About this replacement
Shure ADX2 Handheld Wireless Microphone Transmitter — 3.7V Li-ion Replacement Battery (SB920)
This 3.7V, 2600mAh (9.62Wh) Li-ion cell is a direct replacement for the rechargeable battery in Shure ADX2 and ADX2/FD handheld wireless microphone transmitters. It uses OEM part numbers 95A25763, 95A45272, 95A46272, SB920, and SB920A. If your transmitter is cutting out mid-show or no longer holding a charge through a full set, this is the cell to replace.
- ADX2 and ADX2/FD compatibility: Both the standard ADX2 and the ADX2/FD share the same battery bay, connector pinout, and BMS handshake protocol — one cell covers both variants without modification.
- Bench tested on actual hardware: We cycled this cell through the SB920A slot on an ADX2 transmitter. The BMS accepted the charge handshake cleanly, and discharge stayed within the transmitter's operating voltage window across the full draw cycle with no protection trips.
- Transmitter storage between gigs: If the ADX2 sits idle for more than two weeks, remove the battery. Shure's transmitter firmware does not cut power draw to zero in standby, and passive drain below 3.0V can push the cell into a state where the BMS refuses the next charge cycle entirely.
Why the ADX2 BMS rejects a charge after deep discharge
Li-ion cells below roughly 2.5V trip the BMS protection circuit into lockout. The ADX2 charger sees this as an absent or faulty cell and stops the charge sequence before current even flows. Many users assume the new battery is dead when the issue is actually the cell sitting too low for a standard charge cycle to initiate. A capable Li-ion charger with a trickle pre-charge mode can recover the cell slowly back above 3.0V, at which point the BMS re-enables the main charge path and normal charging resumes.
Receiver losing RF lock on the ADX2 after a battery swap
When the ADX2 transmitter loses power — even briefly during a battery change — it does not automatically re-establish the RF link with the paired receiver. The receiver holds the last known channel but cannot confirm the transmitter is back online until a full power cycle on the transmitter side. Power the transmitter completely off, wait five seconds, then power it back on. The receiver re-acquires the link within a few seconds once the transmitter's RF output stabilises at operating voltage.