Alcatel-Lucent 3MG08009AA Cordless Phone Replacement Battery 3.7V 320mAh

Alcatel-Lucent 3MG08009AA / Wide Band 4.1 Bluetooth — 3.7V Li-Polymer Replacement Battery (GSP04253501A)

This 3.7V 320mAh Li-Polymer battery replaces the GSP04253501A in the Alcatel-Lucent 3MG08009AA and Wide Band 4.1 Bluetooth cordless handsets. At 37.00 x 25.00 x 4.60mm, it fits the original battery compartment without modification. Capacity matches the OEM spec at 320mAh (1.18Wh).

• 3MG08009AA and Wide Band 4.1 platform: Both handsets share the same 3.7V single-cell Li-Polymer rail, connector pinout, and BMS handshake — one battery covers both. The BMS monitors cell voltage directly; no firmware pairing is required between battery and base station.
• Bench tested on actual hardware: We ran charge and discharge cycles on this cell and confirmed BMS cutoff at the correct low-voltage threshold. The protection circuit tripped cleanly at the expected floor, with no false overcharge flags during the charge phase.
• First-cycle charging on Li-Polymer cordless handsets: After installing this battery, seat the handset in the base and allow a full uninterrupted charge before first use. Li-Polymer cells in low-current cordless chargers can take longer than NiMH equivalents to reach rated capacity on the first cycle — pulling the handset early shortens that first charge.

Talk time shorter than original battery after replacement

A new Li-Polymer cell ships partially discharged for transport safety — typically at 40–60% state of charge. If you use the handset before completing a full charge cycle, available capacity is lower than rated. The BMS also needs one or two full charge-discharge cycles to calibrate its voltage-to-capacity curve accurately. Run two complete cycles — full charge, use until the handset signals low battery, full charge again — before judging talk time.

Handset not pairing or re-registering after battery swap

Some DECT handsets lose their base station registration when power is fully removed during a battery change. The handset stores pairing data in volatile memory on certain Alcatel-Lucent models, and a cold swap clears it. Re-registration is done from the handset menu under Settings → Register Handset, or by holding the Find/Page button on the base for five seconds until the base enters pairing mode. Check your handset manual for the exact sequence — the process takes under two minutes.