SR621SW Silver Oxide Button Cell Batteries

Silver oxide button cells, like the SR621SW, are well-known for their dependable performance and compact design. They deliver a steady voltage and have an impressive shelf life, making them a go-to power source for small electronics such as watches, calculators, and medical devices. If you’re planning to replace or use this battery in different gadgets, it’s important to understand its equivalents and where it’s typically used. The SR621SW stands out from other miniature batteries in several ways, and this article takes a closer look at its wide-ranging applications and notable advantages.

What Is the SR621SW Battery?

The SR621SW is a small silver oxide button cell battery frequently found in compact electronic devices. It’s commonly used in precision tools like watches and calculators, as well as medical equipment such as glucose meters and hearing aids, thanks to its 1.55V nominal voltage. Measuring just 6.8 mm in diameter and 2.1 mm in height, it’s designed to fit perfectly into tight spaces inside small gadgets.

Silver oxide batteries like the SR621SW are valued for their long storage life and consistent voltage output. Unlike alkaline batteries, which slowly lose voltage as they drain, silver oxide cells maintain a stable output right up until they run out—an essential feature for devices that demand accuracy, like watches and medical instruments. On top of that, the SR621SW is versatile, dependable, and works reliably across a broad range of temperatures.

SR621SW Battery Equivalents

Several batteries can replace the SR621SW and be used directly in small electronic devices, thanks to their similar performance. While there may be slight differences in size, voltage, or capacity, these equivalents follow the same standards and codes. Below is a detailed list of common SR621SW replacements:

364 Battery

The 364 is a direct equivalent to the SR621SW, with identical dimensions (6.8 mm diameter × 2.1 mm height), voltage (1.55 V), and silver oxide chemistry. It delivers the same stable, long-lasting performance, making it a trusted choice for watches, calculators, and other compact electronics.

AG1 Battery

The AG1—also known as LR621—is usually an alkaline battery with the same physical size as the SR621SW but a slightly lower voltage of 1.5 V and a shorter service life. While not as long-lasting as silver oxide cells, it works well for low-drain devices or situations where frequent replacement is not an issue.

SG1 Battery

The SG1 matches the SR621SW in size (6.8 mm × 2.1 mm) and voltage (1.55 V). Designed for stable, reliable power output, it is commonly used in watches and medical instruments where precision and dependability are essential.

LR60 Battery

The LR60—sometimes labeled as 164—is another alkaline option with the same dimensions as the AG1. Like most alkaline cells, it has a lower capacity and shorter lifespan compared to silver oxide batteries, but it can be used in devices that do not require high consistency in performance.

V364 Battery

Varta’s V364 is a silver oxide replacement that fully matches the SR621SW’s voltage (1.55 V) and size. It offers dependable, long-term performance for any device designed to use the SR621SW.

D364 Battery

Produced by Duracell, the D364 has the same specifications as the SR621SW, making it a suitable option for watches, medical devices, and other small electronics. It is valued for its reliability and extended shelf life.

R621 Battery

Although the R621 may have slight differences in capacity and voltage, its performance is comparable to the SR621SW. It is suitable for similar applications, delivering consistent power output in compatible devices.

SR621SW Battery Features

Stable Voltage Output

With a nominal output of 1.55 V, the SR621SW delivers a steady and reliable voltage throughout its lifespan. This is crucial for precision devices like watches and medical instruments, where accurate, consistent power is essential. The stable voltage not only ensures proper device operation but also helps the battery reach its full service life.

Long Shelf Life

Thanks to its silver oxide chemistry and low self-discharge rate, the SR621SW can retain its charge for extended periods when stored. This makes it ideal for backup power in devices that may sit unused for long stretches, maintaining readiness whenever needed.

High Energy Density

Despite its small size, the SR621SW stores a significant amount of energy, allowing compact devices to run longer between replacements. This high energy density is especially valuable for electronics that demand long-lasting power in a minimal form factor.

Compact Size

Measuring just 6.8 mm in diameter and 2.1 mm in height, the SR621SW fits perfectly in space-constrained devices. Its miniature form makes it a popular choice for wristwatches, calculators, hearing aids, and various medical instruments.

Wide Operating Temperature Range

The SR621SW is designed to function reliably in environments from –10 °C to +60 °C. Whether in cold storage or hot outdoor conditions, it maintains consistent performance, making it suitable for a wide range of applications.

Low Self-Discharge Rate

When not in use, the SR621SW loses its charge very slowly, allowing it to remain functional for years in storage or in devices used only occasionally. This feature is especially beneficial for backup or intermittently operated equipment.

Consistent Performance

The SR621SW provides dependable power output from start to finish, minimizing even slight voltage fluctuations that could affect sensitive devices. This consistency is critical for precision instruments like timepieces and diagnostic tools.

