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What is an SR626SW Battery?
SR626SW Battery Specifications
SR626SW Battery Features
SR626SW Battery Advantages
SR626SW Battery Applications
SR626SW Battery Equivalent
SR626SW vs Other Button Cell Batteries
How to Replace an SR626SW Battery?
Where to Buy SR626SW Batteries?
Safe Handling and Storage of SR626SW Batteries
Frequently Asked Questions

SR626SW Battery Everything You Need to Know

06 June 2025 1081

Tiny but mighty! Button cell batteries power countless small devices we use every day. One of the most common and reliable types is the SR626SW. You might have seen it in watches, calculators, medical devices, or small gadgets.

This guide will tell you everything you need to know about the SR626SW battery. We'll cover its size, what it's made of, where it's used, how it compares to others, and how to use it safely.

What is an SR626SW Battery?

The battery SR626SW is a small, round silver oxide button cell battery. It is commonly used in compact electronic devices like wristwatches, medical tools, calculators, and small toys. It is highly regarded for its stable voltage output, long shelf life, and reliable performance in precision equipment.

The "SR"

The "SR" in its name is the key. It stands for Silver Oxide chemistry. This means it uses a chemical reaction involving silver oxide to create electricity.

The "W"

You might see "SW" at the end. This doesn't change the core battery size or chemistry. The "W" often indicates that the battery meets certain international standards or specifications, ensuring it works reliably in the devices designed for it.

Dimensions

Shape: Round (like a coin or button).

Diameter: 6.8 millimeters (mm). This is how wide the battery is across its face.

Height: 2.6 millimeters (mm). This is how thick the battery is from top to bottom.

SR626SW Battery Specifications

Parameter	Specification	Description
Size/Model Designation	SR626SW (Common Equivalent: 377, SR66, AG4, SG6)	Industry standard nomenclature. The "SR" denotes chemistry, "62" indicates diameter group, and "6" indicates height group.
Physical Dimensions	Diameter: 6.8 mm <br> Height: 2.6 mm	Standard measurements. Critical for compatibility. Ensure replacement matches exactly.
Chemistry	Silver Oxide	Anode: Zinc (Zn), Cathode: Silver Oxide (Ag₂O), Electrolyte: Alkali (e.g., Sodium Hydroxide). Provides stable voltage & high energy density.
Nominal Voltage	1.55 Volts (V)	Measured voltage under standard load. Maintains near-constant voltage throughout most of its discharge life.
Nominal Capacity	20 - 28 milliamp-hours (mAh)	Total charge stored. Varies slightly between manufacturers. Higher mAh = longer runtime in compatible devices.
Voltage Behavior	Flat Discharge Curve	Voltage remains exceptionally stable (around 1.55V - 1.45V) until nearly fully depleted. Ideal for precision devices.
Operating Temperature	-10°C to +60°C (14°F to 140°F)	Range where performance meets specifications. Avoid storage or use outside this range.
Standard Discharge Current	0.1 mA - 0.2 mA (typical for watches)	Average current draw for common applications. Actual runtime depends on device requirements.
Max Continuous Current	~5 - 15 mA (brief pulses only - check device specs)	Not designed for high-drain devices. Excessive current draw shortens lifespan significantly.
Shelf Life	Up to 3+ years (at 20°C / 68°F)	Excellent charge retention when stored properly (cool, dry). Loses less than 10% charge per year.
IEC Designation	SR66	International Electrotechnical Commission standard size code.
ANSI/NEDA Designation	377	American National Standards Institute / National Electrical Distributors Association standard code.
Weight	Approximately 0.6 - 0.8 grams	Varies slightly by manufacturer.

SR626SW Battery Features

So, what makes the SR626SW watch battery stand out? Here are its standout characteristics:

Steady Voltage Output:The most significant feature. It provides a very stable 1.55V almost constantly until it runs out of energy. This precision is vital for devices that need reliable power.

High Energy Density: Even though it's tiny, it packs a lot of useful energy into its small package, helping it last longer.

Long Service Life: Devices using batteries SR626SW typically don't need frequent battery changes. They are efficient.

Excellent Leak Resistance: Silver oxide batteries are generally much less likely to leak harmful chemicals inside your device compared to older alkaline battery types, especially as they age. This helps protect your electronics.

Reliability in Temperature: Performs consistently across a wide range of normal indoor and outdoor temperatures.

Relatively Flat Discharge Curve: The graph showing power output versus time is fairly flat, meaning it doesn't slowly fade out; it works strongly and then stops fairly abruptly near the end of its life.

SR626SW Battery Advantages

Precision: Ideal for devices where consistent power is essential (watches, timers, medical sensors).

Longevity: Lasts longer than alkaline equivalents in high-precision devices due to its stable voltage. A device will work correctly until the battery is nearly dead, instead of slowly becoming unreliable.

