Smart home sensors
RuuviTag battery
1 × 3V lithium coin cell
Ruuvi’s tech spec lists a 1000 mAh CR2477 for RuuviTag and CR2477T for RuuviTag Pro — both user-replaceable. Lift the lid / twist the Pro cover, swap the coin cell, reseat the o-ring. Not CR2450.
How to replace it
| Compartment | Inside the sensor enclosure (lift lid / twist back cover) |
|---|---|
| How to open | White RuuviTag: lift the top lid, remove the circuit board, push the CR2477 out of the holder, insert a new CR2477, reseat the board and o-ring, close the lid. RuuviTag Pro: rotate the back cover counter-clockwise, lift the board, replace the coin cell in the cover, reseat and close clockwise with wings aligned. |
| Orientation | As seated in the battery holder / back-cover pocket |
| Access | Tool-free |
| Notes | Avoid fingerprints on the cell. Confirm o-ring seating before closing. For −40…+85 °C use CR2477T; standard CR2477 is rated about −20…+70 °C with the sensor. |
Important
- CR2477 is much thicker than CR2450 — not a drop-in swap.
- RuuviTag Pro’s factory CR2477T is the same 24.5×7.7 mm family with a wider temperature rating — confirm the marking on the cell you remove.
- Keep coin cells away from children.
- Do not force a Pro back cover 180° wrong — can tear board components.
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 × CR2477 should restore Ruuvi RuuviTag if the battery was the problem. Work through the checks below before replacing the device.
- Check orientation
Confirm the cell is seated correctly: As seated in the battery holder / back-cover pocket
- Check the battery type
This device needs 1 × CR2477 (lithium). Rechargeable cells are not supported for this device. Same size does not always mean the same battery.
- Check known model-specific issues
CR2477 is much thicker than CR2450 — not a drop-in swap. RuuviTag Pro’s factory CR2477T is the same 24.5×7.7 mm family with a wider temperature rating — confirm the marking on the cell you remove. Keep coin cells away from children.
- 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.
Replacing the device?
Ruuvi RuuviTag is still sold new. Only consider a replacement if the checks above did not help.
Need to replace the device?
Ruuvi RuuviTag is still sold new. Only buy another if a fresh battery and the checks above did not help.