Several factors affect the life of rechargeable batteries, but the most significant is correct battery charging. Other factors include the type and quality of the battery, its discharge rate and the environment in which it is used. For prolonged battery life, always follow the manufacturer's charging directions, and always properly store a battery not in use. With correct treatment, rechargeable batteries should last several years.
Always charge a new battery before placing it into service. An improper or weak initial charge can shorten its life significantly. Some rechargeable batteries can withstand overcharging, but others will not. Some chargers will automatically shut off when the battery is charged. You can purchase some rechargeable batteries as a set with a charger included. Others must be purchased separately. But always use the appropriate charger for your battery, and follow the guidelines, not only for the battery, but also for the charger. Never try to charge a battery not designated "rechargeable."
Type and Application
Rechargeable batteries come in all sizes, ranging from the AAAs in your TV remote control to the batteries that back up an entire hospital in a power outage and tend to be as large as a washing machine. Types include alkaline rechargeable (not to be confused with plain alkaline), nickel cadmium, nickel metal hydride, lithium ion and lead acid. But no single criterion provides enough information to determine which rechargeable battery would be best for the longest life. Some useful suggestions can be found under "What's the Best Battery" at http://www.batteryuniversity.com/partone-3.htm
The rate at which a battery operates the equipment in which it is installed is called its discharge rate. Using a battery outside its recommend discharge rate can shorten its expected life. So always use a battery that was designed for your equipment. Also, some batteries' lives will be shortened if they are discharged beyond a certain point. Never use a battery past this point. And never short the output terminals because this can also shorten battery life.
Any rechargeable battery will have a longer life if it is operated only at room temperature. Dampness and humidity can also shorten the live of a rechargeable battery. If you need a rechargeable battery for use in extreme weather, check to see which battery is best for your specific application.
Shelf life for most rechargeable batteries is longer if they are properly charged before being stored, and best if stored at cool room temperature. New lead-acid batteries are an exception to this rule, but only if the acid has not yet been added. Many new lead acid batteries, such as some car batteries, have the acid added when they are installed and therefore have a much longer shelf life.