Sony VGF-WA1 Replacement Battery 11.1V 3350mAh Li-ion

Sony VGF-WA1 — 11.1V Li-ion Replacement Battery (6ZO4A)

This is a 11.1V, 3350mAh Li-ion replacement battery for the Sony VGF-WA1 portable wireless speaker. It replaces OEM part number 6ZO4A. The VGF-WA1 draws power from this cell to run both the amplifier stage and the wireless radio simultaneously.

• VGF-WA1 power rail: The VGF-WA1 runs a combined amplifier and wireless radio load off a single 11.1V cell string. Both loads pull from the same pack, so the BMS must handle combined current spikes when the amplifier pushes high output while the radio is actively transmitting. This battery matches the original connector format and BMS handshake protocol the speaker expects on startup.
• Bench tested on actual hardware: We cycled this battery through repeated combined amp-plus-radio loads on the bench. The BMS held the output rail stable under sudden audio transients without tripping the overcurrent cutoff. Cell voltage returned to within spec after each load spike.
• Monthly discharge cycle for VGF-WA1 users: The VGF-WA1 is often left on a desk and topped off constantly before the pack drops below 50%. Run the speaker down below 20% at least once a month before recharging. Skipping this causes fuel gauge drift, where the speaker reports a full charge but the usable capacity has quietly dropped cycle by cycle.

Why the VGF-WA1 cuts audio before the battery indicator reaches empty

At high volume, the amplifier pulls a surge of current that the cell cannot sustain cleanly. Cell voltage sags below the amplifier's minimum operating threshold before the fuel gauge registers low. The speaker reads remaining capacity in the cell, not instantaneous voltage under load, so the indicator still shows charge when the audio cuts or distorts. Replacing an aged cell with a fresh 3350mAh pack restores the headroom the amplifier needs to handle those transients without clipping.

VGF-WA1 won't wake from USB after sitting unused for weeks

Li-ion cells that self-discharge below roughly 2.5V per cell trip an over-discharge protection latch in the BMS. When the cell string drops that low, the USB charging circuit sees a voltage below the minimum acceptance threshold and refuses to begin a charge cycle. Connect the speaker to a USB source and hold the power button for 10 seconds — this forces a BMS re-initialisation attempt on some firmware revisions. If the pack has sat deeply discharged for more than a few weeks, the cells may not recover and a replacement battery is the correct fix.