Leak Resistance: Greatly reduces the risk of damaging your valuable device from battery leaks.

Shelf Life: You can stock up without worrying they will go bad quickly.

Wide Device Compatibility: Works in the huge range of devices designed for batteries of its size and voltage.

Low Self-Discharge Rate: It loses its charge very slowly when not in use, helping maintain performance even after months in storage.

Environmentally Safer (Compared to Older Technologies): Modern watch battery SR626SW is mercury-free, making them more environmentally friendly and safer to handle and dispose of.

SR626SW Battery Applications

The watch batteries SR626SW are incredibly common! You'll find them powering many small devices:

Watches: Both analog (with hands) and digital wristwatches. It's a very common watch battery.

Calculators: Especially small pocket calculators.

Small Electronic Games & Toys: Battery-powered mini-games.

Medical Devices: Hearing aids (though sizes vary, SR626SW is used in some models), thermometers, blood glucose meters.

Fitness Trackers: Smaller or older models.

Key Fobs: For car remotes or home security keys.

Digital Thermometers & Hygrometers: For measuring temperature and humidity.

Laser Pointers & Small LED Lights: Small light sources.

Computer Motherboards: Providing backup power for the BIOS chip (CMOS battery) in many computers (though CR2032 is more common here now).

Small Gadgets: Pen lights, electronic jewelry, mini-instruments.

SR626SW Battery Equivalent

Battery names can be confusing! You might see other labels on batteries that look identical to the sony SR626SW. These are usually direct equivalents, meaning they are the same battery size (6.8mm x 2.6mm) and chemistry (silver oxide, 1.55V). They are fully interchangeable.

Common equivalents include:

377: The most common ANSI/NEDA standard number used for this battery, especially in North America. It's physically and electrically identical to the SR626SW (silver oxide, 6.8x2.6mm, 1.55V).

SR66: The official IEC (International Electrotechnical Commission) international designation for the standard silver oxide battery of this size. It signifies an SR626SW equivalent meeting global specifications.

AG4: A traditional, widely recognized designation, particularly common in Europe and for watch batteries. It refers to the exact same silver oxide battery as the SR626SW.

SG6: Another historical industry designation, similar to AG4, used by some manufacturers or regions to label the standard 6.8x2.6mm silver oxide cell (SR626SW/377).

SB-BU: The specific model designation used by the Renata brand (owned by Swatch Group) for their version of the SR626SW/377 battery, guaranteeing its quality for watches and precision devices.

V377: A common variation or package label used by various manufacturers like Energizer to denote their 377 (SR626SW replacement) battery.

D377: A frequent packaging variation used by brands to identify their specific 377 (SR626SW equivalent) battery product line.

G4: An older, legacy designation that is functionally the same as the SR626SW/377 silver oxide battery, though less commonly used today.

Comparison Table

Specification	SR626SW	377	SR66	AG4	SG6	SB-BU	V377	D377	G4
Origin/Type	Base model (Manufacturer)	ANSI/ NEDA Standard	IEC Standard	Traditional Designation	Traditional Designation	Renata Brand Code	Brand Variation	Brand Variation	Legacy Designation
Chemistry	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)
Nominal Voltage	1.55V	1.55V	1.55V	1.55V	1.55V	1.55V	1.55V	1.55V	1.55V
Dimensions (D × H)	6.8mm × 2.6mm	6.8mm × 2.6mm	6.8mm × 2.6mm	6.8mm × 2.6mm	6.8mm × 2.6mm	6.8mm × 2.6mm	6.8mm × 2.6mm	6.8mm × 2.6mm	6.8mm × 2.6mm
Capacity	20-28mAh	20-28mAh	20-28mAh	20-28mAh	20-28mAh	20-28mAh	20-28mAh	20-28mAh	20-28mAh
Applications	Watches, medical, devices	Watches, calculators	Global electronics	European watches, electronics	Industrial devices	Precision watches	General electronics	General electronics	Older electronics
Key Distinction	Original nomenclature	Most common retail label	Global standardization	Common in EU packaging	Alternative to AG4	Renata specialty guarantee	Voltage-focused labeling	Durability-focused labeling	Rarely used today
Interchangeable	Base reference	✅ 100% Identical	✅ 100% Identical	✅ 100% Identical	✅ 100% Identical	✅ 100% Identical	✅ 100% Identical	✅ 100% Identical	✅ 100% Identical

SR626SW vs Other Button Cell Batteries

SR626SW vs. SR621SW

Parameter	SR626SW	SR621SW	Impact
Chemistry	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	Identical energy stability
Dimensions	6.8mm × 2.6mm	6.8mm × 1.65mm	❌ Non-interchangeable: SR621SW is 36% thinner
Capacity	20–28 mAh	~13–17 mAh	⚠️ SR621SW has 40% less runtime
Voltage	1.55V	1.55V	Identical performance
Common Equivalents	377, SR66, AG4	SR60, 364, AG1	Distinct naming systems
Typical Use	Watches, calculators	Micro devices, jewelry	❌ Never force fit – may damage contacts or casing

