AG4, LR626, LR66, 177/376/377, SR626, SR626SW Battery Equivalents

AG4, LR626, LR66, 177/376/377, SR626, and SR626SW batteries are very popular non-rechargeable button/coin cell batteries, available in several chemistries and manufactured by practically all battery brands.

These batteries are commonly found in wrist watches, calculators, and similar small electronic devices requiring a reliable power source.

Updated: April 9, 2024.

SR626SW, LR626, 377, AG4 Battery Features and Specifications

SR626SW/LR626 batteries feature a physical dimensions of (DxH) of 2.6 x 6.8 mm (~0.1023 x 0.2677 inches).

According to the IEC standard, and depending on their chemistry, these batteries should be labeled LR626 (alkaline) or SR626 (silver-oxide) batteries, and according to the ANSI standard, 1176SO batteries.

Sometimes shorter, two-digit code is used: LR66 for alkaline and SR66 for silver-oxide batteries.

Many manufacturers use their own labels for these batteries, but they also tend to add IEC and other standard codes, including short descriptions about the chemistry, nominal voltage, battery equivalents, and similar.

LR626 (alkaline) or SR626 (silver-oxide) capacities depend on the chemistry but also on the cut-off voltage of the used device - alkaline batteries' voltage quickly drops, making them not so suitable for electronic devices like wrist watches and similar.

Since these batteries are rather small, so is their price per individual battery. In short, if you need an LR626/SR626 wrist watch battery, go for an SR626 or SR626SW battery.

Few notes:

• AG4 vs SG4: AG4 should be 'alkaline G4' and SG4 should be 'silver-oxide G4' battery. However, sometimes manufacturers mark silver-oxide batteries with both SG4 (correct) and AG4 (not correct) to emphasize that their battery is a replacement for AG4/SG4/LR66/SR66/LR626/SR626/SR626SW battery.
• if the battery code starts with the 'L', then it should be an alkaline R626 battery (LR626, LR66, AG4),
• if the battery code starts with the 'S', then it is a 'silver-oxide' R626 coin cell (SR626, SR66, SR626SW).
• if the battery code after the digits contains 'P', then it is the battery with a potassium hydroxide electrolyte.
• if the battery code after the digits contains 'S', then it is the battery with a sodium hydroxide electrolyte.
• if the battery code after the digits doesn't contain 'P' or 'S', then probably that battery contains an organic electrolyte - we emphasize 'probably' because some manufacturers simply drop out these letters when labeling their batteries.
• if the battery code after the digits contains 'W', then the battery complies with the IEC 60086-3 watch batteries standard - most manufacturers of '626' batteries label their silver-oxide batteries as SR626SW to emphasize that these batteries are silver-oxide batteries for wrist watches - and if they are good for wrist watches, then they are good for other electronic devices, too.
• some manufacturers use number labels, like 376 and 377. Generally speaking, the 376 battery is a non-rechargeable silver-oxide high-drain battery, while the 377 battery is a non-rechargeable silver-oxide low-drain battery.

Modern 376 and 377 are suitable as wrist watch batteries since they feature stable output voltage. However, 376 batteries feature better high-drain current tolerance, while 377 batteries feature a lower self-discharge rate.

To prevent confusion and thanks to modern chemistry and battery technology, some manufacturers offer multi-drain 376/377 batteries (compatible with SR626SW batteries, of course) that feature good tolerance to high-drain pulse currents and low self-discharge rate.

 LR626 vs. SR626 Batteries Comparison Chart

Comparison and examples of alkaline and silver-oxide 6.8 x 2.6 mm coin-cell batteries are given in the following SR626SW watch battery replacement chart:

As one can see, LR626/SR626 batteries are available in two different chemistries: alkaline and silver-oxide.

LR626/AG4 Battery Voltage

Alkaline LR66/LR626 batteries have a nominal voltage of 1.5 volts, and it relatively quickly drops over time down to 0.8-1.0 volts.

