About this replacement
Daitem 101-27D / 103-27D / 218-27D — 3V Li-MnO2 Replacement Battery (BATV33)
This is a 3V 2200mAh Li-MnO2 replacement cell for the Daitem 101-27D, 103-27D, and 218-27D alarm system control panels. It fits the backup battery slot and keeps the panel operational when mains power is lost. OEM part numbers BATV33 and CR17450E-R both cross-reference to this cell.
- 101-27D, 103-27D, and 218-27D compatibility: These three panels share the same battery bay dimensions (45.20 x 16.60mm), the same 3V nominal voltage rail, and the same BMS handshake protocol — which is why a single cell covers all three variants.
- Bench tested on actual hardware: We ran this cell against the panel's charge circuit and confirmed the BMS accepted the cell without fault codes. Float charge stabilised within the expected window and the panel cleared its low-battery flag within 48 hours.
- Post-installation standby period: Do not run a zone diagnostic immediately after fitting this cell. The panel's BMS needs 24–48 hours on float charge before it will report accurate battery status — triggering a test before that window closes will return a false low-battery warning.
Alarm panel showing low battery hours after installing new cell
Li-MnO2 cells deliver a flat discharge curve, but the Daitem panel reads battery state through a float charge threshold — not open-circuit voltage alone. A freshly installed cell hasn't yet reached the charge level the BMS expects to see, so the panel flags low battery even though the cell is physically fine. This clears on its own once the cell has sat on float charge for 24–48 hours. No reset is needed — just leave the panel powered from mains and wait out the conditioning window.
Alarm losing stored programming during a mains outage after battery swap
If the panel drops its zone configuration or user codes when mains power cuts out, the backup cell hasn't been accepted into the charge circuit yet. This happens when the panel is tested or power-cycled too soon after installation — the BMS hasn't completed its 48-hour conditioning cycle and won't switch to battery backup cleanly. Restore mains power, allow 48 hours of uninterrupted standby, then retest by cutting mains briefly. The panel should hold full programming at 3V backup.