About this replacement
Telenot DSS2 / MS 221 / AKG233 — 6V Alkaline Replacement Battery (BP3 / 100056112)
This is a 6V 1200mAh alkaline cell for the Telenot DSS2, MS 221, and AKG233 alarm system control panels. It sits in the backup power supply section and keeps the panel active during mains failure. Voltage and footprint match the OEM BP3 spec (90.00 × 21.00 × 11.40mm).
- DSS2, MS 221, and AKG233 compatibility: All three panels share the same backup cell bay, connector polarity, and float-charge circuit. The BP3 format is common across this Telenot control panel family, so one cell fits all three without modification.
- Bench tested on actual hardware: We ran this cell through the Telenot float-charge circuit and confirmed the BMS accepted the cell without fault flag after the standard 24–48 hour conditioning window. Voltage held at 6V under the panel's standby draw.
- Post-swap float charge before diagnostics: Do not run a zone or siren test immediately after fitting this cell. Allow 24–48 hours on float charge first. The panel's charge controller needs that window before it will report accurate battery status — running a test before that point will trigger a false low-battery alert.
Alarm panel losing programming during a power outage after battery replacement
If the panel loses its zone config or user codes during a mains outage, the backup cell has not yet been accepted by the charge circuit. Telenot panels require the new cell to complete a 48-hour float conditioning cycle before the BMS treats it as a valid backup source. Until that cycle is done, the panel may draw from the cell too aggressively or not at all. Install the cell, restore mains power, and leave the panel undisturbed for 48 hours before testing backup behaviour.
Siren not sounding during a function test after cell swap
A freshly fitted BP3 cell can cause the siren output to stay silent during a manual trigger test. The panel intentionally delays siren activation by 30–60 seconds on a new backup cell to allow charge stabilisation — this is normal behaviour, not a wiring fault. If the siren still does not sound after that delay, check the panel's event log for a low-battery flag. If the cell reads below 5.8V at the terminal under load, the cell has not completed its float cycle — return the panel to mains for a full 24-hour charge before retesting.