Since sensitive electronics might have issues operating at such low voltage and may have issues with reliability when using alkaline AG4/LR66/LR626 batteries.

Also, their capacity when drained down to 1.0 volts is lower when compared with silver-oxide batteries by some 30% and up to 50% lower when drained down to 1.2 volts.

SR626/SR626SW/376/377 Battery Voltage

Silver-oxide SR626/SR626SW batteries have a nominal voltage of 1.55 volts, and it is rather constant over time as the battery is drained. Also, these batteries have a larger capacity providing a much longer operating time for various devices using a single battery replacement.

Note that some silver oxide SR626 batteries are designed as high-drain batteries and are more suitable for digital watches and similar electronic devices, while other SR626 batteries are designed as low-drain batteries and are more suitable for analog watches, digital watches without alarms and LEDs, thermometers, and similar.

But, most manufacturers today offer so-called multi-drain 376/377 (SR626SW) batteries, suitable for both digital and analog watches, toys, thermometers, keychain LED flashlights, and similar devices.

SR626SW, 377, 376 Batteries Comparison Chart

The following cross-reference chart lists some of the most popular  SR626, 377, and 376 battery models, with their most important features and specifications:

As one can see, actual performances vary depending on the discharge current and temperature and the battery age.

Of course, these are just some of the most popular silver-oxide 6.8 x 2.6 mm button/coin cells on the market.

SR626SW vs. SR621SW Batteries

Both SR626SW and SR621SW batteries are silver-oxide non-rechargeable batteries suitable for powering wrist watches and other sensitive electronic devices.

The main difference between these two batteries is their size and hence discharge characteristics:

• SR626SW battery: (D x H) 6.8 x 2.6 mm, 1.55V, 25-27 mAh
• SR621SW battery: (D x H) 6.8 x 2.1 mm, 1.55V, 18-23 mAh.

The height difference of the SR626SW and SR621SW batteries is just 0.5 mm, which isn't much - however, while battery compartments intended for SR626SW batteries may accept smaller SR621SW batteries, contacts with the SR621SW battery may NOT be fully reliable.

On the other hand, the battery compartment intended for the SR621SW battery may not accept at all SR626SW battery, or it may deform.

In short, if You do need an SR626SW battery, go for a silver-oxide 6.8 x 2.6 mm battery from reputable brands.

LR626/SR626 Batteries Safety Issues

Modern LR626/SR626 batteries don't contain mercury, cadmium, and other heavy metals or dangerous toxins.

However, these batteries are 'small shiny objects' that may attract kids and pets, and due to their dimensions, these batteries are easily swallowed.

If they get swallowed, these batteries may start electrolytic reactions that may cause chemical burns, which are very dangerous.

Although these batteries don't have a 'large' capacity and are just ~1.5V, if they get swallowed, be sure to immediately contact the nearest emergency center and act according to their instructions.

How to Properly Dispose of LR626 and SR626SW Batteries?

Disposing of small batteries like LR626 (alkaline) and SR626SW (silver oxide) requires careful consideration due to their chemical components and potential environmental impact. Here's a guide on how to properly dispose of these batteries:

LR626 (Alkaline Batteries)

• Check Local Regulations: First, it's essential to check the local regulations regarding alkaline battery disposal. Many areas allow these batteries to be disposed of with regular trash since they're considered non-hazardous waste. However, local guidelines may vary.
• Recycling Centers: Look for local recycling centers that accept alkaline batteries. While not all recycling programs accept them, many do as part of a special collection or hazardous waste disposal day.
• Battery Recycling Programs: Some retailers and public facilities participate in battery recycling programs where you can drop off used batteries. These programs ensure that the batteries are recycled responsibly.

