Panasonic KX-PRA10 Cordless Phone Replacement Battery 3.7V 1750mAh

Panasonic KX-PRX110 / KX-PRX120 Series — 3.7V Li-ion Replacement Battery (KX-PRA10)

This is a 3.7V, 1750mAh Li-ion battery for the Panasonic KX-PRX110, KX-PRX110GW, KX-PRX120, and KX-PRX120GW cordless DECT handsets. It replaces OEM part number KX-PRA10 — the slim 64.04 × 44.07 × 5.16mm cell that sits behind the handset back panel. Fit is direct; the connector and BMS pinout match the original.

• KX-PRX110 and KX-PRX120 compatibility: Both handset variants run the same 3.7V Li-ion cell with identical connector orientation and BMS communication protocol. Swapping between GW and standard variants requires no modification — the battery management handshake is consistent across the range.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the KX-PRX110 platform. The BMS accepted charge from the base station without triggering a fault state, and voltage held steady at 3.7V nominal through the discharge curve with no mid-cycle cutoff.
• First-charge protocol for this handset: After fitting the new battery, seat the handset in its base and leave it on charge for a full 16 hours before first use. The KX-PRX series base station uses a trickle-charge finishing stage that Li-ion cells require time to complete — cutting this short leaves measurable capacity on the table from the first session.

Talk time shorter than expected after fitting a new battery

A new Li-ion cell ships at partial charge — typically 40–60% — to slow self-discharge during storage. The KX-PRX handset's fuel gauge calibrates itself over the first two or three full charge-discharge cycles. Until that calibration settles, the handset may underreport remaining capacity and shut down earlier than the rated 1750mAh suggests it should. Run two full cycles from base charge to low-battery alert, then recharge fully. Talk time figures stabilise after that.

Handset loses DECT pairing after battery replacement

Removing the battery from a KX-PRX handset cuts all power to the DECT module, including the volatile memory that stores base station registration data. Some units retain the pairing; others drop it entirely — it depends on whether a small supercapacitor on the board holds charge long enough during the swap. If the handset shows "searching" or fails to find the base after reassembly, re-register it from the base station menu using the handset locator button held for three seconds.