Proper maintenance is the key to extending the service life of 12V lead-acid batteries for off-grid photovoltaic energy storage. Regularly check the electrolyte level of flooded lead-acid batteries, ensuring it covers the plates and replenish distilled water instead of tap water when insufficient. Gel lead-acid batteries require no liquid replenishment but need a 0.2V lower floating charge voltage to prevent electrolyte drying. In daily use, avoid over-discharge and replenish power regularly during long-term idle periods. Match the parameters of solar controllers to prevent overcharging and high-current impact. Standard maintenance effectively reduces battery bulging and premature aging, maximizing cycle life for long-term outdoor photovoltaic energy storage.