A multiple-battery charging system for enabling a vehicle with an internal-combustion engine or hybrid engine to be equipped with a plurality of electric storage batteries. The multiple-battery charging system automatically connects batteries to load, at times alternatingly and at times in parallel. All batteries are charged, together or seriatim, and maintained in a charged state, by a single conventional charging source (alternator) with which the vehicle is equipped. In abnormal operating circumstances, such as when one or more batteries are defective or shorted, or the alternator is defective, the multiple-battery charging system prevents an operator from depleting a battery to the point where necessary peripheral equipment, such as a wheelchair lift, can no longer be operated.