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What Is an SR920SW Battery?

SR indicates silver-oxide chemistry; 9 stands for ~9.5 mm diameter; 20 denotes ~2.0 mm height; and SW marks the low-drain variant best suited for continuous, steady current draw. Typical capacity is 40–45 mAh depending on brand.

Technical Specifications

Key Features

• Flat discharge curve for accurate timekeeping.
• Low self-discharge; long shelf life (3–5 years).
• Leak-resistant sealing for safety.
• Mercury-free and RoHS compliant.
• Compact and lightweight, ideal for small devices.

Applications

• Analog watches (Casio, Citizen, Seiko, Omega, Timex)
• Calculators and measuring tools
• Thermometers, glucometers
• Mini LED gadgets

How Long Does a SR920SW Battery Last?

In most analog watches, an SR920SW lasts around 2–3 years. Power-hungry models or chronographs may reduce this to about 18 months, while simple watches with low-drain movements may last up to 4 years. Watch functions such as lighting or alarms are better suited for SR920W (high-drain). If your second hand starts moving in two-second intervals, it's a sign the battery is nearly depleted.

How to Replace SR920SW Battery in a Watch?

Tools you'll need: two- or three-prong case-back opener (or a snap-back case knife), case holder, plastic/ESD-safe tweezers, microfiber cloth, dust blower, small Phillips/flat driver (for clamps), silicone gasket grease, and a fresh SR920SW cell (a.k.a. 371).

Safety notes: Work on a clean, soft surface; keep magnets away; don't touch the cell surfaces with bare fingers; and be gentle around the coil/step-motor. If your watch is rated for water resistance, inspect and re-grease the gasket before closing.

Step 1 - Prepare a clean, stable workspace

Lay a microfiber cloth, secure the watch face-down in a case holder, and arrange your tools within reach. This prevents scratches and keeps small screws from wandering.

Step 2 - Open the case back (screw-back or snap-back)

For screw-back cases, fit a two- or three-prong opener into the notches and turn counter-clockwise. For snap-back cases, locate the small notch and gently pry with a case knife. Don't force it-steady, even pressure prevents damage.

Step 3 - Remove and inspect the gasket

Lift the rubber gasket gently with plastic tweezers and note its orientation. Clean lint or debris and check for cracks. Apply a thin film of silicone grease for better sealing.

Step 4 - Release the battery clamp or spring

Many movements secure the coin cell with a small clamp/spring and a tiny screw. Loosen the screw just enough to swing the clamp away-do not fully remove unless necessary.

Step 5 - Remove the old coin cell

Tilt the watch slightly and lift the cell out using plastic/ESD-safe tweezers. Avoid scraping the movement or touching coils. Place the old cell aside for proper recycling.

Step 6 - Check polarity and clean contacts

The positive (+) side (often with branding/engraving) typically faces upward. Use a dust blower and lint-free swab to clear contact pads-no solvents on plastic parts.

Step 7 - Install the new SR920SW (371) cell

Seat the new cell flat in the compartment with the correct polarity, then swing the clamp back and tighten the screw lightly. Do not over-torque. If present, ensure the insulator tab (if any) is positioned correctly.

Step 8 - Refit the gasket, close the case, and test

Lightly grease and seat the gasket, ensuring it isn't twisted or pinched. For screw-backs, thread clockwise and tighten evenly; for snap-backs, press with a case press using flat dies. Reset time/date and observe the second hand for smooth one-second steps.

Compatibility tip: SR920SW equals 371 / SR69 in many brand catalogs. Avoid alkaline LR920 for precision timekeeping due to its sloped discharge curve.

SR920SW vs SR920W

SR920SW Equivalent Batteries

SR920SW vs LR920 (Alkaline Alternative)

Storage & Handling

• Store in a cool, dry place away from sunlight.
• Do not mix new and used cells.
• Never recharge; this is a primary battery.
• Recycle responsibly.

Where to Buy SR920SW

Purchase authentic, fresh-date SR920SW batteries from trusted stores to ensure quality and safety.