SR626SW Cross Reference Chart: Compatible Battery Equivalents (377, AG4, D377, SR66)

Why Cross References Matter

Understanding battery cross references is not just about comparing part numbers-it's about ensuring your device receives the exact electrical performance it was designed for. Many button cells share the same size but differ in chemistry, discharge behavior, and load capacity. A watch that specifies SR626SW requires the steady 1.55 V output of a silver-oxide cell; installing an AG4 (alkaline) of identical dimensions might make it tick for a while, but voltage drops will soon cause time drift or early stoppage.

That's why cross-reference accuracy matters. It helps you identify the true equivalent across different naming systems-377, SR626SW, SR66-and avoid misleading substitutes. In precision instruments such as watches, medical sensors, and compact meters, matching the right chemistry and drain class is as critical as matching the size itself. In the sections below, you'll find a detailed cross-reference chart and guidance for choosing the correct SR626SW (377) replacement with confidence.

Naming Systems Explained: IEC / JIS / Trade Numbers / Generics

SR626SW Cross Reference Chart (Brand-by-Brand)

The following cross-reference focuses on the low-drain silver-oxide variant used by most analog quartz watches. A separate column lists the high-drain partner where applicable.

Tip: Some distributor listings compress both codes to "377/376." Always open the detail row or check the blister to confirm SW (low-drain) vs W (high-drain).

Size & Voltage Compatibility

SR vs LR vs CR: Don't Confuse Chemistry

• SRxxx = Silver-Oxide (e.g., SR626SW). Best for watches: flat discharge curve, stable 1.55 V.
• LRxxx / AGx = Alkaline (e.g., LR626/AG4). Fits mechanically but sags in voltage; watch may drift or stop early.
• CRxxxx = Lithium coin (e.g., CR2032). Entirely different size families and 3.0 V chemistry-not for SR626 trays.

Online marketplaces often list "AG4 = 377" as a size shortcut. Treat this carefully: AG4 tells you the diameter/height class, not the chemistry. For watches, ask for SR626SW or 377 (silver-oxide).

SW vs W: Low-Drain vs High-Drain (377 vs 376)

If your watch stalls when you press light or alarm, it likely needs the W (high-drain) variant. Conversely, if it's a minimalist three-hand analog, SW maximizes runtime.

Common Mistakes & How to Avoid Them

• Confusing AG4/LR626 with SR626SW: Alkaline is cheaper but not equal; it causes early stoppage and time drift.
• Ignoring "W" vs "SW" suffix: High-drain movements can misstep with SW cells as they age. Follow the movement spec.
• Assuming any "377/376" blister is fine: Look for the suffix or check the datasheet row in the listing.
• Buying stale stock: Old cells may measure 1.55 V no-load but sag under pulse. Source fresh, reputable brands.

How to Choose the Correct Substitute (Step-by-Step)

1. Read the device spec: Caseback, manual, or movement database (e.g., SR626SW or SR626W).
2. Match chemistry: Choose silver-oxide (SR), not alkaline (LR), for watches.
3. Match drain class: SW for low-drain; W for high-drain features (chronograph/alarm/light).
4. Choose a brand: Renata 377/376, Murata SR626SW/W, Energizer 377/376, Maxell SR626SW/W, Panasonic SR626SW/W.
5. Check freshness: Prefer recent production codes and sealed blisters.
6. Install carefully: Observe polarity, clean contacts, and inspect gasket for water-resistance models.

Related Sizes & When They Don't Fit

SR626SW is often confused with neighboring sizes. Here's a quick orientation:

FAQs

Is SR626SW the same as 377?

Yes. 377 is a trade number; SR626SW is the IEC designation for the same low-drain silver-oxide watch cell.

Is AG4 the same as SR626SW?

AG4 indicates a similar size (6.8×2.6 mm class) but typically refers to alkaline chemistry (LR626). For watches, use SR626SW (silver-oxide).

What's the difference between SR626SW and SR626W?

SW = low-drain; W = high-drain. Use SR626W (376) for chronographs/alarms/lights; use SR626SW (377) for simple analog watches.

Can I replace SR626SW with LR626?

Mechanically it fits, but alkaline LR626 has poorer voltage stability. In watches, it leads to drift and early stoppage-use silver-oxide SR626SW/377.

Which brands are most reliable?

Renata (377/376), Murata (SR626SW/SR626W), Energizer (377/376), Maxell (SR626SW/SR626W), Panasonic (SR626SW/SR626W). Stick to reputable sellers for fresh stock.

Conclusion & Buying Tips

SR626SW is the low-drain silver-oxide standard for slim analog watches. Its most common equivalents are 377 (trade) and SR66 (family). Do not confuse it with AG4/LR626 alkaline, which shares the size but not the performance. If your movement calls for SR626W/376, use the high-drain variant to prevent voltage sag during pulses.

For dependable results, match size + chemistry + drain class, choose leading brands, and verify freshness. A correct cross-reference avoids callbacks, improves accuracy, and maximizes service intervals.

BomKey Electronics supplies genuine SR626SW (377) and SR626W (376) watch batteries from Renata, Murata, Energizer, Maxell, Panasonic, and more-backed by fresh inventory and datasheet support for professional repair shops and enthusiasts.