SR626SW vs. LR626 (Alkaline Equivalent)

Parameter	SR626SW	LR626	Impact
Chemistry	Silver Oxide (Ag₂O)	Alkaline (Zn/MnO₂)	⚠️ LR626 leaks more easily (especially when depleted)
Nominal Voltage	1.55V (stable)	1.5V (declining)	❌ LR626 drops to 1.2V mid-life → Watches run slow, devices malfunction
Discharge Curve	Flat (>90% life at 1.55V)	Gradual decline	✅ SR626SW: Device works fully until sudden failure
Shelf Life	3+ years	2–3 years	⚠️ Alkaline self-discharges faster
Cost	Higher (~$1.50/unit)	Lower (~$0.75/unit)	⚠️ Alkaline costs less upfront but fails sooner in precision devices
Leak Risk	Low	Moderate-High	❌ LR626 leaks may corrode device internals

SR626SW vs. 377

Parameter	SR626SW	377	Reality Check
Chemistry	Silver Oxide (Ag₂O)	Silver Oxide (Ag₂O)	✅ Identical
Dimensions	6.8mm × 2.6mm	6.8mm × 2.6mm	✅ Identical
Voltage & Capacity	1.55V, 20–28 mAh	1.55V, 20–28 mAh	✅ Identical performance
Naming Standard	Manufacturer code	ANSI/NEDA standard	Retail packages often say "377 (SR626SW)"
Use Cases	Watches, medical devices	Same as SR626SW	✅ 100% interchangeable

Summary Table

Comparison	Interchangeable?	When to Use	Risk of Substitution
SR626SW vs. SR621SW	❌ No	Never – size mismatch prevents fit	Device damage
SR626SW vs. LR626	⚠️ Conditionally	Only if device manual allows alkaline cells	Poor performance/leak damage
SR626SW vs. 377	✅ Yes	Anytime – identical specs	None

How to Replace an SR626SW Battery?

1

Identify
Locate the battery compartment on your device. It might be on the back, underneath, or require opening a case (like on a watch).
2

Tools
You may need a small screwdriver to open a panel. For watches, a small case knife or specialized watch opener tool is often required. Plastic tweezers or gloves are recommended for handling the battery to avoid fingerprints or shorts. Never use metal tweezers that can touch both battery terminals!
3

Open Carefully
Follow the instructions for your device. Watch backs often snap off or screw off. Use gentle pressure to avoid damaging the device.
4

Note Orientation
Before removing the old battery, look carefully at how the "+" (positive) and "-" (negative) sides are positioned. The "+" side might face up or down depending on the device. Draw a picture or take a photo if it helps.
5

Remove Old Battery
Gently pry it out. Plastic tweezers are useful.
6

Clean (Optional)
Lightly clean the battery contacts in the device with a cotton swab dipped in rubbing alcohol if they look dirty or corroded. Let dry completely.
7

Insert New Battery
Place the new button battery SR626SW (or 377/equivalent) into the compartment exactly as the old one was oriented (+ and - sides matching).
8

Close Securely
Replace the cover or back plate securely, ensuring any sealing gasket is in place if the device is water-resistant.
9

Test
Power on your device to check if it works.
10

Dispose
Recycle your old battery properly! Do not throw it in the trash. Take it to a battery recycling point (many stores have bins).

Where to Buy SR626SW Batteries?

1.Retail Stores:

Pharmacies & Drugstores

Big Box Stores (like Walmart, Target)

Electronics Stores (like Best Buy)

Supermarkets

Hardware Stores (often near checkout counters)

Jewelry Stores & Watch Repair Shops

2.Online Retailers:

Amazon

eBay

Batteries Plus Bulbs

Direct from Battery Manufacturer Websites (Energizer, Duracell, Panasonic, Sony/Murata, Maxell)

Many specialized electronics component websites.

Tips for Buying:

Check Expiry/Manufacture Date: Buy the freshest batteries possible, especially if buying in bulk. Look for dates stamped on the packaging.

Brand: Reputable brands (Energizer, Duracell, Panasonic, Sony/Murata, Maxell, Renata for watches) generally offer better quality and leak resistance.

Packaging: Ensure the packaging isn't damaged or compromised.

Quantity: You often get a better price per battery by buying multi-packs, but only buy what you'll use within a few years.

Safe Handling and Storage of SR626SW Batteries

Swallowing Hazard (SUPER IMPORTANT):

KEEP AWAY FROM CHILDREN AND PETS! SR626SW watch batteries are the perfect size to be swallowed. This is a medical emergency!

