JBL Charge Essential 2 Replacement Battery 3.6V 7800mAh

JBL Charge Essential 2 — 3.6V Li-ion Replacement Battery (GSP-1S3P-CH40)

This is a 3.6V 7800mAh Li-ion replacement battery for the JBL Charge Essential 2 portable Bluetooth speaker. It replaces OEM part GSP-1S3P-CH40 and restores both audio playback and the speaker's built-in power bank function. Fit the correct cell and the speaker charges other devices and plays audio again as expected.

• Charge Essential 2 cell format: The GSP-1S3P-CH40 is a single-voltage 3.6V pack wired directly to the speaker's main board. The BMS handles both USB-C charge input and power bank output, so the replacement cell must match the OEM voltage rail — any deviation trips the protection circuit before the speaker powers on.
• Bench tested on actual hardware: We ran the replacement cell through charge, discharge, and USB power bank cycles on the Charge Essential 2. The BMS accepted charge input, cleared the protection latch correctly, and power bank output held stable across the full discharge curve.
• Monthly discharge cycle for the Charge Essential 2: This speaker is used on desks and countertops and rarely gets below 50% before being topped off. Let the cell drop below 20% at least once a month before recharging — constant shallow cycling causes fuel gauge drift, so the battery indicator reads full while actual capacity has quietly dropped.

Why the Charge Essential 2 shows full charge but audio drops after an hour

A degraded Li-ion cell loses usable capacity before the fuel gauge reflects it. The indicator reads full because the BMS calibrates to the cell's current state, not its original 7800mAh rating. As internal resistance climbs with age, the cell voltage sags under the combined draw of the amplifier and Bluetooth radio — the speaker cuts out well before the indicator reaches empty. Replacing the cell resets this mismatch and restores the full discharge window.

USB-C won't wake the speaker after it's been sitting discharged for weeks

When the Charge Essential 2 sits unused for an extended period, the cell can drop below the USB-C PD minimum acceptance voltage — typically around 2.5V per cell — and the BMS locks out charge input to prevent damage. Plugging in a standard USB-C charger at that point produces no response: no LED, no charge current. Use a charger that supports low-voltage recovery or trickle pre-charge mode, hold the connection for at least 10–15 minutes, and the BMS should clear the latch once the cell recovers above 3.0V.