Monster PUCK Replacement Battery 3.7V 1000mAh AHB803040

Monster PUCK / MNPUCK — 3.7V Li-Polymer Replacement Battery (AHB803040)

This 3.7V, 1000mAh Li-Polymer cell replaces part number AHB803040 in the Monster Puck and MNPUCK portable Bluetooth speaker. It fits the compact internal cavity at 43.20 × 29.50 × 8.00mm — check those dimensions against your original before ordering. When the stock cell stops holding a charge, this swap restores full wireless audio playback.

• PUCK and MNPUCK platform fit: Both model designations use the same AHB803040 footprint, voltage rail, and connector. The BMS in these speakers expects a 3.7V nominal cell — substituting a different voltage or a mismatched connector trips the protection circuit and prevents charging.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the PUCK platform. The BMS accepted the cell cleanly, protection thresholds engaged at expected cutoff voltages, and audio output held steady across the draw range without BMS interruption.
• Monthly discharge cycle for the PUCK: The PUCK typically sits on a desk and gets topped off constantly. Let the cell drain below 20% at least once a month before recharging — repeated shallow charging without a full discharge cycle causes fuel gauge drift, and the speaker will report a false "full" reading while actual capacity shrinks.

Why the PUCK cuts audio abruptly at high volume on a new battery

At high volume, the amplifier draws a sharp current spike that combines with the Bluetooth radio draw. On a 1000mAh Li-Polymer cell, that combined load can pull the cell voltage below the BMS low-voltage threshold momentarily. The protection circuit interprets this as a depleted cell and cuts output. If this happens on a new battery, confirm the cell is fully charged to 4.2V before testing — a partially charged cell has less headroom to absorb the amplifier spike without tripping the cutoff.

USB charging not starting after the PUCK sat unused for weeks

Li-Polymer cells self-discharge during storage. If the PUCK sat unused long enough, the cell may drop below the USB charging controller's minimum acceptance voltage. The charger handshake fails and nothing happens when you plug in. Connect the speaker to a USB port and leave it for 15–20 minutes without expecting an indicator light — the internal charger IC uses a trickle pre-charge stage to recover cells in this range. If the cell recovers past roughly 3.0V, normal charging resumes automatically.