Phonak inspiro 3.7V Compatible Battery 3PINSBR 500mAh

Phonak Inspiro — 3.7V Li-Polymer Replacement Battery (3PINSBR)

This is a 3.7V, 500mAh Li-Polymer replacement battery for the Phonak Inspiro and Inspiro TX hearing device transmitter. It fits the Inspiro, Phonak Inspiro TX, and Roger Inspiro series. Direct swap for OEM part number 3PINSBR.

• Inspiro and Roger Inspiro compatibility: The Inspiro TX and Roger Inspiro share the same battery bay dimensions, voltage rail, and BMS communication protocol — that is why one cell covers the full transmitter range. The 3PINSBR connector and PCM pinout are matched to these units exactly.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Inspiro platform. The BMS accepted the cell without fault codes, and protection circuitry responded correctly to both low-voltage cutoff and overcharge thresholds.
• Inspiro TX microphone sensitivity after swap: If the transmitter has sat discharged for an extended period, allow a full first charge cycle before use. A partially recovered cell can cause the TX unit to flag low-power warnings even when the charge indicator reads full.

Why the Inspiro TX drops audio mid-session at moderate battery levels

The Inspiro TX transmits Roger wireless audio at a fixed RF output level. When the cell ages, internal resistance rises — voltage sags under the RF transmission load even if the charge indicator still shows green. The BMS reads the voltage dip as a low-battery event and throttles or cuts output to protect the cell. A fresh 3.7V cell with low internal resistance holds voltage stable under load, which keeps the RF stage running without interruption.

Inspiro showing "battery full" but cutting out after short use

This happens when a deeply discharged Li-Polymer cell recovers enough voltage to fool the charge indicator but has not completed a full charge cycle. The gauge reads surface charge, not true capacity. Plug the Inspiro into the charger and leave it for a complete uninterrupted charge cycle — do not disconnect early. After one full cycle, check that resting voltage sits at or above 4.1V before use.