Casio · Watches
Casio W-800HG battery
1 × 3V lithium coin cell
How to replace it
| Notes | Case-back service typically required; water resistance should be retested after opening. |
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Important
- Official Casio US manual index → module 3092; OWS CR2025. Distinct from current W-800H module 3240.
- W-800H current support lists module 3240; W-800HG lists module 3092. Do not interchange batteries across those SKUs without checking the caseback.
Sources
Helpful for this device
Optional tools for opening, testing or charging — separate from the battery answer.
- Fluke 101 Digital Multimeter
Accurate open-circuit voltage and basic electrical checks
- Klein Tools MM400 Multimeter
General DC voltage checks including battery terminals
- Digital multimeter
Measure open-circuit voltage and general electronics checks
New battery but still not working?
A fresh 1 × CR2025 should restore Casio W-800HG if the battery was the problem. Work through the checks below before replacing the device.
- Check the battery type
This device needs 1 × CR2025 (lithium). Same size does not always mean the same battery.
- Check known model-specific issues
Official Casio US manual index → module 3092; OWS CR2025. Distinct from current W-800H module 3240. W-800H current support lists module 3240; W-800HG lists module 3092. Do not interchange batteries across those SKUs without checking the caseback.
- Confirm the battery itself
For most coin cells, fitting a known-good fresh cell of the correct code is simpler than capacity testing.
- Still not responding?
If a correct, fresh battery installed properly does not restore the device, the fault may be elsewhere — the device may need service or replacement.