SLA batteries naturally discharge over time. If it is not charged periodically, the battery’s full capacity may not be reached again.
SLA batteries self-discharge at a rate of around 3% a month. We recommend checking on and charging SLA batteries at least every two months.
Never store an SLA battery longer than six months without recharging it. Always store batteries in a cool, dry place. Generally, a battery can last 6 months to 1 year on a shelf with mild temperatures.