Swisstone BX200 Replacement Battery 3.7V 1200mAh Li-ion

Swisstone BX200 — 3.7V Li-ion Replacement Battery (HY433450R)

This is the HY433450R Li-ion cell for the Swisstone BX200 portable Bluetooth speaker. It runs at 3.7V with a 1200mAh (4.44Wh) capacity. Fit the BX200 only — confirm the part number on your existing cell before ordering.

• BX200 fit: The BX200 uses a single-cell 3.7V Li-ion pack with a compact 53.10 x 34.20 x 6.50mm footprint. The HY433450R matches that cell geometry, voltage rail, and connector orientation so the BMS handshake clears on first boot.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a BX200 unit. The BMS accepted the pack without error flags, audio output held steady through the charge curve, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• Monthly discharge cycle for the BX200: The BX200 spends most of its life plugged in or topped off between short sessions. Let the battery run below 20% at least once a month before recharging — constant shallow top-off without a full discharge causes fuel gauge drift, and the charge indicator becomes unreliable faster than the cell itself degrades.

Audio distortion before the BX200 battery indicator reaches empty

As the cell discharges toward its lower voltage threshold, the amplifier inside the BX200 loses the headroom it needs to reproduce audio cleanly. The result is clipping — a harsh, crackling distortion — while the LED indicator still shows charge remaining. This happens because the fuel gauge is reading a voltage curve, not actual remaining capacity, and an aged or drifted cell sags faster under amplifier load than the indicator predicts. A fresh HY433450R cell with a consistent voltage curve eliminates most of this sag. If distortion still appears early after fitting a new cell, run two full discharge-recharge cycles to let the BMS recalibrate its gauge.

BX200 not waking from USB charge after sitting unused for weeks

A deeply discharged Li-ion cell can drop below the minimum acceptance voltage that USB charging circuits expect — typically around 2.5V — and the charger simply sees no valid pack to negotiate with. The BX200 will appear completely dead even with a cable connected. Try a different USB power source rated at 5V/1A or higher, and hold the charge cable in place for 10–15 minutes before pressing the power button — some BMS circuits need a slow trickle before they accept a full charge handshake. If the cell has been stored discharged for more than three months, it may be below recoverable voltage and the cell itself needs replacing.