Eco-Friendly Chemistry

Silver oxide cells are considered more environmentally responsible compared to some other battery chemistries. When properly recycled or disposed of, the SR621SW’s impact on the environment can be greatly reduced.

Broad Compatibility

The SR621SW is compatible with a wide variety of brands and models, making it a versatile replacement option for numerous small electronic devices.

Primary (Non-Rechargeable) Cell

As a non-rechargeable primary battery, the SR621SW requires no charging equipment. Once depleted, it can be easily replaced to ensure the device continues operating without interruption.

Applications

The SR621SW battery is used in a wide range of industries and electronic devices thanks to its compact size, stable voltage output, and dependable performance. Below are some of its most common applications:

Watches and Clocks

Widely used in both analog and digital timepieces, the SR621SW is ideal for watches, desk clocks, and other precision timekeeping devices. Its consistent voltage and long shelf life help maintain accurate time over extended periods without frequent battery changes.

Calculators and Small Electronics

This battery is a reliable power source for portable electronics such as calculators, digital thermometers, and similar devices. Its slim profile and stable output make it easy to integrate into a variety of compact gadgets.

Medical Devices

Many healthcare tools—like glucose monitors, blood pressure meters, and hearing aids—rely on the SR621SW. Its high energy density and long storage life make it well-suited for powering critical equipment where reliability can directly impact patient safety.

Wearable Technology

Fitness trackers, smartwatches, and other wearable electronics often use the SR621SW. Its lightweight build and small size make it perfect for powering features such as heart rate monitoring, activity tracking, and notification alerts in compact devices.

Remote Controls and Key Fobs

From TV remotes and air conditioner controllers to garage door openers, car key fobs, and electronic locks, the SR621SW ensures these devices operate reliably with consistent voltage output.

Electronic Toys and Games

Handheld games and electronic toys often run on SR621SW batteries. Their compact design and steady performance deliver hours of uninterrupted fun for both children and adults.

Backup Power for Electronics

The SR621SW can serve as backup power for small sensors, emergency lights, and data-retention systems. Its long shelf life ensures readiness during power outages or disruptions.

Consumer Electronics Accessories

Accessories such as flashlights, laser pointers, and certain digital camera components (like memory card backup systems) benefit from the SR621SW’s reliability, compact dimensions, and ease of replacement.

Final Verdict

The SR621SW battery delivers dependable, versatile power for a wide range of compact devices. With its stable voltage output, long shelf life, and small form factor, it has become an essential choice for precision instruments, medical equipment, and consumer electronics. Whether in watches, hearing aids, or other miniature gadgets, the SR621SW and its equivalents provide consistent performance and uninterrupted functionality. Combining accuracy, durability, and compact design, these batteries supply long-lasting power where it matters most—enhancing the reliability of the technology we use every day.

Frequently Ask Questions

What Battery Can I Use Instead of SR621SW?

A direct replacement for the SR621SW is the 364 battery. It shares the same size (6.8 mm diameter × 2.1 mm height), the same voltage (1.55 V), and the same silver oxide chemistry. Both offer reliable, consistent performance in small electronics such as watches, calculators, and similar devices.

Is SR621SW the Same as 377?

No, the SR621SW and the 377 are not the same battery type.

Is SR621 the Same as 364?

Yes—both the 364 and SR621SW are silver oxide batteries with nearly identical measurements (6.8 mm × 2.1 mm) and the same nominal voltage of 1.55 V. Because of this, they are generally interchangeable in most devices.

Are SR and LR Batteries Interchangeable?

While SR44 and LR44 batteries are physically the same size and shape, their performance differs. LR batteries (alkaline) have a sloping discharge curve, meaning their voltage drops steadily over time, which can cause performance issues in some devices. SR batteries (silver oxide) maintain a more stable voltage until the end of their lifespan.

What Does 377 Mean on a Battery?

A 377 battery is a small silver oxide button cell used in many compact electronics. Known for its steady voltage and long shelf life compared to other chemistries, it’s commonly found in precision devices like watches.

What Is the Difference Between 377 and SR626?

If you’re replacing a basic watch battery, the SR626SW is a budget-friendly choice from reputable third-party brands. For longer shelf life and stronger performance—especially toward the end of the battery’s life—consider premium options like the Energizer 377/376.

What Is a 377 Battery Used For?

The Maxell Coin Cell 377 (SR626SW) is most commonly used as a watch battery replacement. It can also power other small devices such as pagers, memory backup systems, security gadgets, and handheld electronics.

What Is the Difference Between SR and LR Watch Batteries?

The first letter(s) indicate the battery chemistry:

• LR – Alkaline (disposable)
• CR – Lithium (disposable)
• SR – Silver Oxide (contains heavy metals)
• P – Rechargeable (contains heavy metals and/or mercury)

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