Braven 600 Replacement Battery 3.7V 1400mAh Li-Polymer

Braven 600 — 3.7V Li-Polymer Replacement Battery (PS403648T)

This 3.7V, 1400mAh Li-Polymer cell replaces the original PS403648T battery in the Braven 600 portable Bluetooth speaker. It restores audio playback and hands-free calling capacity lost to cycle-worn cells. Voltage and capacity match the stock specification exactly.

• Braven 600 fitment: The Braven 600 uses a single flat Li-Polymer cell at 3.7V nominal. The BMS inside the speaker monitors cell voltage directly — any deviation in nominal voltage or connector polarity triggers charge refusal. This cell matches both parameters, so the onboard BMS accepts it without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Braven 600 platform. The BMS completed a full charge cycle without flagging an error, and the fuel gauge tracked cell voltage accurately across the full discharge curve.
• Monthly discharge cycle for the Braven 600: Let the speaker drain below 20% at least once a month before recharging. The Braven 600 is typically left on a desk and topped off constantly — this shallow cycling causes fuel gauge drift over time, making the battery indicator unreliable well before the cell reaches end of life.

Why the Braven 600 reports full charge but audio cuts after extended play

A Li-Polymer cell that has been shallow-cycled for months loses the ability to hold voltage under amplifier load, even though it charges to 4.2V without issue. The Braven 600's fuel gauge reads state-of-charge from voltage at rest — not under load. When the amplifier draws current at moderate volume, the degraded cell sags below the BMS cutoff threshold and the speaker shuts down. The fix is a full replacement cell, not a reset — a worn cell cannot recover lost capacity.

Audio distorting before the battery indicator reaches empty

This happens when the cell voltage sags under peak amplifier current demand before the indicator shows low battery. At high volume, the amplifier draws sharp current spikes that drop cell voltage momentarily below the clean-audio threshold. The speaker's circuitry clips the audio signal rather than shut down immediately, producing audible distortion. If distortion clears at lower volume but returns when you turn it up, the cell is the cause — check cell resting voltage with a multimeter; anything below 3.6V at rest confirms replacement is needed.