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Sony ST-02 SRS-X11 Compatible Battery 7.4V 1000mAh

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From $26.99 USD $33.99
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Fits Sony SRS-X11 portable speaker, replaces OEM ST-02 battery directly.
7.4V, 1000mAh Li-Polymer cell powers wireless audio without the USB cable tether.
Connector seats flush into the speaker's internal slot with single locking tab retention.
We bench-tested the BMS on Sony's charging platform — cell accepts charge at full rate without thermal throttle.
On first use, let the speaker discharge naturally to 15% before the initial full recharge to calibrate the fuel gauge circuit.
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

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Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

7.4V

Amp

1000mAh

Sony SRS-X11 — 7.4V Li-Polymer Replacement Battery (ST-02)

This is a 7.4V, 1000mAh Li-Polymer replacement for the ST-02 battery inside the Sony SRS-X11 portable Bluetooth speaker. It fits the compact SRS-X11 unit and restores wireless playback when the original cell has degraded. Voltage and capacity match the original pack exactly — 7.4V at 7.4Wh.

  • SRS-X11 fitment: The SRS-X11 runs its Bluetooth radio and Class D amplifier from a single 7.4V Li-Polymer cell. The ST-02 form factor — 51.65 × 34.20 × 11.20mm — is specific to this housing. No other Sony SRS cell fits the cavity or meets the voltage rail the amplifier board expects.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on the SRS-X11 board. The BMS accepted charge from the speaker's internal charging circuit without error flags, and discharge cutoff triggered cleanly before cell voltage sagged below the amplifier's minimum operating threshold.
  • Monthly discharge cycle for the SRS-X11: If you keep this speaker on a desk and top it off before it drops below 50%, do a full discharge to under 20% at least once a month before recharging. The SRS-X11's fuel gauge drifts under constant shallow cycling, causing the indicator to read full while actual capacity has already dropped.

Why the SRS-X11 amplifier clips before the battery indicator hits empty

The SRS-X11 Class D amplifier starts clipping audio at high volume when cell voltage sags — even if the battery indicator still shows one or two bars. A degraded Li-Polymer cell has higher internal resistance, so under the combined load of the amplifier and Bluetooth radio, terminal voltage drops faster than the fuel gauge tracks. The indicator reads state-of-charge from a coulomb counter, not live voltage, so the two fall out of sync. Swapping to a fresh cell with lower internal resistance keeps terminal voltage above the amplifier's clipping threshold longer into the discharge cycle.

SRS-X11 not charging after sitting unused for several months

Li-Polymer cells left discharged for extended periods can drop below the minimum acceptance voltage the SRS-X11's charging circuit will recognise — typically under 3.0V per cell, or 6.0V for the 7.4V pack. When this happens, the speaker shows no charging indicator and the LED may blink an error pattern. If the original battery is in this state, it cannot be safely recovered and replacement is the correct path. Plug the new ST-02 in and verify the charging LED goes solid or begins its normal charge cycle within 30 seconds of connecting USB power.

Compatible Models

SRS-X11

Replaces Part Numbers

ST-02

Technical Specifications

Voltage7.4V
Amp Hours1000mAh
Capacity1000mAh
Rate7.4Wh
Net Weight38g /1.34 oz
Gross Weight63g /2.22 oz
Approximate Weight63g /2.22 oz
Dimension 51.65 x 34.20 x 11.20mm

Product Highlights

  • Brand: Sony
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-Polymer
  • Battery Type: Li-Polymer
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My SRS-X11 shows a full charge but the audio cuts out or gets quieter after about an hour of use — is the battery failing?

Yes, this is a fuel gauge drift symptom caused by shallow cycling. When the speaker is topped off constantly without a full discharge, the coulomb counter loses calibration and reads higher than the actual charge remaining. The battery is delivering less capacity than the indicator suggests. Run the speaker down below 20% once, then charge it fully — if the problem persists with the original battery, the cell has degraded and the ST-02 replacement is the fix.

Bluetooth keeps dropping at high volume on my SRS-X11 even though the battery looks charged — what's causing this?

High volume creates a current spike from both the amplifier and the Bluetooth radio simultaneously. On a degraded Li-Polymer cell, internal resistance has risen enough that this combined draw causes a brief voltage sag at the cell terminals. The Bluetooth radio loses enough voltage to drop its connection, even though the fuel gauge still reads mid-charge. A fresh cell with lower internal resistance handles the combined amp-plus-radio draw without the sag — replace the ST-02 and test at maximum volume.

The SRS-X11 feels noticeably warm on the bottom during long listening sessions — is that a battery issue or normal?

Some warmth is normal, but heat from two sources stacks inside the compact SRS-X11 housing: the Class D amplifier generates heat at high output, and the Li-Polymer cell generates heat as it discharges under load. A degraded cell with elevated internal resistance generates more heat than a fresh one under the same current draw. If the bottom of the speaker is hot enough to be uncomfortable to hold, check that the speaker is not resting on a surface that blocks airflow and replace the ST-02 if the battery is more than two years old.

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