SR57, LR57, 395, 399, SR927W, SR927SW, SR927PW, SR927, SR926, LR927, LR926, SG7, AG7 Battery Equivalents and Replacements
SR57, LR57, 395, 399, SR927SW, AG7 etc. batteries are very popular button/coin cell non-rechargeable batteries, available in alkaline and silver-oxide chemistries and manufactured by practically all battery brands.
These batteries are commonly found in small electronic and electric devices requiring reliable power source like keychain flashlights, wrist watches, small remote controls and similar.
Common names/labels of these batteries include: SR57, LR57, 395, 399, SR927W, SR927SW, SR927PW, SR927, SR926, LR927, LR926, SG7, and AG7, although the most common ones are 395, 399, SR927SW and AG7 - note that labels also depend on the chemistry and the manufacturer.
SR57, LR57, 395, 399, SR927SW, AG7 batteries are button cell batteries 9.5 mm in diameter and 2.6 mm in height (0.374 x 0.102 inches) and they are manufactured as either alkaline or silver-oxide batteries.
When looking for a replacement battery, note that some manufacturers interchangeably use the same labels for both alkaline and silver-oxide batteries.
For example, AG7 battery should be 'Alkaline G7' (AG7) battery, and SG7 battery should be 'Silver G7' (SG7) battery. However, AG7 and SG7 are both often used for silver-oxide batteries, while AG7 is mostly used only for alkaline batteries - for short, manufacturers often label their silver-oxide batteries as 'SG7' and 'AG7 equivalents', despite slight voltage difference between these two chemistries.
- some manufacturers label their 'low-drain' SR57/LR57 batteries as '395 batteries' and their 'high-drain' SR57/LR57 batteries as '399 batteries'. On the other hand, some manufacturers label their SR57/LR57 batteries as '395/399 batteries' to emphasize that their batteries are of 'multi-drain' (MD) design. Most silver-oxide SR57/SR927/SR927SW batteries are of multi-drain design, but there are some manufacturers that produce both 'low-drain' and 'high-drain' silver-oxide SR57/SR927/SR927SW batteries (again: 'low-drain' are labeled as 395 and 'high-drain' batteries are labeled as 399 batteries).
- letters in the label behind the number usually describe the intended purpose or describe the electrolyte used in the battery (usually sodium hydroxide or potassium hydroxide). These days manufacturers add enough labels on the packages in order to identify their batteries that there is really no need to check the electrolyte types :)
Comparison of these chemistries is given in the following table:
|Notes||Voltage drops over time||Very constant voltage|
|Typical Labels||LR57, LR927, AG7, 395, 399||SR57, SR927SW, SR927W, SG7, 395, 399|
|Typical Capacity||40-47 mAh||50-65 mAh|
|Amazon Link||395 Alkaline Battery||395 Silver Oxide Battery|
Note: Amazon links open in the new window. Feel free to check them for the latest offers and prices.
Alkaline LR57/395/AG7 batteries: Alkaline button/coin cell batteries are reliable and cheap batteries with the nominal voltage of 1.5 volts. However, as the battery is used, output quickly voltage drops over time.
Actual capacity depends on the cut-off voltage of the used device. If it is some sort of electronic equipment requiring constant and relatively high voltage, then nominal capacity of these batteries is rather low - such device will require new replacement batteries rather quickly. If alkaline batteries are used in devices that tolerate low battery voltage, than nominal capacity is higher, since such device will operate properly even with the lower voltage.
Typical labels of alkaline batteries are LR##, LR####, AG## or similar. Typical capacity of, for example, alkaline LR57 is in the 40-47 mAh range, which is lower when compared with equivalent silver-oxide (50-65 mAh).
Shelf life depends on the manufacturer, but generally newer alkaline LR57/SR57/395/AG7 batteries have storage life of at least 3-5 years.
Cut-off voltage of alkaline batteries is around 1.0 volts.
Silver Oxide SR57/395/SG7 batteries: Silver-oxide button/coin cell batteries are the most popular type of these batteries - they cost slightly more than alkaline batteries, but they are not expensive, especially when bought in larger packages.
Also, they often have storage life of 10 or more years (this depends on the manufacturer), they have very constant output voltage during operation, which is very similar to the nominal voltage of alkaline batteries (1.55 V vs 1.50 V). This 0.05 V difference between silver-oxide and alkaline batteries is rarely of an issue even when powering sensitive electronic devices, like for example, wrist watches.
In fact, in real life more devices will have issues due to the voltage drop in alkaline batteries than with slightly larger voltage of silver-oxide batteries.
Typical labels of silver-oxide batteries are SR##, SR####, SG##, or similar. Again, some manufacturers also label them using alkaline AG## label to emphasize that their silver-oxide (SG##) batteries are replacement for alkaline AG## batteries.
Typical capacity of, for example, silver-oxide SR57 is in the 50-65 mAh range, which is larger than equivalent alkaline LR57 capacity (40-47 mAh).
Cut-off voltage of silver-oxide batteries is around 1.2 volts.
Long Story Short: if you are looking for a SR57, LR57, 395, 399, SR927W, SR927SW, SR927PW, SR927, SR926, LR927, LR926, SG7, AG7 battery replacement for a wrist watch or some similar electronic device, go for silver-oxide SR57/SR927SW/395/399 battery from reputable brand.
If you are looking for a similar battery replacement for an electric device or even a small toy, an alkaline LR57/LR927/AG7 battery from reputable brand will do the job.
Call us biased, but we generally favor silver-oxide over alkaline batteries in units that support the use of both chemistries.