SR626SW (Silver Oxide Batteries)

• Hazardous Waste: Because they contain silver oxide, SR626SW batteries are classified as hazardous waste and should not be disposed of with regular household waste.
• Special Collection Sites: Look for hazardous waste collection sites in your area. Many municipalities offer special disposal services for batteries and other hazardous materials, ensuring that harmful substances are not released into the environment.
• Retail Drop-Off: Some watch shops, electronics stores, and pharmacies offer drop-off points for used watch batteries, including silver oxide batteries. These retailers often have partnerships with recycling companies that handle hazardous materials properly.

General Tips for Both Types of Batteries

• Tape the Terminals: Before disposing of or recycling the batteries, it's a good practice to tape the terminals to prevent short-circuiting, especially if they're being collected with other batteries.
• Store Safely Until Disposal: If you're accumulating batteries for a recycling run, store them in a cool, dry place away from heat sources and ensure they're kept out of reach of children and pets.
• Never Burn or Puncture: Batteries should never be burned or punctured as this can release toxic substances and may cause injury.
• Check for Mail-In Programs: Some manufacturers and recycling programs offer mail-in options where you can send used batteries for proper disposal.

Proper disposal of LR626 and SR626SW batteries not only complies with environmental regulations but also contributes to the responsible recycling of materials and the reduction of hazardous waste in landfills. Always opt for recycling when available and follow local guidelines for disposal.

LR626/SR626SW Batteries Frequently Asked Questions - LR626/SR626SW FAQ

Here are some of the most commonly asked questions about alkaline and silver-oxide 6.8 x 2.6 mm batteries:

What battery is equivalent to SR626SW?

SR626SW battery is a 6.8 x 2.6 mm silver-oxide battery with sodium hydroxide electrolyte, which complies with the IEC 60086-3 watch batteries standard.

Since most multi-drain 376/377 and SR626 batteries are designed as wrist watch batteries, it shouldn't be too hard to find a 6.8 x 2.6 mm battery that also comes with a label of "SR626SW" battery.

Is 377 battery the same as SR626SW?

377 battery and SR626SW battery share the same physical dimensions of 6.8 x 2.6 mm, and probably the same battery chemistry.

However, although these batteries are compatible with most applications, they are not necessarily "exactly the same" batteries.

What replaces a 626 watch battery?

The proper label of the "626" battery should be either LR626 or SR626(SW) battery - a "626" 6.8 x 2.6 mm watch battery may be replaced with a 6.8 x 2.6 mm SR626W, SR626SW, 376, 377, and 376/377 battery.

What is an SR626SW battery?

SR626SW battery is a non-rechargeable silver-oxide button/coin 6.8 x 2.6 mm cell with sodium hydroxide electrolyte and it complies with the IEC 60086-3 watch batteries standard.

What Duracell battery replaces SR626SW?

Duracell manufacturers D377/376 6.8 x 2.6 mm battery which is equivalent to most SR626SW batteries.

Is Energizer 377 the same as SR626SW?

Yes, Energizer 377/376 battery is a 6.8 x 2.6 mm battery based on the silver-oxide chemistry which is equivalent to most SR626SW batteries.

Are 626 and 377 batteries equivalent?

If the 626 battery is a silver-oxide battery, then yes, 626 and 377 batteries are more or less compatible batteries. We say "more or less" since these batteries may differ in a few other important details as well.

Are 357 and 377 batteries the same?

357 batteries are 11.6 x 5.4 mm batteries, while 377 batteries are 6.8 x 2.6 mm batteries - they differ in size, capacity, and other important features, making them anything but compatible.

Are 377 and 392 batteries interchangeable?

377 batteries feature physical dimensions of 6.8 x 2.6 mm, while 392 batteries feature physical dimensions of 7.9 x 3.6 mm, so no, they are not interchangeable.

Can I use a 364 battery instead of a 377?

364 battery features physical dimensions of 6.8 x 2.1 mm (just as SR621SW battery), and it is generally not compatible with 377 battery with physical dimensions of 6.8 x 2.6 mm.

Some watches and other similar devices that accept 377 batteries may also function properly with 364 batteries (and vice versa), but issues with contacts are also possible.

What battery is smaller than a 377?