If swallowed, they can get stuck in the throat or esophagus and cause severe burns or death within hours.

If you suspect someone has swallowed a button battery, call emergency services immediately (911 in the US/Canada, 999 in UK, 112 in EU).

Store batteries securely out of reach. Consider products with child-resistant battery compartments.

Tape dead batteries before disposal to reduce hazards.

Electrical Hazards:

Do not carry loose batteries in pockets or bags where they can contact keys, coins, or other metal objects. This could cause a short circuit, overheating, leakage, or even fire.

Keep batteries in their original packaging until needed.

Install Carefully:

Always check the orientation (+/-) matches the device diagram. Putting it in backwards can damage the device.

Never force a battery into a compartment.

Storage:

Store in a cool, dry place at room temperature (ideally 15-25°C or 59-77°F).

Avoid high humidity.

Do not store near a heat source or in direct sunlight.

Consider using the original packaging or dedicated battery storage boxes.

Disposal:

DO NOT throw in regular household trash.

Button batteries contain metals that are bad for the environment.

Take used batteries to a certified battery recycling location. Many electronics stores, hardware stores, and community centers have drop-off bins. Your town might also have hazardous waste collection days.

Leakage:

While less common with silver oxide, avoid mixing old and new batteries, damaging them, or storing them in extreme conditions to minimize risk.

If a battery leaks in your device, clean the contacts carefully with a cotton swab and rubbing alcohol (isopropyl alcohol), wearing gloves.

The SR626SW (also known as 377) is a dependable workhorse in the world of tiny power sources. Its silver oxide chemistry provides the steady voltage essential for accurate timekeeping, precise medical readings, and reliable gadget performance.

By understanding its specifications, uses, and how to handle it safely, you can ensure your small devices keep running smoothly for a long time. Always recycle your used batteries responsibly!

Frequently Asked Questions

Are 377 and sr626sw the same?

Yes, 377 and coin battery SR626SW refer to the same type of button cell battery, though they are identified by different naming conventions. They are both button cell batteries with identical dimensions and voltage.

Can i use sr626sw instead of sr621sw?

Generally, it is not recommended to use sony battery SR626SW instead of SR621SW. They are different battery models with distinct specifications. SR626SW is slightly taller than the SR621SW, but they have the same diameter.

How to replace sr626sw watch battery?

1.Prepare Tools: a small screwdriver, plastic tweezers, and a new button cell SR626SW. 2.Open the Watch Back. 3.Remove the Old Battery. 4.Install the New Battery. 5.Reassemble the Watch. 6.Test the Watch.

What battery is compatible with sr626sw?

Several battery models are compatible with sony SR626SW watch battery due to their identical or very similar specifications: 377, 376, AG4, SR66, SR626, V377, D377, GS4, SB-AW.

What is SR626SW also known as?

SR626SW button cell battery is also known as 377, AG4, SR66, V377, D377, GS4, SB-AW, 177, or 377A. These are all equivalent battery models with the same dimensions (6.8mm diameter × 2.6mm height) and similar specifications, though they may be produced by different manufacturers or regions.

What does SW mean on a watch battery?

On a watch battery, the suffix "SW" stands for "Silver-Oxide Watch" or "Special Watch", indicating that the battery is specifically designed for use in watches, particularly those requiring low self-discharge rates and stable voltage output over time.

What is the size of SR626SW battery?

The SR626SW button cell is a silver-oxide battery with a voltage of 1.55V, primarily found in watches and small electronic devices. Its dimensions are 6.8 mm in diameter and 2.6 mm in height.

Is AG4 battery the same as SR626SW?

AG4 is not the same as button cell battery SR626SW, though they share the same dimensions (6.8 mm diameter × 2.6 mm height). SR626SW offers a more stable voltage and higher capacity (typically 25–30 mAh) compared to AG4 (around 17–22 mAh).

How long do SR626SW batteries last?

The lifespan of an button cell SR626SW battery typically ranges from 1 to 3 years, depending on factors such as the device's power consumption, battery quality, and usage conditions.

Where to buy sr626sw?

SR626SW sony battery can be purchased from various reliable sources: online marketplaces, electronics stores, specialized battery retailers.

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Liam Carter

Liam Carter is an accomplished Senior Electronic Engineer with over a decade of expertise in the design, development, and optimization of core electronic components. His career has focused on pioneering advancements in semiconductor devices, including precision resistor networks, high-frequency transistor architectures, and innovative IC packaging solutions. With extensive experience in circuit simulation, failure analysis, and thermal management strategies, he has successfully led cross-functional teams in delivering robust electronic systems for industrial automation and IoT applications. His technical leadership in material selection, signal integrity validation, and miniaturization techniques has consistently elevated product performance while reducing manufacturing costs, solidifying his reputation as a forward-thinking innovator in electronic component engineering.