JBL Go 4 Replacement Battery AHB693140 3.7V 850mAh

JBL Go 4 — 3.7V Li-Polymer Replacement Battery (AHB693140)

This is a 3.7V, 850mAh (3.15Wh) Li-Polymer replacement battery for the JBL Go 4 portable Bluetooth speaker. It matches the OEM part number AHB693140 and fits the compact cell cavity inside the Go 4 enclosure. Replace this when the original cell no longer holds a useful charge or fails to accept a charge at all.

• Go 4 cell format: The Go 4 uses a slim Li-Polymer pouch cell measuring 45.20 × 30.00 × 6.90mm. That specific footprint fits the internal cavity without pressure on the flex PCB or speaker membrane frame. The BMS on the Go 4 mainboard expects a 3.7V nominal cell — mismatched voltage trips the protection circuit at first charge.
• Bench tested on actual hardware: We cycled this cell through the Go 4's charge controller and confirmed the BMS accepted the pack without fault flags. Discharge curves held stable through the amplifier's idle and active draw states, with the protection circuit cutting correctly at the low-voltage threshold.
• Monthly discharge cycle for Go 4: If the Go 4 sits on a desk and gets topped off constantly, run it down below 20% at least once a month before recharging. Constant partial-charge cycles cause fuel gauge drift on the Go 4's onboard cell monitor, making the charge indicator unreliable within a few months.

Audio distorting before the battery indicator reaches empty

The Go 4's amplifier needs a stable voltage rail to drive clean audio. As the cell ages and internal resistance rises, voltage sags under amplifier load even when the fuel gauge still reads 20–30%. The amp clips under that sag, producing distortion at moderate to high volume before the low-battery LED ever triggers. Replacing the cell restores a low-resistance source and brings the voltage rail back above the amplifier's clipping threshold — typically around 3.4V under load.

Go 4 not waking from USB-C when deeply discharged

If the Go 4 sits unused for weeks, the cell can drop below the USB-C PD minimum acceptance voltage — usually under 2.5V. At that point the charge controller ignores the USB-C connection entirely and the speaker shows no response. The fix is to apply a trickle charge using the original cable and a 5V 1A source for 15–20 minutes before trying a normal charge cycle. If the cell recovers past 2.8V, the BMS re-initialises and charging resumes normally — if it does not, the cell is below recoverable voltage and needs replacement.