Age: (All sealed lead acid batteries eventually exceed there life expectency.) A SLA (Sealed Lead Acid) battery can generally sit on a shelf at room temperature with no charging for up to a year when at full capacity, but is not recommended. Sealed Lead Acid batteries should be charged at least every 6 – 9 months.
A valve regulated lead acid (VRLA) battery is also known as sealed lead–acid (SLA) battery is a type of lead-acid battery. In this type of battery, the electrolyte that does not flood the battery but it’s rather absorbed in a plate separator or silicon is added to form a gel.
Sealed Lead Acid batteries should be charged at least every 6 – 9 months. A sealed lead acid battery generally discharges 3% every month. If a SLA battery is allowed to discharge to a certain point, you may end up with sulfation and render your battery useless, never getting the intended life span out of the battery.
VRLA batteries are supplied fully charged, storage time is limited to a maximum of 6 months without recharge. If batteries are to be stored for longer periods, its recommended they be charged fully after every 6 months. The self-discharge of a fully charged VRLA battery is around 2% per month at 77°F (25°C).
If you are going to store sealed lead acid batteries on a shelf without charging them, it is recommended you store the batteries at 50 degrees Fahrenheit/ 10 degrees Celsius or less. When storing sealed lead acid batteries for long periods, it is recommended that you top charge the batteries periodically.
Service life is strongly related to the working conditions of the battery. Factors affecting the service life are: The operation of valve regulated lead-acid batteries on float at temperatures higher than 20°C reduces the battery life expectancy, with 50% life reduction per 10°C constant increase of the temperature.