About this replacement
Tribit Stormbox / XSound Plus 2 — 7.4V Li-ion Replacement Battery (INR18650-2S1P)
This is a 7.4V 3400mAh (25.16Wh) Li-ion replacement battery for the Tribit Stormbox and XSound Plus 2 Bluetooth speakers. It slots in where the original INR18650-2S1P pack sits, restoring the speaker to full operation without buying a new unit. Match the part number before ordering — voltage and connector orientation must align.
- Stormbox and XSound Plus 2 compatibility: Both speakers share the INR18650-2S1P cell configuration — a 2S1P arrangement running two 18650 cells in series at 7.4V nominal. The amplifier board and charge controller on both models are tuned to this voltage rail, so the BMS handshake and charge cutoff behaviour carry over directly.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on the Stormbox platform, monitoring BMS cutoff response under combined amplifier and Bluetooth radio draw. The protection circuit tripped correctly at low-voltage threshold without false cutoffs during high-volume audio bursts.
- Monthly discharge cycle for desk-use speakers: If this speaker sits on a desk and gets topped off constantly before dropping below 50%, run it down past 20% at least once a month before recharging. Constant shallow cycling causes fuel gauge drift on the charge controller, making the battery indicator read inaccurately before actual capacity loss shows up.
Audio distorting before the battery indicator reaches empty
This happens when the pack voltage sags under the combined current draw of the amplifier and Bluetooth radio at high volume. The amplifier hits its minimum supply voltage before the fuel gauge registers empty, causing clipping distortion rather than a clean shutdown. It is not a speaker fault — it is the battery struggling to deliver enough current at end-of-discharge. A new or well-conditioned pack holds voltage closer to 7.4V under load, keeping the amplifier out of clipping range down to around 6.8V before the BMS steps in.
USB charging not waking up after the speaker sat unused for months
When a Li-ion pack self-discharges below roughly 2.5V per cell (5.0V across the 2S pack), most USB-C charge controllers will not initiate a charge cycle — the voltage is too low for the PD handshake to complete. The BMS on the INR18650-2S1P pack includes a low-voltage recovery path, but it requires a trickle-charge stimulus to wake it. Try a different charger that outputs a steady 5V at 1A or higher and leave it connected for at least 30 minutes before checking for any charge indicator response. If the pack recovers past 6.0V, normal charging resumes.