| There are three types of battery life to consider -- how long it lasts just sitting there (shelf life), how long it lasts powering a particular device (use life), and how many times it can be recharged (recharge life).
Shelf life varies depending on battery type and temperature; however, there should be a date code ('03-01' or '07-02') printed on the battery’s package. This code indicates the use before date. Older batteries may have a date code in the format '1A8', which indicates the manufacturing date (in this case, 1=January and 8=1998).
- Batteries should be stored at 40-50 degrees F. Batteries should not be stored in the freezer or in very hot environments (such as a car's glove box).
- Batteries stored at a temperature above 125 degrees F will deteriorate particularly quickly.
- Zinc-Air batteries are the only type of batteries that we sell that do not begin discharging until you begin to use them. A zinc-air battery has a tab (usually plastic) that must be taken off before you use it. It begins to discharge when the tab is removed.
Use life (or how long a battery will last in a given device) depends on the current drain of the device and the capacity (mAh) rating of the battery. The basic formula is given below:
| Capacity (divided by) Current Drain (multiplied by) 0.7 (equals) Approximate Battery Life |
The factor of 0.7 makes allowances for external factors which can affect battery life. The primary factor is temperature.
- Batteries have different operating temperatures; see the Battery Comparison Chart for specific information.
- Using a battery under extreme heat may cause it to produce more energy; however, its overall life is reduced.
- Using a battery under cold conditions may cause it to produce less energy, and again, overall life is reduced.
Recharge life is the number of times a rechargeable battery can be discharged and recharged (1 cycle) and still be effective. Over time, rechargeable batteries will lose their capacity for recharging. |