SR416SW battery (4.8 x 1.6 mm), SR512SW (5.8 x 1.3 mm), SR516SW (5.8 x 1.6 mm), SR521SW (5.8 x 2.1 mm), SR527SW (5.8 x 2.7 mm), SR616SW (6.8 x 1.65 mm) and SR621SW (6.8 x 2.1 mm) batteries are smaller than 377 battery.

What does SW mean on a battery?

If the battery code after the digits contains 'S', then it is the battery with sodium hydroxide electrolyte, and if the battery code after the digits contains 'W', then the battery complies with the IEC 60086-3 watch batteries standard.

Also, most manufacturers of '626' batteries label their silver-oxide batteries as SR626SW to emphasize that these batteries are silver-oxide batteries for wrist watches - and if they are good for wrist watches, then they are good for other electronic devices, too.

How do you know which battery to buy for a watch?

Check the documentation of your watch, or check the official website of the watch manufacturer, use the search option (if available) and look for the watch documentation or ask for their support.

Also, check on the Google "watch name/label" + "battery".

How to replace the SR626SW watch battery?

The easiest but not the cheapest way of replacing SR626SW or any similar watch battery is to let the watchmaker do the job - the watch is carefully opened using special tools, the battery is located and replaced with the new one, and the watch is properly closed.

However, while replacing the battery, the watchmaker may check other watch parts, and if the wear is noticed, they can also be replaced.

Obviously, the battery can be replaced at home. However, ask yourself if You can spot and replace worn parts of your watch.

Where to buy watch battery SR626SW?

The SR626SW watch battery can be purchased in most hardware or even office stores, or the battery can be ordered from online shops.

What "CR" battery is equivalent to an SR626SW battery?

No "CR" battery is equivalent to an SR626SW battery - "CR" batteries are non-rechargeable 3.0V lithium manganese dioxide batteries, while SR626SW batteries are non-rechargeable 1.55V silver-oxide batteries.

How to properly store LR626 and SR626SW batteries to prolong their lifespan?

Proper storage of LR626 (alkaline) and SR626SW (silver oxide) batteries can significantly prolong their lifespan and ensure they retain their charge until you're ready to use them.

Best practices for storing alkaline and silver-oxide batteries include:

• Cool and Dry Conditions: Store your batteries in a cool, dry place. High temperatures can accelerate the self-discharge rate of batteries and lead to leakage or swelling, especially in alkaline batteries. Ideal storage temperatures are between 50°F (10°C) and 77°F (25°C).
• Avoid Humidity: Moisture can corrode battery contacts and potentially cause a short circuit. Ensure your storage area is dry.
• Keep Away from Metal Objects: Store batteries away from coins, keys, and other metal objects that could potentially short-circuit them.
• Original Packaging: If possible, keep batteries in their original packaging to avoid exposure to environmental factors and to prevent them from touching each other or metal surfaces.
• Battery Case or Holder: For loose batteries, use a plastic battery case or holder to keep them separated and protected. Make sure the case is specifically designed for button/coin cells to prevent movement and contact.
• Avoid Refrigeration: While a cool environment is beneficial, avoid storing batteries in a refrigerator. The condensation from the refrigerator can introduce moisture, leading to corrosion. If you must store batteries in a refrigerator due to extreme ambient temperatures, place them in a tightly sealed plastic bag to keep moisture out and bring them to room temperature before use.
• Isolation for Used Batteries: If batteries are partially used but you plan to use them later, store them separately from new batteries and ensure their terminals are taped to prevent accidental discharge.

For short: if you need a 6.8 x 2.6 mm button/coin cell battery replacement for your analog or digital watch, thermometer, calculator, pager, toy, micro-LED flashlight, or similar electronic device, go for a high-quality SR626SW (376/377) battery from reputable brands which has many positive reviews.

If You are unsure regarding low-drain or high-drain models, go for a multi-drain SR626SW battery, also labeled as 367/377 battery.