Radix City 40 Cordless Phone Replacement Battery 3.6V 1200mAh

Radix City 40 — 3.6V Ni-MH Replacement Battery

This is a 3.6V, 1200mAh Ni-MH battery for the Radix City 40 cordless phone handset. It replaces the original rechargeable pack that powers the handset away from the base station. When the original cell degrades and no longer holds a charge, this pack restores full handset operation.

• City 40 handset fit: The City 40 handset uses a compact Ni-MH cell at 3.6V — the same voltage rail the DECT transmitter and audio circuit run on. Swapping to a different voltage or chemistry causes the base station to misread charge state or refuse to charge altogether.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a cordless phone test rig. The BMS accepted charge normally from a standard base station dock, and the cell voltage held within the expected window across the full discharge curve.
• First charge on a new NiMH handset pack: After installing, seat the handset in the base for a full 16-hour charge before use. NiMH cordless phone cells need that slow first charge to reach rated capacity — cutting it short leaves the pack conditioning below 1200mAh for the first several cycles.

Base station showing no charge or error light after battery swap

A replacement NiMH pack that has been sitting in storage can arrive with a resting voltage well below the base station's acceptance threshold. Some DECT base stations interpret this low incoming voltage as a fault and refuse to begin the charge cycle. The fix is a short pre-charge — place the handset in the base, remove it after 30 seconds, then re-seat it firmly. This resets the base station's charge detection and allows the cycle to begin normally from a standing start.

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

NiMH cells do not deliver full rated capacity straight out of the box — this is normal, not a fault. The 1200mAh rating is reached after three to five full charge and discharge cycles, which conditions the cell chemistry. For the first few uses, expect noticeably shorter talk time than the original worn-in pack. Run the handset until the low-battery alert triggers, return it to the base for a full charge, and repeat — by cycle five, the cell should be delivering close to the rated 1200mAh.