What is the ideal operating temperature for VRLA batteries?

The chemical reactions inside a lead-acid battery speed up with temperature. Above 25°C, plate corrosion and water loss increase. A general rule of thumb is that every rise of about 10°C roughly halves battery life. So a battery that would last several years in an air-conditioned room may need replacing much sooner in a hot cupboard.

Cold works differently: it does not wear the battery as much, but it temporarily reduces the available capacity and therefore the UPS backup time. At very low temperatures a discharged battery can even freeze.

Under normal conditions, UPS batteries are usually replaced every 3–5 years, depending on temperature and use, and temperature is the factor that matters most.

Practical tip: place the UPS away from radiators, direct sunlight and closed, unventilated cabinets, and leave free space around the vents. In server rooms and electricalGlossary · Power qualityNoise (Electrical)Unwanted high-frequency disturbances on the supply voltage, e.g. from motors or power supplies, which UPS systems and line conditioners filter out. rooms, measure the temperature close to the batteries, not at the other end of the room.