Renata 315 (SR716SW) — Complete Buyer’s Guide, Specs, and Best-Practice Use

Renata 315 (SR716SW) is one of the most widely used silver-oxide button cells in watchmaking. Favored by bench pros and enthusiasts alike, it combines stable 1.55 V output with Swiss build quality to keep analog and multifunction watches running accurately for long stretches. This in-depth guide covers what the 315 is, how it differs from other cells, its typical use cases, installation tips, handling/storage best practices, and the factors that affect real-world runtime so you can choose and maintain it with confidence.

Quick Facts

• Chemistry: Silver-oxide (1.55 V nominal)
• Form factor: SR716SW button cell (approx. 7.9 mm diameter × 1.65 mm height)
• Common use: Analog and multifunction wristwatches, small instruments, compact electronics
• Key traits: Flat discharge curve, low self-discharge, leak-resistant design, mercury-free construction

Why Silver-Oxide for Watches?

Silver-oxide chemistry is a mainstay in watch batteries because it delivers a flat discharge curve: voltage stays close to 1.55 V for most of the cell’s life and only drops near end of life. That stability is ideal for watch circuits that are calibrated for tight voltage windows. Compared with alkaline button cells, silver-oxide cells typically provide longer, steadier service and better resistance to voltage sag in low-to-moderate drain applications.

Understanding the Code: SR716SW

The code printed on many watch cells follows a consistent pattern:

• SR = silver-oxide chemistry (“S”ilver, “R”ound)
• 716 ≈ size family (about 7.9 mm diameter × 1.65 mm height)
• SW = “low-drain” watch use (often suited to continuous low current typical of analog movements)

In practice, the Renata 315’s dimensions help it fit numerous slim watch cases where height is at a premium. If you’re replacing a battery, matching SR716SW (or the manufacturer’s 315 callout) is the most reliable way to maintain proper clearance and case sealing.

Key Advantages of Renata 315

1. Stable Voltage for Accurate Timekeeping: The consistent 1.55 V output helps keep mechanical-quartz hybrids and analog watches running on-spec.
2. Swiss-Made Consistency: Tight quality control and uniform cell construction reduce variance across batches, which is crucial for watch service operations.
3. Low Self-Discharge: Prolonged shelf life means you can stock spares without worrying about premature depletion.
4. Leak-Resistant Design: Formulation and seals are designed to resist electrolyte leakage that could damage delicate movements.
5. Mercury-Free & RoHS-Compliant: Environmentally responsible build with no added mercury.

Typical Applications

Renata 315 is primarily chosen for:

• Analog wristwatches: Classic three-hand watches and date models with modest power draw.
• Compact timekeeping electronics: Small clocks, timers, and thin instruments designed for SR716SW height.
• Slim medical/fitness devices: When specified by the device maker and size is compatible.

Runtime: What to Expect

Exact runtime depends on the watch movement, complications (e.g., date, alarm), ambient temperature, lubrication state, and seal condition. A healthy analog movement that calls for SR716SW will generally see a predictable service interval. If a replacement 315 seems to “die early,” it’s often a sign the movement needs cleaning, regulation, or seal replacement rather than a cell issue.

Sizing and Fit — Why It Matters

Button-cell sizes are precise. A fraction of a millimeter in height can affect caseback closure and water-resistance. The Renata 315’s height (~1.65 mm) makes it ideal for ultra-slim cases that can’t accept taller cells. Always verify the reference engraved inside the caseback or in the watch’s documentation before substituting another size family.

SW vs. W (Low- vs. High-Drain)

Many silver-oxide cells are offered in low-drain (SW) and high-drain (W) variants. The 315 is traditionally specified as SW, aligning with the needs of analog movements. High-drain cells are intended for devices that demand short bursts of higher current (e.g., certain digital functions or alarms). For most watches that specify 315/SR716SW, matching the SW type preserves expected runtime and accuracy.

Handling and Installation Tips

• Use non-metal tweezers or finger cots: Prevents shorting and keeps skin oils off contacts.
• Check polarity carefully: The “+” side typically faces outward; confirm against the old cell or movement diagram.
• Inspect the gasket: If the caseback seal looks flattened or cracked, replace it to maintain water-resistance.
• Clean light corrosion: Use appropriate, gentle contact cleaners designed for watch work.
• Perform a current-draw test: If available, verify the movement’s draw is within spec before closing the case.

Storage Best Practices

• Keep cells in original packaging until use.
• Store in a cool, dry environment away from direct sunlight and heat sources.
• Avoid mixing new and used cells in the same container.
• Do not freeze; extreme cold can compromise seals and performance.

End-of-Life and Replacement Cues

Common signs that it’s time to replace a 315 include a watch running slow, second-hand “stepping” in larger increments (on some movements), or intermittent stops. Replace promptly to prevent leakage from an exhausted cell. Dispose of used cells responsibly in accordance with local recycling guidance.

Troubleshooting After Replacement

• Watch still stops: The movement may be dirty or dry; consider a professional service.
• Alarm/date misbehaving: Re-initialize functions according to the manual; low-drain cells can be stressed by repeated high-load cycles.
• Water-resistance lost: Replace gaskets and pressure-test if the watch will be exposed to water.

Spec Snapshot (Renata 315)

Parameter	Typical Value/Note
Chemistry	Silver-oxide (mercury-free)
Nominal Voltage	1.55 V
Size Code	SR716SW (approx. 7.9 mm × 1.65 mm)
Use Profile	Low-drain analog watch movements
Key Features	Flat discharge, low self-discharge, leak-resistant, Swiss quality

Best Practices for Watch Pros and Retailers

• Date-code rotation: Organize stock to use the oldest cells first while staying well within shelf-life windows.
• Movement assessment: Offer a quick current-draw check with every battery swap to preempt comebacks.
• Seal maintenance: Keep common gasket sizes on hand; reseal on the spot.
• Customer guidance: Remind owners to avoid moisture exposure if the watch isn’t rated water-resistant after service.

Bottom Line

The Renata 315 (SR716SW) is a go-to choice for slim analog watches that need stable, long-lived 1.55 V power. Its combination of precise sizing, consistent quality, and mercury-free construction makes it an easy recommendation for professional benches and DIY replacements alike. Match the SR716SW size and SW drain profile, install with clean technique, and your timepiece should reward you with accurate, dependable operation until the next scheduled service.