Marshall Emberton 3 Replacement Battery 7.4V 2600mAh B0797

Marshall Emberton 3 — 7.4V Li-ion Replacement Battery (B0797)

This is a 7.4V, 2600mAh Li-ion battery for the Marshall Emberton 3 portable Bluetooth speaker. It replaces OEM part B0797, which powers audio playback and wireless connectivity in the Emberton 3 and Emberton III. Swap it in when the original cell no longer holds a charge or capacity has dropped noticeably.

• Emberton 3 and Emberton III compatibility: Both the Emberton 3 and Emberton III share the same battery bay geometry, connector pinout, and BMS handshake protocol — the B0797 cell fits both without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Emberton 3 platform. The BMS accepted the pack without error flags, voltage held steady under combined amplifier and Bluetooth radio draw, and the fuel gauge reported accurately across the full state-of-charge range.
• Monthly discharge cycle for Emberton 3 users: Let the speaker run down below 20% at least once a month before recharging. The Emberton 3 is often kept on a desk and topped off constantly — cycling without a full discharge causes fuel gauge drift, so the indicator reads full while actual capacity has quietly dropped.

Why the Emberton 3 audio drops at high volume even on a fresh charge

At maximum volume the amplifier and Bluetooth radio draw current simultaneously, creating short but sharp load spikes. If the cell's internal resistance has risen — either from age or shallow cycling — voltage sags under that combined draw. The BMS interprets the sag as a low-cell condition and throttles output to protect the cell. Installing a cell with lower internal resistance restores stable voltage delivery under high combined load.

Emberton 3 won't wake from USB-C when the battery is fully flat

When the cell discharges below roughly 2.5V per cell, the BMS enters deep-protection mode and disconnects the output rail entirely. In this state the speaker will not respond to a USB-C cable because the charger cannot negotiate PD handshake without a minimum voltage present at the port. Plug the cable in and leave it connected for 10–15 minutes without pressing any button — the BMS needs that window to trickle enough charge back into the cell to exit protection mode and re-enable the USB negotiation circuit.