Renata 335 (SR512SW) Silver‑Oxide Watch Battery

The Renata 335 is an ultra-thin, low-drain silver-oxide button cell designed for slim analog watches that specify SR512SW. It delivers stable 1.55 V output in a compact profile, supporting accurate timekeeping without adding thickness.

Key Specs

• Chemistry: Silver‑oxide (mercury‑free)
• Nominal voltage: 1.55 V
• Size (IEC): SR512SW
• Dimensions: ≈ 5.8 mm diameter × ≈ 1.2–1.25 mm height
• Drain type: Low‑drain (SW) for analog movements
• Compliance: RoHS; mercury‑free construction

When to Choose This Cell

• Use if: Your watch (typically a slim 2–3 hand analog) calls for 335 or SR512SW and has very limited clearance.
• Avoid if: The device specifies a different size (e.g., SR516SW/317, SR521SW/379) or requires high‑drain power for chronographs, alarms, lighting, or digital functions.

Compatibility & Cross‑References

Match the exact code on your old cell or in the service manual.

• Primary codes: 335, SR512SW
• Also seen as: Renata 335, Energizer 335, Maxell SR512SW, Panasonic SR512SW, Sony SR512SW, Varta V335

Do not substitute nearby sizes such as SR516SW (317) or SR521SW (379); they differ in height and will not fit correctly.

Performance Expectations

• Runtime: Typically ~6–12 months in simple low‑drain analog watches; shorter with added complications or aging movements.
• Discharge behavior: Flat voltage curve helps maintain consistent timekeeping until end of life.
• Shelf life: Commonly several years when stored sealed in original packaging at room temperature.

Installation Tips

• Confirm the required size: look for 335 or SR512SW on the old cell or caseback.
• Handle with plastic or non‑marring tweezers; avoid shorting the cell with metal tools.
• Check polarity and seating; ensure battery tabs or springs make clean contact.
• Inspect caseback gasket and replace if water resistance matters.
• If the watch still stops or resets, the movement may need cleaning or service.

Storage & Care

• Keep sealed in original packaging until use.
• Store cool and dry (about 50–77 °F / 10–25 °C); avoid heat and humidity.
• Do not refrigerate or freeze; rotate stock by date code.

Safety & Disposal

• Button cells present a choking and ingestion hazard—keep away from children and pets.
• Do not recharge, puncture, or incinerate.
• Recycle in accordance with local regulations; many jewelers and electronics stores offer collection.

FAQ

Is 335 the same as SR512SW?

Yes. 335 is a common manufacturer code for the IEC size SR512SW.

Can I replace 335 with 317 (SR516SW) or 379 (SR521SW)?

No. These cells are taller and will not fit properly; always match SR512SW/335 for this size.

Do I need a high‑drain (W) cell?

Not for simple analog watches. The 335 is low‑drain (SW). Watches with alarms, lights, or chronograph modules may require high‑ or multi‑drain cells, but those typically use different sizes.

Is there an alkaline equivalent?

No practical alkaline equivalent exists in this ultra‑thin size. Silver‑oxide provides better voltage stability and runtime for watches.

How long will it last in my watch?

Plan for roughly 6–12 months in low‑drain analog models; actual life varies with movement condition, temperature, and features.