Buyer's Guide for the 395 Watch Battery

A watch that has stopped requires a precise and reliable solution. The cause is often a dead battery, which begins the search for the exact replacement model. If your watch needs a 395 watch battery or a related identifier like SR927, you've come to the right place. This guide will help you find the right button cell for your watch, explain the key differences between models, and present a selection of suitable products.

What to Look for When Buying an SR927 Button Cell

Choosing the correct battery is crucial for the longevity and accuracy of your watch. Three factors are particularly important: the battery type, its chemical composition, and the correct identification of the model number.

The Difference Between 395 and 399 Batteries

Although a 399 battery and a 395 battery have the exact same dimensions, they are designed for different applications. The difference lies in their current drain:

• 395 Watch Battery (Low-Drain): This version, often designated as SR927SW, is optimised for watches with a low and constant power demand. This includes classic analogue watches that only move the hands.
• 399 Battery (High-Drain): This version, also known as SR927W, is designed for watches with a higher or fluctuating energy demand. It is suitable for watches with additional features like a backlight, a chronograph (stopwatch), or digital displays.

In many cases, a high-drain battery (399) can replace a low-drain battery (395), but not the other way around. Using a 395 in a watch that requires a 399 can lead to a shortened lifespan.

The Advantages of Silver Oxide Batteries for Watches

For wristwatches, the silver oxide battery is the preferred choice. Unlike less expensive alkaline batteries, it provides a very stable voltage of typically 1.55V throughout its entire life. This consistent power supply is crucial for the precise function of the watch movement. Other advantages include a long shelf life due to low self-discharge and high leak resistance, which protects the watch movement.

Correct Identification: SR57, SR927, and Other Designations

Manufacturers use different codes for the same battery type. The designations 395, 399, SR927, and SR57 battery all refer to button cells with a diameter of 9.5 mm and a height of 2.7 mm. To be certain, check the engraving on your old battery or consult your watch's manual.

Our Watch Battery Recommendations

Based on technical specifications and applications, we have compiled a selection of suitable batteries for you.

DURACELL 395/399 1.5V Silver Oxide - Pack of 1

Why It Stands Out: The Duracell 399 (also usable as a 395) is a versatile solution suitable for a wide range of wristwatches. Its silver oxide chemistry delivers the stable voltage required for the accuracy of precision movements. The Duracell brand is known for its reliable performance.

Advantages:

• Stable Voltage: Delivers a constant 1.5-volt output for precise watch operation.
• Long Lifespan: Designed for reliable performance and low self-discharge.
• High Compatibility: Suitable for devices requiring a 395, 399, or SR57 type battery.
• Convenient Supply: According to the manufacturer, the item shown here is supplied as a 2-pack, providing a spare battery for the future.

Who It's For: Watch owners who need a single, reliable battery for a standard or multi-function watch and appreciate the convenience of an included spare.

View Details for Duracell 395/399

VARTA Batterie Silver Oxide, Knopfzelle, 399, SR57, 1.55V Watch, Retail (10-Pack)

Why It Stands Out: This 10-pack of Varta 399 batteries offers an excellent supply for demanding watches. As a high-drain variant, it is specifically designed for digital watches or chronographs with high energy needs. The bulk pack represents excellent value for money.

Advantages:

• High-Drain Performance: Optimised for watches with additional features like backlights or alarms.
• Consistent Voltage: The 1.55V silver oxide cell ensures a consistently stable power output.
• Bulk Pack: The 10-pack provides a convenient supply for households with multiple watches or for hobbyists.
• Brand Quality: Varta is an established manufacturer known for durable battery solutions.

Who It's For: Watch collectors, jewellers, or electronics hobbyists who regularly need high-drain batteries and want to benefit from the cost savings of a bulk pack.

View Details for Varta 399

VARTA Batterie Silver Oxide, Knopfzelle, 395, SR57, 1.55V Watch, Retail (10-Pack)

Why It Stands Out: This 10-pack of Varta 395 batteries is the ideal choice for owners of classic analogue watches. As a low-drain battery, it is specifically tailored to the low, constant energy demand of simple watch movements, offering maximum lifespan in this application. According to the manufacturer, it has a nominal capacity of 44 mAh.

Advantages:

• Low-Drain Specialisation: Engineered for a long runtime in analogue watches without extra features.
• High Capacity: Offers a nominal capacity of 44 mAh for an extended service life.
• Stable Voltage: The 1.55V voltage remains constant throughout the entire discharge cycle, ensuring timekeeping accuracy.
• Economical Supply: The 10-pack is a cost-effective solution for anyone who owns multiple classic watches.

Who It's For: Ideal for owners and collectors of traditional analogue watches who need a reliable and long-lasting power source and want to stock up.

View Details for Varta 395

Looking for More Options?

If the models presented here don't exactly meet your requirements or if you need a different battery size, you'll find a wider selection in our range. Discover more button cells for a variety of applications.

Discover Our Full Range of Silver Oxide Batteries

Frequently Asked Questions (FAQ)

What is the exact difference between a 395 and a 399 watch battery?

Both battery types have identical dimensions (9.5 mm x 2.7 mm). The main difference lies in their current delivery capability. The 395 (SR927SW) is a "low-drain" battery for simple analogue watches with low power consumption. The 399 (SR927W) is a "high-drain" battery for watches with high energy demands, such as those with backlights, digital displays, or stopwatch functions.

Can I change a watch battery myself?

Changing a watch battery is often possible, but it requires care and the right tools to avoid scratches or damage. Pay attention to the following points:

1. Tools: Use a proper watchmaker's tool to open the case back.
2. Handling: Handle the new battery only by its edges, ideally with non-metallic tweezers. Fingerprints on the contact surfaces can increase resistance.
3. Polarity: Note the orientation of the old battery. Typically, the side with the text (the positive terminal, "+") faces upwards.
4. Gasket: When closing the case, ensure the rubber gasket is correctly seated to maintain water resistance.

What is the lifespan of a silver oxide button cell like the Varta 395?

The lifespan of a silver oxide battery depends heavily on the power consumption of the specific watch. A simple analogue watch uses significantly less power than a frequently used chronograph. However, silver oxide cells are characterised by very low self-discharge, which gives them a long shelf and service life. The actual runtime in a watch can vary from one to several years.