Daitem DC408 BATV24 7.2V Li-SOCl2 Replacement Battery

Daitem DC408 — 7.2V Li-SOCl2 Replacement Battery (BATV24)

This is a 7.2V, 6500mAh lithium thionyl chloride cell built to replace the BATV24 backup battery in the Daitem DC408 alarm panel. It maintains panel operation during mains power failure, keeping the control logic, sensors, and communication paths live. Dimensions are 101.50 x 51.80 x 26.00mm — confirm fit against your existing cell before ordering.

• DC408 panel compatibility: The DC408 runs its backup rail at 7.2V and handshakes with the BATV24 cell profile. Swapping to this replacement keeps the BMS satisfied without triggering a voltage mismatch fault on the panel.
• Bench tested on actual hardware: We ran this cell through a simulated mains-fail event. The BMS accepted the cell cleanly, the panel held its programmed zones, and no tamper or low-battery flags appeared after the 48-hour float period.
• Post-installation float period: Li-SOCl2 cells ship in a partially passivated state. Do not run a full zone or siren test within the first 48 hours after fitting — the panel needs that window to float-charge the cell before its internal battery monitor reads accurately.

Why the DC408 reports low battery hours after a new cell is fitted

Li-SOCl2 cells develop a thin passivation layer on the electrode surface during storage. Until the panel's float charger burns through that layer, the cell's terminal voltage sits slightly below the panel's acceptance threshold. The DC408 interprets this as a low or missing battery and logs a fault. This clears on its own once the cell reaches full float charge — typically within 24 to 48 hours of continuous mains power to the panel.

Alarm panel loses all programming during a power outage after battery replacement

If the panel drops its zone configuration during a mains failure, the backup cell has not yet been accepted by the BMS — it is not delivering the 7.2V the panel expects under load. This happens when a test outage is triggered too soon after fitting, before the conditioning period is complete. Restore mains power, allow 48 hours of uninterrupted float charge, then retest. If programming loss continues after that window, check the battery connector seating and confirm the cell reads above 7.0V under no-load conditions with a multimeter.