Braven BRV-1S Replacement Battery 3.7V 2000mAh Li-Polymer

Braven BRV-1S Ultra Rugged — 3.7V Li-Polymer Replacement Battery (PT704060)

This 3.7V, 2000mAh Li-Polymer cell replaces the original battery in the Braven BRV-1S and BRV-1S Ultra Rugged portable Bluetooth speakers. It restores wireless audio playback when the factory cell no longer holds a usable charge. The flat pouch format matches the original 60.12 x 40.00 x 6.40mm envelope inside the speaker chassis.

• BRV-1S and BRV-1S Ultra Rugged fitment: Both models share the same internal battery bay dimensions, connector pinout, and fuel gauge circuit. One cell covers both variants without modification.
• Bench tested on actual hardware: We cycled the PT704060 cell through charge and discharge on the BRV-1S platform. The protection circuit handled over-charge cutoff at 4.2V and low-voltage cutoff cleanly, with no false shutdowns during sustained playback draw.
• Monthly discharge cycle on desk-use speakers: If this speaker sits on a desk and gets topped off constantly, run it down below 20% at least once a month before recharging. Constant shallow cycling without a full discharge causes fuel gauge drift, and the speaker will report incorrect charge levels sooner than it should.

Audio distorting before the battery indicator reaches empty

When the cell voltage sags under combined amplifier and Bluetooth radio draw, the amplifier hits its minimum supply voltage before the fuel gauge reads zero. At that point the amp clips the audio signal — you hear crackling or distortion — while the LED still shows one or two bars. This is a voltage sag symptom, not a speaker fault. A fresh cell with lower internal resistance holds the rail steady under that combined load. If distortion starts early on the new battery, check that the cell connector is fully seated, as a loose contact adds resistance that accelerates sag.

Speaker not waking from USB charge after sitting unused for months

A deeply discharged Li-Polymer cell can drop below the minimum voltage a USB charger will accept — typically around 2.5V to 2.7V for this cell chemistry. When that happens, the charger handshake fails and the speaker shows no charging indication at all. Connecting to a USB port and leaving it for 15–30 minutes sometimes allows the protection circuit to recover enough voltage for a normal charge cycle to begin. If the cell has been sitting discharged for several months, recovery is unlikely and replacement is the correct fix.