Sealed Lead Acid Battery Ventilation Requirements

Sealed lead acid (SLA) batteries are the type most commonly used in automobiles, golf carts and other recreational vehicles. SLA batteries are also used as backup power supplies in many situations. Whatever the application, proper ventilation is essential. All sealed lead acid batteries produce hydrogen gas. In the minute quantities that batteries produce, the gas is harmless. However, if hydrogen accumulates due to poor ventilation, it becomes extremely explosive.


Ventilation for sealed lead acid batteries used in vehicles requires no special measures as long as the air around the battery vents to the outside air. In some vehicles (such as large RVs and some military vehicles), SLA batteries may be housed in a battery box. Again, as long as the box has vents to the outside air, no further steps are needed. The key with vehicle batteries is to make sure the battery vent tube is in good condition. The vent tube is connected to the battery and allows gases to escape. Check regularly to ensure the tube is not plugged or blocked.

Power Installations

Sealed lead acid batteries are a common choice for power backup systems, particularly in data-processing centers and similar installations. The batteries should be housed in a separate room with an independent ventilation system. The system should be adequate to change the air in the room using outside air at least twice per hour. The ventilation system should be equipped with an alarm that will sound if the ventilation system fails. Humidity needs to be maintained at 35 to 55 percent and temperature at 72 degrees F plus or minus 9 degrees (22 C plus/minus 5 C). Finally, air drawn into the battery room must be filtered to remove airborne particles that may accumulate on the batteries and cause damaging corrosion. Some sealed lead acid batteries are of the valve-regulated lead acid (VRLA) type and incorporate a gas capture feature that recombines hydrogen with oxygen. VRLA batteries may be used in data-processing rooms because the ventilation required for computer equipment exceeds the minimum requirements for safe operation of the batteries.

Maintenance and Storage

Sealed lead acid batteries are designed to be low maintenance. Nevertheless, you may need to work on one. Work in a well-ventilated area or outside and keep open flames away from the battery. Home storage of sealed lead acid batteries is often useful. Follow the general guidelines that larger installations rely on. Store the battery in a location outside the home, such as a garage. The storage area should vent to the outside, and the home ventilation system should not have an air intake within the storage area. The air humidity needs to be moderate to low, with a temperature range of 63 to 81 degrees F.