Logitech UE Boombox DGYF001 Replacement Battery 3.7V 2800mAh

Logitech UE Boombox — 3.7V Li-ion Replacement Battery (DGYF001)

This is a 3.7V, 2800mAh Li-ion cell that replaces the original battery in the Logitech UE Boombox portable Bluetooth speaker. It fits the UE Boombox (984-000304) and uses OEM part numbers DGYF001, GPRLO18SY002, and 533-000096. Swap it when the original cell no longer holds enough charge to keep the speaker running away from a power source.

• UE Boombox (984-000304) fitment: The UE Boombox uses a single Li-ion cell at 3.7V to power both the amplifier board and the Bluetooth radio. This cell matches the original connector pinout and physical dimensions (65.92 × 21.70 × 19.65mm), so the BMS handshake between the cell and the speaker's charge controller runs without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the UE Boombox platform. The BMS accepted charge from the factory charger without fault, and the protection circuit tripped correctly at low-voltage threshold before the cell reached unsafe depth of discharge.
• Shallow-cycle management on the UE Boombox: Because this speaker often sits on a desk and gets topped off constantly, let the cell drain below 20% at least once a month before recharging. Continuous partial charging without a full discharge cycle causes fuel gauge drift, making the indicator read full when actual capacity has already dropped.

Why the UE Boombox cuts out at high volume even on a fresh charge

At high volume, the amplifier and Bluetooth radio draw current simultaneously, creating a combined spike the cell must deliver instantly. If the cell's internal resistance has climbed — either from age or deep-discharge damage — voltage sags under that peak load and the BMS interprets it as a critically low cell. The speaker cuts audio to protect the circuit before the fuel gauge shows empty. A new cell with lower internal resistance handles the combined amp-plus-radio draw without triggering that cutoff.

Audio distorts before the battery indicator reaches empty

When a degraded cell can no longer hold voltage steady under amplifier load, output voltage sags into the range where the amp clips — this shows up as distortion before the indicator reaches the low-battery warning. The cell still has charge by the gauge's reading, but it cannot deliver clean current at the rate the amplifier demands. This is voltage sag, not a software or speaker fault. Replacing the cell restores stable voltage delivery; confirm the new cell reads above 3.6V under load during initial charge to verify the BMS is tracking correctly.