Silver Oxide Batteries

Silver Oxide Batteries (Category Guide)

Silver oxide batteries are primary (non-rechargeable) button/coin cells that deliver a steady 1.55 V, making them ideal for devices that need consistent voltage over time. Common uses include watches, calculators, medical sensors, and small measuring instruments.

When to Choose Silver Oxide

• Use if your device specifies an SR code (e.g., SR626SW, SR44) or calls for 1.55 V button cells.
• Use for precision devices that need stable voltage for accuracy (analog/digital watches, meters, compact medical monitors).
• Choose for long service life in small formats with good leak resistance and 3–5 year shelf life.

When to Avoid

• Avoid if the device requires lithium coin cells (CR2032/CR2025/CR2016) or zinc‑air cells (common in hearing aids); chemistries are not interchangeable.
• Avoid for high-drain or high-peak loads; pick the appropriate W (high-drain) type if available, or a different chemistry if the device specifies it.
• Do not use if you need rechargeable power; silver oxide cells are primary only.

How to Select the Right Cell

1. Match the size/code: Look for the SR code stamped on the old battery or in the manual (e.g., SR626SW). The three digits indicate size.
2. Choose the drain type: SW = low-drain (steady, small loads); W = high-drain (devices with higher current pulses, e.g., some watches with alarms/lighting). Using W where SW is specified can work; the reverse may not.
3. Voltage and chemistry: Prefer SR (silver oxide) over LR (alkaline) when precision or longer life is needed. LR shares the size but has lower, sloping voltage and shorter runtime.
4. Check brand cross-references: Watch numbers like 377/376, 303/357 correspond to SR sizes (see table).
5. Buy fresh stock: Choose cells with recent manufacture or long-dated packaging; store sealed, cool, and dry.

Common Sizes and Cross-References

SR Code	Watch Ref	Drain Type	Alkaline Size (LR)
SR621SW	364	Low	LR621
SR626SW / SR626W	377 / 376	Low / High	LR626
SR920SW / SR920W	371 / 370	Low / High	LR920
SR927SW / SR927W	395 / 399	Low / High	LR927
SR44SW / SR44W	303 / 357	Low / High	LR44
SR916SW	373	Low	LR916

Note: LR cells are dimensionally compatible but offer lower, less stable voltage and shorter life than SR cells.

Performance at a Glance

• Nominal voltage: 1.55 V (flat discharge profile).
• Capacity (typical): ~15–25 mAh (SR621), ~25–30 mAh (SR626), ~45–55 mAh (SR927), ~140–170 mAh (SR44). Actual runtime depends on load.
• Operating temperature: about −10°C to +60°C (14°F to 140°F); best performance at room temperature.
• Shelf life: typically 3–5 years when stored sealed at 15–25°C (59–77°F).

Estimated Runtimes (Typical Use)

• Analog/digital watches: 1–3 years (longer for simple analog, shorter with alarms/illumination).
• Calculators: 2–5 years depending on display brightness and usage.
• Small medical sensors/meters: 6–24 months based on test frequency and backlight use.

Signs of end-of-life include dim backlights, intermittent resets, or timekeeping drift. Replace promptly to avoid leakage from over-discharge.

Silver Oxide vs. Other Button/Coin Cells

Silver Oxide vs. Alkaline (SR vs. LR)

• SR provides a flatter 1.55 V output and typically 1.5–3× longer service life in the same size.
• LR is cheaper but voltage drops steadily; may affect accuracy in watches and meters.

Silver Oxide vs. Lithium Coin (CR)

• Lithium coins (e.g., CR2032) are 3 V and larger; not interchangeable with SR sizes.
• CR cells excel at intermittent high peak loads and broad temperature range; use only if specified.

Silver Oxide vs. Zinc‑Air

• Zinc‑air (1.4 V) dominates modern hearing aids; activated by air and offers high capacity for continuous drain.
• Do not substitute silver oxide for zinc‑air or vice versa unless the device explicitly supports it.

Cost, Availability, and Brands

• Cost: Generally higher than alkaline of the same size due to silver content.
• Availability: Widely available in SR and watch-number formats; check for “0% mercury” labeling (standard in modern cells).

Safety and Handling

• Button battery hazard: Keep out of reach of children and pets. If swallowed or inserted, seek immediate medical attention.
• Do not recharge, short-circuit, puncture, or expose to heat.
• Install with correct polarity; clean contacts if needed.
• Store in original packaging; avoid mixing new and used cells in a device.
• Before disposal, tape terminals to prevent shorting.

Environmental and Recycling

Modern silver oxide cells are mercury-free, but they contain recoverable silver. Recycle through battery drop‑off points or electronic waste programs. Do not discard in household trash.

FAQ

Can I replace an alkaline LR button cell with a silver oxide SR of the same size?

Yes. SR is dimensionally compatible and usually performs better and longer. Replacing SR with LR is possible in some devices but may reduce accuracy and runtime.

What’s the difference between SW and W on SR batteries?

SW indicates low-drain for steady, small loads (e.g., simple analog watches). W indicates high-drain for devices with higher current pulses (e.g., watches with alarms/lighting). Use the type specified by the device.

How do I read watch battery numbers like 377 or 357?

These are industry watch references that map to SR sizes and drain types, e.g., 377 = SR626SW (low-drain), 357 = SR44W (high-drain). Check the cross-reference table or your manual.

Are silver oxide batteries leak-resistant?

They are designed to resist leakage under normal use. Replace promptly at end-of-life and avoid extreme heat or over-discharge to minimize risk.

Do hearing aids use silver oxide?

Most modern hearing aids use zinc‑air cells (sizes 10, 312, 13, 675). Use silver oxide only if your device specifically lists an SR size.