Radio Shack 23-966 Cordless Phone Replacement Battery 3.6V P103

Radio Shack 23-966 / 43-9004 Series — 3.6V Ni-MH Replacement Battery (P103)

This is a 3.6V, 700mAh Ni-MH rechargeable battery for Radio Shack cordless phone handsets. It fits the 23-966, 43-9004, 43-9015, and 43-9016 models, among others. Cross-references include HHR-P103, HHR-P103A, TYPE 25, and OEM part 89-1324-00-00.

• Multi-model fit across the 43-9000 platform: These handsets share the same 3.6V three-cell NiMH pack format, identical connector pinout, and matching physical footprint — 47mm × 32mm × 11.5mm. Swapping between models in this family carries no electrical risk as long as voltage matches.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a 43-series handset. The base station accepted the battery without error, the BMS balanced all three cells correctly, and voltage held steady at 3.6V nominal through the full discharge curve.
• First charge on NiMH handset packs: After installing, seat the handset in the base and leave it there for a full 16 hours before first use. NiMH cells shipped in partial charge state need a slow, uninterrupted first cycle to reach rated capacity — skipping this shortens talk time across all subsequent cycles.

Range dropping after a battery swap on DECT handsets

DECT transmit power draws sharp current bursts — up to several hundred milliamps — each time the handset pings the base. A NiMH pack that hasn't completed its first conditioning cycle has higher internal resistance than a fully formed pack. That resistance causes voltage to sag under RF load, which reduces transmit power and shrinks range. After three to five full charge-discharge cycles, internal resistance drops and range returns to normal.

Base station shows no charge light or error after installing a new pack

NiMH batteries self-discharge during storage and can arrive below the voltage threshold the base station uses to detect a valid pack — typically around 3.0V for a 3-cell NiMH. If the base shows no charging light or flashes an error immediately after install, the pack voltage may be too low for the base to accept a trickle charge. Place the handset firmly in the base, wait 10 minutes, then remove and reseat it. If the error clears, the base has accepted the pack and charging has started — check for a steady charge indicator at 3.6V after 16 hours.