Seiko names the battery for each quartz watch in the instruction booklet for its caliber, and its customer service page says that caliber code is on the case back.
The battery it takes
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Finding the caliber
The case back carries a marking such as 5M62-0A00. Seiko’s Kinetic booklet explains that the caliber is the four characters to the left of the hyphen, 5M62 in that example.
SW or W: two cells of one size
The letters after the size matter. Renata’s data sheets rate its 377 (SR626SW) as low drain and its 376 (SR626W) as high drain, at the same 6.8 x 2.6 mm.
Energizer’s silver oxide manual says low drain cells are made for long, steady use in analog watches, and high drain ones for watches with alarms or backlights. Seiko’s booklets give SR927SW for some calibers and SR927W for others, so match the full code.
Seiko batteries by how many calibers use them
| Battery | What it is | Calibers |
|---|---|---|
| SR920SW | 9.5 x 2 mm silver oxide, 1.55 V (Renata 371) | 20 |
| SR927W | 9.5 x 2.7 mm silver oxide, 1.55 V (Renata 399) | 10 |
| SR927SW | 9.5 x 2.7 mm silver oxide, 1.55 V (Renata 395) | 9 |
| CR2032 | 20 x 3.2 mm lithium coin, 3 V | 5 |
| CR2412 | Lithium coin, 3 V | 4 |
| SR1130W | 11.6 x 3.05 mm silver oxide, 1.55 V (Renata 389) | 4 |
| CR2016 | 20 x 1.6 mm lithium coin, 3 V | 3 |
| CR2025 | 20 x 2.5 mm lithium coin, 3 V | 3 |
| SR936SW | 9.5 x 3.6 mm silver oxide, 1.55 V (Renata 394) | 3 |
| CR1612 | Lithium coin, 3 V | 2 |
| SR43SW | 11.6 x 4.2 mm silver oxide, 1.55 V (Renata 301) | 2 |
| SR621SW | 6.8 x 2.1 mm silver oxide, 1.55 V (Renata 364) | 2 |
| SR626SW | 6.8 x 2.6 mm silver oxide, 1.55 V (Renata 377) | 2 |
| SR920W | 9.5 x 2 mm silver oxide, 1.55 V (Renata 370) | 2 |
| CR1025 | 10 x 2.5 mm lithium coin, 3 V | 1 |
| CR2012 | 20 x 1.2 mm lithium coin, 3 V | 1 |
| SR43W | 11.6 x 4.2 mm silver oxide, 1.55 V (Renata 386) | 1 |
| SR521SW | 5.8 x 2.1 mm silver oxide, 1.55 V (Renata 379) | 1 |
| SR916SW | 9.5 x 1.6 mm silver oxide, 1.55 V (Renata 373) | 1 |
Counted from the booklets read. CR1612 and CR2412 are as Seiko names them; sizes come from Renata’s list and the coin cell makers’ sheets.
How long a battery lasts
One booklet, shared by calibers 7C46, 7N36, 7N85 and V736, gives an approximate life for each: about 5 years for the 7C46, 4 for the 7N36 and V736, and 2 for the 7N85.
Solar and Kinetic calibers
| Kind | Calibers | How it’s powered |
|---|---|---|
| Solar | V110, V111, V114, V115, V116, V117, V137, V145, V147, V157, V158, V181, V182 and V187 | Light, stored in a rechargeable cell |
| Kinetic | 5M62 and 5M63 | Arm movement, stored in a rechargeable cell |
| Kinetic | 3M22, 5M42 and 5M43 | Arm movement, stored in a capacitor |
From Seiko’s solar and Kinetic instruction booklets.
Swallowed button batteries
The National Capital Poison Center says that if anyone swallows a battery, immediately call the 24-hour National Battery Ingestion Hotline at 1-800-498-8666 or your poison center at 1-800-222-1222. Don’t delay. Immediate treatment decreases severity.