About this replacement
DSC PG9920 Repeater — 4.8V Ni-MH Replacement Battery (BATT1.3-4.8V)
This is a 4.8V, 1500mAh Ni-MH battery for the DSC PG9920 wireless repeater and compatible DSC alarm system components. The PG9920 extends wireless range between your control panel and remote sensors — when this battery degrades, that link becomes unreliable or drops entirely. Fits the PG9920 Repeater, wireless DSC-56, WP8010-SP, and Central WP8010 series panels.
- PG9920 and WP8010 platform compatibility: These units share a 4.8V NiMH cell format with a matched connector and BMS charge acceptance profile. Swapping a mismatched chemistry or voltage will cause the panel to reject the cell or report a persistent fault condition.
- Bench tested on actual hardware: We ran this cell through charge acceptance on a DSC-compatible test rig. The BMS accepted the cell without faulting, and float charge stabilised within the expected window. No false low-battery flags were thrown after the conditioning period completed.
- Post-installation hold period: Do not run a zone or diagnostic test immediately after fitting this cell. The DSC panel needs 24–48 hours on float charge before its BMS reports accurate battery status. Testing too early will generate a low-battery alert even on a fully functional new cell.
Why the PG9920 loses wireless coverage after a battery swap
The PG9920 is a powered repeater — it actively retransmits signals rather than passively relaying them. When the backup cell voltage drops below the repeater's operating threshold, the unit stops retransmitting even if mains power is present. After fitting a new cell, the repeater needs time to stabilise at full charge before it resumes normal range performance. If sensors at the edge of coverage are still dropping after 48 hours, check that the new cell is seated firmly and the connector is fully engaged.
Panel shows low battery fault hours after installing a new cell
This is a BMS reporting lag, not a faulty battery. DSC panels sample backup cell voltage on a fixed cycle, and a freshly installed NiMH cell often reads below the panel's acceptance threshold until it has completed an initial charge cycle. The fault clears itself once the cell reaches float voltage — typically around 5.5–5.8V across a fully charged 4.8V NiMH pack. Leave the system powered for a full 48 hours, then check panel status again before assuming the cell is defective.