The Automated External Defibrillator (AED) is a portable medical device designed to deliver an electrical shock to a person experiencing sudden cardiac arrest. This device is often found in airports, schools, and workplaces as part of public safety readiness. The AED’s ability to function correctly depends entirely on its power source. Without an operational battery, this life-saving equipment is ineffective. Maintaining battery functionality is the most important factor in ensuring the device is ready to deploy.
Understanding Standard AED Battery Lifespan
Manufacturers design AED batteries, typically non-rechargeable lithium models, with two distinct capacities. The first is the standby life, which is the total time the battery remains installed and ready for use without activation. This period commonly ranges from two to five years, though some models may offer up to seven years under optimal storage conditions.
The second capacity is the operational capacity, which defines the amount of work the battery can perform once the AED is turned on. This is measured by the total number of shocks the device can deliver or the number of hours it can continuously monitor a patient. A common operational capacity might be 200 high-energy shocks or four hours of continuous analysis and treatment. Even if the battery is only partially used, the remaining standby life is substantially reduced after activation, necessitating a prompt replacement.
Factors That Reduce Battery Durability
The actual performance of an AED battery can deviate from the stated lifespan due to environmental and operational factors. Temperature is a major variable, as storing the device in areas of extreme heat or freezing cold accelerates the battery’s internal degradation. Manufacturers recommend a stable storage environment, typically between 50°F and 77°F (10°C to 25°C), to preserve the power cells.
Environments with high humidity or corrosive elements can compromise the battery’s integrity and electrical connections. Sustained exposure to adverse conditions will shorten the battery’s functional life. The device itself contributes to battery drain through routine self-tests performed to confirm readiness. These frequent, low-power system checks incrementally reduce the overall standby life.
Monitoring Status and Replacement Protocols
Users must monitor the AED’s status indicator to confirm battery readiness, as this is the clearest sign of device health. A solid green light or “OK” symbol indicates the device has sufficient power to complete a rescue. Conversely, a flashing or missing indicator, coupled with an audible prompt, signals a low-power warning and the need for immediate action.
It is important to understand the difference between a battery’s shelf life and its installed life. The “Install By” date on the packaging represents the shelf life, which is the latest date the battery should be placed into the AED for optimal performance. The installed life begins the moment the battery is secured in the device. Batteries must be replaced by their expiration date or immediately following a low battery warning. Furthermore, the battery must be replaced after any deployment that required delivering a shock, as the high-energy discharge depletes the remaining operational capacity.