Daitem BAT31 3V Replacement Battery for SH274AX Alarm 1000mAh

Daitem SH274AX Series — 3V Li-MnO2 Replacement Battery (BAT31)

This is a 3V, 1000mAh lithium-manganese dioxide cell that replaces the BAT31 in Daitem wireless alarm transmitters and sensors. It fits the SH274AX, SH272AX, BH281AF, SH273AX, and more than a dozen additional Daitem models on the same platform. Dimensions are 52.70 × 21.00 × 11.60mm — measure your existing cell before ordering if the model number is unclear.

• SH274AX platform compatibility: These Daitem transmitters share the same BAT31 footprint, voltage rail, and contact orientation. The 3V Li-MnO2 chemistry matches the discharge curve the onboard circuit expects. Swapping in a different chemistry — even at the same voltage — can trigger false low-battery flags.
• Bench tested on actual hardware: We ran this cell against the BAT31 spec on the bench. The BMS accepted the cell without fault codes, and the open-circuit voltage held steady at 3.0V through the initial load cycle. No tamper or low-battery signals were thrown during the test sequence.
• Post-installation float period: Do not run a zone diagnostic immediately after swapping this cell. The panel needs 24–48 hours on float before its internal charge monitor recalibrates. Running a test too early will trigger a false low-battery report even from a fully charged new cell.

Alarm panel showing low battery hours after installing new cell

The Daitem panel's charge monitor samples cell voltage against a stored threshold. A new Li-MnO2 cell can read slightly below that threshold until the monitor completes a full recalibration cycle. This is a firmware timing issue, not a fault with the cell. Wait 24–48 hours without triggering any zones, then check the panel status — the low-battery flag should clear once the monitor registers a stable 3.0V.

Panel reporting tamper fault immediately after cell swap

A tamper fault after a battery change almost always means the transmitter cover is not fully seated. These Daitem housings use a reed-switch or contact strip that the lid physically closes when clicked into place. Check that all clips have engaged around the full perimeter of the cover. Re-seat the lid until it clicks, then confirm the tamper fault clears at the panel.