Shure ADX2 Replacement Battery 3.7V 3400mAh Li-ion

Shure ADX2 / ADX2FD Handheld Wireless Transmitter — 3.7V Li-ion Replacement Battery (SB920 / 95A25763)

This is a 3.7V, 3400mAh Li-ion battery for the Shure ADX2 and ADX2/FD handheld wireless microphone transmitters. It replaces OEM part numbers SB920, SB920A, 95A25763, 95A45272, and 95A46272. If your original battery is not holding charge or causing dropouts mid-performance, this is the direct replacement.

• ADX2 and ADX2/FD fit: Both transmitter variants share the same battery bay geometry, connector orientation, and BMS handshake protocol — one cell fits all variants listed under those model numbers without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on an ADX2 transmitter. The BMS held steady voltage delivery through high-RF-output periods and tripped cleanly at low-cell protection threshold without causing a mid-cycle dropout event.
• Transmitter RF power and battery draw: The ADX2 operates at up to 50mW RF output, which pulls harder on the cell than most wireless systems. A degraded or counterfeit cell will show voltage sag under that load before the transmitter's battery indicator registers low — causing audio artifacts before any warning appears.

Why the ADX2 transmitter cuts out mid-performance on a new battery

A new cell that reads full voltage at rest can still sag under the sustained 50mW transmit draw of the ADX2. If the cell's internal resistance is high — common in aged or low-grade replacements — the BMS will trip a low-voltage cutoff during peak RF output bursts even though the indicator showed adequate charge. The result is a sudden dropout with no warning. The fix is ensuring the replacement cell matches the original's discharge curve, not just its rated voltage and capacity.

Receiver losing lock on the ADX2 transmitter after a battery swap

After installing a new cell, some users find the receiver no longer locks onto the transmitter signal. This is not a frequency mismatch — it happens because the transmitter's RF output stage needs a full power cycle to re-initialise its link parameters after the cell is changed. Power the transmitter completely off, wait five seconds, then power it back on. The receiver should reacquire the signal at that point without any channel reassignment needed.