Phone Mate 1120 Cordless Phone Replacement Battery 4.8V 1300mAh

Phone Mate 1120 / 1121 / 1140 — 4.8V Ni-MH Replacement Battery

This is a 4.8V, 1300mAh Ni-MH battery pack for the Phone Mate 1120, 1121, and 1140 cordless handsets. It replaces the original rechargeable pack that powers the handset during cordless operation. Dimensions are 56.50 x 50.38 x 14.56mm — measure your existing pack before ordering if you are unsure.

• 1120 / 1121 / 1140 compatibility: These three models share the same 4.8V four-cell NiMH pack and connector footprint. The base charging circuit operates at the same trickle rate across the series, so one replacement covers all three handsets.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a NiMH-compatible analyser. The BMS held voltage within spec across all four cells, and the pack accepted a full trickle charge without thermal event.
• First-charge protocol for NiMH cordless packs: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells in cordless handsets do not reach rated capacity on a short initial charge — skipping this step will leave you with noticeably reduced talk time from day one.

Base station showing no charge light after installing a new NiMH pack

NiMH packs can sit in a warehouse long enough for cell voltage to drop below the threshold the base charging circuit expects. Some Phone Mate bases will not initiate a charge cycle if the incoming voltage reads too low — the charge indicator simply stays off. Place the handset in the base for 30 minutes anyway. Many bases will eventually detect the pack once surface voltage ticks up slightly. If the light remains off, check that the handset contacts are clean and fully seated — even a 1mm gap interrupts the circuit.

Talk time shorter than the original battery after the first few charges

This is normal NiMH behaviour and not a fault with the replacement pack. NiMH cells require three to five full charge-discharge cycles before they deliver rated capacity. Each cycle, the cells reform and capacity steps up. Run the handset until you hear the low-battery warning, then return it to the base for a full charge — repeat this three times. By cycle four, talk time should be consistent with the 1300mAh rating.