charge one battery at a time?

Trimble Dual Slot Charger for RTS and MT1000GPS Batteries

NEW TRIMLE DUAL Slots Charger for Trimble R10 S8 GPS, Total Station

trimble dual slot battery charger manual The Dual-Slot Battery Charger with Power Supply for Trimble GNSS Receiver can be used with a Trimble Total Station or MT1000 It comes with two slots and

gudang slot 138 New Trimble Dual Slot Charger, Trimble 2 Slot Battery Charger for Trimble GPS, Total Station S8 R10, R12, 53018010, Find Details and Price about Trimble