UPS battery series

• Does the UPS need to have a load on it to charge its batteries?[Dec-31-2015]
• How is battery runtime affected if I reduce the load on the UPS?[Dec-31-2015]
• If I add more batteries to a UPS, can I add more load?[Dec-31-2015]
• What is the average lifespan of UPS batteries?[Dec-31-2015]
• My UPS has been in storage for more than a year. Are the batteries still good?[Dec-31-2015]
• How can I ensure that my UPS batteries are maintained and serviced properly?[Dec-31-2015]