Battery Expiration GuideQuick guide to everything you need to know about battery expiration dates.
Guide to Battery Expiration Dates
This guide will provide an overview of battery expiration dates including what "expired" means, differences between varying sizes and chemistries, where to find your battery's expiration information, and general questions about batteries.
What does an "expired" battery mean
The meaning of expired for batteries is different from the expired used when talking about food products. When a battery is expired, it means that the battery's manufacturer can no longer guarantee that the battery has a full life or charge. More specifically battery expiration dates are based upon when the batteries total self discharge will exceed 20%.
What is a self discharge rate?
A batteries self discharge rate is the speed at which a battery loses charge while sitting idle. Many people assume that batteries remain fully charged until they are used, but in reality batteries begin losing charge directly after they are manufactured. The rate of discharge varies between battery type and brand and can even be affected by the temperature at which the batteries are stored. For a more in depth look at the differences in self discharge rates visit our guide to battery chemistry or read table 2A below.
Where do I find my battery's expiration date?
The location of the expiration date varies depending on the type of battery and the packaging that is used. In the case of button cell batteries many of them will have it on their box or plastic packaging, but will almost never actually be on the battery itself. Most batteries will have the date printed on each individual battery near the chemical composition or battery type information. Most times it will be easily visible and often is highlighted and separated from other text by a colored boxed area or some other distinguishing feature.
What is the shelf life of my batteries?The shelf life of batteries will depend on the type and manufacturer but here is a table of generally correct shelf lives. For more accurate information on your batteries I would suggest following one of the below links to different manufacturers websites.
- Energizer Shelf Lives
- Duracell Batteries
- Efest Warning Information Page
- Panasonic Shelf Lives (shelf life information is on pages 46-50)
What storage factors affect the performance/expiration date of my battery?Temperature:
Batteries should be stored at a cool temperature as any high heat environment will accelerate the self discharge process. However, storing a battery in a temperature that is too cold can also adversely affect the chemical components within the battery. Optimal temperature ranges for batteries vary depending on chemistry and brand but most batteries are suggested for 15°C storage. For a comprehensive look at battery temperatures visit the guide to battery chemistry or read through th table 1A below.
|Nickel-Metal Hydride (NiMH)||Nickel-Zinc (NiZn)||Rechargeable Alkaline||Alkaline||Lithium||Carbon Zinc, Zinc Chloride|
|Temperature range for use||-4 to 149°F (-20 to 65°C)||-4 to 140°F (-20 to 60°C)||-4 to 140°F (-20 to 60°C)||0 to 131°F (-18 to 55°C)||-40 to 140°F (-40 to 60°C)||0 to 130°F (-18 to 55°C)|
|Battery Type (recoverable capacity when battery is stored at temperature for 1 year)||
Lead Acid (fully charged)
Nickel-based(at any charge)
Lithium Ion (full charge)
|60°C||38% (after 6 months)||70%||60%|
It is not good to store batteries out of package, whether carried loosely in a purse, or jumbled in a junk drawer. Keeping opened batteries with other metal objects like coins, keys, paper clips, nails, can lead to potential short circuiting of the batteries which will raise temperatures and put the batteries at a greater risk of leakage. Also keeping a "battery bin" for mixing and matching leftover batteries is a bad idea as using batteries of different capacities in the same device can lead to leakage through overworking of the weaker battery.
Battery Self Discharge Rates 2A:
|Battery System||Estimated self-discharge|
|Primary Lithium-Metal||10% in 5 years|
|Alkaline||7-10 year shelf life, self discharge at about 2-3% per year|
|Lead-Acid||5% per month|
|Nickel-based||10-15% over the first 24 hours and then 10-15% every month afterwards|
|Lithium-ion||5% over the first 24 hours, then 1-2% per month afterwards|