Radio Shack HHR-P102 Cordless Phone Replacement Battery 3.6V 700mAh

Radio Shack 23-961 / 43-3529 / 43-3553 — 3.6V Ni-MH Replacement Battery (HHR-P102)

This is a 3.6V, 700mAh Ni-MH replacement battery for Radio Shack cordless phone handsets. It fits the 23-961, 43-3529, 43-3538, and 43-3553 models, among others. Physical dimensions are 44.76 × 30.98 × 10.61mm — match these against your original pack before ordering.

• Multi-model fit explained: These Radio Shack handsets share the same 3.6V three-cell NiMH form factor and connector pinout. The base station charges via the same contact rail across all listed models, so one cell configuration covers the range.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a cordless phone bench rig. The BMS held stable at 3.6V nominal, and the pack accepted a full trickle charge from the base cradle without triggering a fault state.
• First-charge protocol for NiMH cordless packs: Place the handset in the base immediately after installing this battery and leave it for a full 16 hours before use. NiMH cells in cordless phones require a slow initial charge to activate all cells evenly — skipping this shortens the effective capacity you get from the first several cycles.

Why the base station shows a charging error on a brand-new NiMH pack

NiMH batteries self-discharge during storage and shipping. If the pack voltage drops low enough, the base station's charge controller reads it as a fault rather than a depleted cell. Radio Shack base units typically expect the pack to present above roughly 3.0V before initiating a normal charge cycle. If the error light stays on, remove the handset, wait 30 seconds, and re-seat it firmly — this resets the charge controller and usually clears the fault so charging begins normally.

Talk time shorter than expected for the first few cycles

NiMH cells do not deliver full rated capacity straight out of the box. The 700mAh rating is achieved after three to five full charge-discharge cycles. Each cycle allows the cell chemistry to stabilise and reach its rated voltage plateau. Run the handset until it signals low battery, then return it to the base for a full charge — repeat this three times and talk time will increase noticeably toward the rated capacity.