The battery is the most important part of a phone and everyone has a question that how to get maximum backup from battery. Its become a big headache if your battery not giving you proper backup. Phone batteries do need to be initialized properly to ensure a full life and best backup. New batteries should always be fully charged before their first use to obtain maximum capacity.
Mostly old batteries are based on Nickel, like nickel cadmium batteries, and they should be charged for a minimum of 16 hours initially and should be run through 2-4 full charge/full discharge cycles.
The mostly new batteries are lithium ion batteries and they required to be charged for about 5-6 hours, even if the phone says that the battery is full, it should be ignored as it may not be accurate unless the battery has been initialized. Lithium ion batteries should never fully discharge as their life is shortened every they are fully discharged. Instead they should be charged when the battery meter shows that there is only one bar left.
Almost all cell phones these days come with Lithium-ion batteries, while older ones used to come with nickel-based batteries. To know this you can read the label on the back of the battery or the technical specifications that are present in the manual to find out which kind of battery is present in the phone.
A well known problem with batteries is "memory effect" which only found on Lithium-ion batteries. NiCd or NiMH do not generally suffer from the memory effect. If you end up charging the battery partially too many times, eventually the battery tends to "forget" that it has the ability to charge itself fully. A nickel-based battery which succumbs to the memory effect can be reconditioned, by completely discharging, and then completely recharging the battery. A good way to ensure optimum life for nickel-battery cell-phones is to discharge them completely after a period of two to three weeks. You should also use the charger that is rated for your battery, and should discontinue the use of a charger that regularly heating the battery.
Battery Should Keep in Cool: If the battery not in use for long durations of time, you should put the battery in the freezer or fridge. The battery will last longest when used near room temperature, and it'll reduces battery life if exposure to high temperatures. You should avoid leaving phone in a hot car or in direct sunlight.
If there's no use of your phone battery for a while, you should disconnect it from the phone and store it in a cool place. For this refrigerator is good choice, and it should also be kept away from metal objects to reduce chances of oxidation. The battery is not exposed to moisture by keeping it in an airtight container or bag. Lithium-ion batteries are not designed to operate at refrigerated temperatures, so after removing from the fridge keep the battery outside the refrigerator for at least an hour before using it again so that it comes down to room temperature. Avoid storing Lithium-ion batteries at low voltage. Lithium ion batteries also tend to oxidize least when they are stored at about 40% charge.
The contacts of battery tend to accumulate dirt and oxidation on the contact points after a period. You need to clean contacts with a cotton swab and rubbing alcohol to efficiency of energy transfer to a maximum. In addition to that, if the contacts points are made of two different metals, such as gold or tin, accelerated corrosion can happen which is known as "galvanic or bi-metallic" oxidation. Removing this type corrosion from the contacts may sometimes require the use of solvents, such as acetone or nail polish remover.
If you follow above steps and precautions, you can get the maximum backup from your battery.