Visonic BGS-220 Replacement Battery LIB2A6 3.7V 2700mAh

Visonic BGS-220 / B3G-220 / VLE-320 — 3.7V Li-Polymer Replacement Battery (LIB2A6)

This is a 3.7V, 2700mAh Li-Polymer replacement cell for the Visonic BGS-220, B3G-220, and Transmitter VLE-320 wireless alarm control system. It slots into the portable keypad that handles remote arming, disarming, and zone control for the BGS-220 platform. Capacity is 2700mAh (9.99Wh), matching the original LIB2A6 specification.

• BGS-220, B3G-220, and VLE-320 platform fit: All three devices run the same 3.7V Li-Polymer power rail and share the LIB2A6 cell format. The connector pinout and physical footprint (62 × 50 × 7.30mm) are consistent across the platform, so no wiring modification is needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the BGS-220 platform. The BMS accepted the cell, completed a full charge cycle, and transitioned to float without flagging a fault. No voltage sag was detected at the panel's communication threshold.
• Post-install float charge before diagnostics: Do not run a zone test immediately after fitting this cell. Allow 24–48 hours on float charge before triggering any diagnostic. A new Li-Polymer cell that hasn't reached full float charge will cause the panel to report a low battery condition during the test — not a fault with the cell itself.

Why the BGS-220 panel flags low battery hours after a fresh cell is installed

The BGS-220 panel monitors battery state via a voltage threshold comparison, not a capacity gauge. A new Li-Polymer cell ships at partial charge — typically 3.3–3.5V — which can sit below the panel's "battery OK" threshold of around 3.6–3.7V. The panel will continue to flag low battery until the cell reaches full float voltage after a complete charge cycle. This is normal behaviour and clears on its own once the cell is fully charged.

BGS-220 losing stored programming during a mains outage after battery replacement

If the panel drops programming during a mains outage shortly after a battery swap, the replacement cell hasn't yet been accepted as a valid backup source. The BGS-220 requires the battery to sit at float voltage for up to 48 hours before the panel treats it as a reliable backup. During that conditioning window, a mains interruption can cause the panel to lose volatile memory. Let the panel run on mains power for 48 hours after fitting the new cell before testing backup behaviour.