Renata 377 (SR626SW) Silver‑Oxide Watch Battery

The Renata 377 (SR626SW) is a low‑drain, 1.55 V silver‑oxide button cell commonly used in analog quartz watches without power‑hungry features. It maintains a steady voltage, is mercury‑free, and fits the 6.8 × 2.6 mm footprint used by many timepieces.

Key specifications

Chemistry	Silver‑oxide (mercury‑free)
Nominal voltage	1.55 V
Size (D × H)	6.8 mm × 2.6 mm
Drain type	SW (low‑drain)
Typical capacity	~25–30 mAh (varies by load and brand)
Compliance	Mercury‑free, RoHS

Use this battery if…

• Your watch or manual specifies 377 or SR626SW.
• You have a simple analog quartz watch (no continuous backlight, alarms, or power‑hungry complications).
• You want longer life and steadier voltage than size‑equivalent alkaline cells.

Avoid or consider alternatives if…

• Your watch specifies 376 or SR626W (high‑drain). Use the high‑drain variant instead for chronographs, alarms, or demanding movements.
• You are considering LR626/AG4. These are alkaline size‑equivalents with shorter life and less stable voltage; use only as an emergency substitute.

Compatibility and cross‑references

Common name	377
IEC	SR626
JIS	SR626SW
Size‑equivalent alkaline (not preferred)	LR626, AG4

Note: 376 (SR626W) shares the same size but is the high‑drain version. Follow the marking inside your caseback or the watch manual.

Expected runtime

In a typical analog quartz movement drawing ~1–2 µA, a 377 cell usually lasts about 18–36 months. Chronographs, date complications, or cold environments can shorten life.

Installation tips

• Match the code on your old cell or the manual: 377 / SR626SW.
• Observe polarity; the flat side is usually the positive (+) terminal.
• Handle with plastic tweezers or gloves to avoid shorting and skin oils.
• Inspect and replace the caseback gasket if compressed or cracked to maintain water resistance.
• After closing the caseback, check timekeeping and any date/complications for correct operation.

Pros and cons

• Pros: Stable 1.55 V output, longer life vs. alkaline, mercury‑free, widely available.
• Cons: Not ideal for high‑drain functions (use 376/SR626W), smaller capacity than larger coin cells.

Storage and safety

• Store in original packaging at room temperature; avoid heat and humidity. Shelf life is typically up to 5 years when sealed.
• Keep away from children. Button batteries are hazardous if swallowed—seek immediate medical help if ingestion is suspected.
• Recycle at an approved battery collection point; do not incinerate.

FAQ

What is the difference between 377 and 376?

Both share the same size (SR626). 377/SR626SW is low‑drain for standard analog watches; 376/SR626W is high‑drain for watches with higher current draw (e.g., chronographs, alarms). Use what the watch specifies.

Can I use LR626 or AG4 instead of 377?

They are size‑equivalent alkaline cells, but they have shorter life and a less stable voltage curve. Use silver‑oxide 377/SR626SW for best performance.

How long will a Renata 377 last in my watch?

Typically 1.5–3 years in a simple analog quartz watch. Actual life depends on the movement, features, and temperature.

Is the 377 battery rechargeable?

No. It is a primary (single‑use) silver‑oxide cell. Do not attempt to recharge.

How do I know it’s time to replace the battery?

Common signs include the second hand jumping in 2–4 second steps, loss of timekeeping accuracy, or complications (date/chronograph) failing to operate.