Swissvoice Iron 3.7V Li-ion Replacement Battery 500mAh

Swissvoice Iron — 3.7V Li-ion Replacement Battery

This is a 3.7V 500mAh Li-ion battery for the Swissvoice Iron cordless phone handset. It slots into the handset to restore power after the original cell has lost the ability to hold charge. Voltage and form factor match the Iron's power circuit directly.

• Swissvoice Iron handset fit: The Iron handset runs a single-cell Li-ion supply rail at 3.7V nominal. This cell matches that rail. The BMS in the handset reads cell voltage on contact — a mismatched voltage causes an immediate rejection or no-charge state.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Li-ion test rig. The protection circuit cut off correctly at low-voltage threshold and the cell accepted a full charge without thermal event or BMS trip.
• First charge after fitting: Li-ion cells in storage ship at a partial state of charge. After fitting this battery in the Iron, seat the handset in the base and allow a complete uninterrupted charge before making calls — this lets the BMS calibrate its charge endpoint accurately.

Talk time shorter than expected after fitting a new cell

A new Li-ion cell shipped from storage has not been through a full charge-discharge cycle. The BMS has no accurate baseline for the cell's capacity yet. For the first two to three cycles, the handset may cut out earlier than the rated capacity suggests. By the third full cycle, the BMS recalibrates and talk time reaches the cell's actual rated output.

Swissvoice Iron handset not pairing after battery replacement

Removing the original battery cuts all power to the handset, including the volatile memory that stores the DECT pairing key. Some Iron handsets lose their base station pairing when power is fully interrupted. To restore it, hold the handset's page or find button for five seconds near the base, then press the registration button on the base station. The handset will re-register and resume normal operation.