About this replacement
Shure SHA900 — 3.7V Li-ion Replacement Battery (95A21764)
This is a 3.7V, 1800mAh lithium-ion replacement battery for the Shure SHA900 personal amplifier. It replaces OEM part 95A21764 and fits directly into the SHA900 chassis. Use this when the original cell no longer holds a charge or shuts the amplifier down early.
- SHA900 fit: The SHA900 uses a dedicated single-cell Li-ion pack with a proprietary connector and BMS handshake. This replacement matches that cell configuration, voltage rail, and connector pinout so the amplifier's protection circuit accepts the pack without fault codes.
- Bench tested on actual hardware: We cycled this cell through the SHA900's charge and discharge circuit. The BMS held the low-voltage cutoff correctly and did not false-trip during audio transient peaks at mid-to-high gain settings.
- First-cycle conditioning for audio hardware: Run the SHA900 at 50% volume for the first full charge cycle. Full-volume operation on an uncalibrated cell draws peak current before the BMS has mapped the cell's delivery curve, which can trigger a premature cutoff that sets a lower apparent capacity from cycle one.
Amp shutting off before the battery indicator reaches empty
The SHA900 amplifier requires a minimum supply voltage to sustain its output stage — this threshold sits above the voltage at which the battery indicator registers as empty. When the cell voltage sags under audio load, the amplifier hits its internal cutoff before the fuel gauge does. A worn or partially degraded cell sags further under load, so the gap between the display reading and actual usable voltage widens. Replacing the cell with a fresh 1800mAh pack restores the flat discharge curve that keeps sag within the amplifier's operating window.
Amplifier clipping at moderate volume on a new battery
Clipping on a new battery usually points to an unconditioned cell delivering slightly uneven current during transient audio peaks. The SHA900's output stage clips when the supply rail dips below roughly 3.4V mid-transient. This happens most often in the first few cycles before the BMS has calibrated its charge curve to the cell. Running two or three full charge-discharge cycles at moderate volume typically stabilises the delivery curve and clears the clipping.