The front left view of the Sony SRS XB21 speaker.

Sony SRS XB21 Battery Life

Covers how to check battery life and level on the Sony Extra Bass SRS XB21 Bluetooth speaker, and also, how to know if the battery life is degrading over time.

Sony SRS XB21 Battery Life: Testing the Current Charge

1. First, Turn ON the XB21

You won’t be able to read battery charge status unless the speaker is ON.

The -Power- button on the Sony SRS XB21 speaker.
Sony SRS XB21 -Power- button.

To turn on the speaker, press and release the Power / Pairing button, pointed at by the aqua  arrow in the last picture.

The lamp just above the Power / Pairing button should then light up white, as shown next, and the speaker may make a two-beep ding-dong sound if it pairs to a nearby device.  If it does not turn on, then the battery could be completely dead.

Picture of the glowing -Power- light.
The -Power- lamp glowing.

But as long as there’s some energy in the battery, the speaker should boot up.  When it does, move on to the next step.

2. Have the Speaker Speak Battery Percentage Full

In the ports compartment, there are also a few buttons.  The Light / Batt button is one such button.  The speaker announces the percentage of battery power left as compared to when the battery is fully charged.

Picture of the -BATT- button on the Sony SRS XB21 speaker.
The Sony SRS XB21 speaker -BATT- button.

The announcements made when you tap this button are as follows

    • 70% or greater: The speaker says, “Battery fully charged.”
    • 50% or greater: The speaker says, “Battery about 70%.”
    • 20% or greater: The speaker says, “Battery about 50%.”
    • 10% or greater: The speaker says, “Battery about 20%.”
    • Less than 10%: The speaker says, “Please charge.”

3. Look at the CHARGE Lamp on the XB 21

Or, you can at at least tell at a glance if the battery is on the verge of going dead by way of the CHARGE lamp. When the battery is not too low, this lamp is dark. But when the speaker is running but has very little charge left, this lamp flashes orange. The next picture shows the lamp location.  It’s on the back of the speaker, inside the ports compartment.

Picture of the -CHARGE- light glowing.
The -CHARGE- lamp glowing.

Sony SRS XB21 Battery Life: Testing the Overall Battery Condition

When the speaker is new, and using a USB charger that can supply at least 1.5 amps, the battery charge time is about four (4.0) hours to reach a full charge.

And, the fully charged battery should last for around twelve (12) hours of play time before going dead, when played at low to moderate volume levels with the party lights OFF, and the speaker is neither too hot nor too cold.

A sign of a bad battery, is that it goes dead too quickly, or takes too little or too much time to fully recharge. So if you fully charge your speaker, but it repeatedly only plays for under ten hours before dying, its battery may be bad, and unable to hold a full charge anymore.

If the SRS XB21 battery takes longer than six hours to completely recharge, this could also mean a failing battery.  It might mean as well, that the charger you’re using is not strong enough to recharge the speaker in the specified recharge time.

Also, slow charging can happen because your charge cord is too thin.  So for best results, we recommend a full-current USB cable (one that easily carries at least 2 amps). 

Other Posts About the Sony SRS XB21

    1. How to Connect Sony SRS XB21 to Alexa
    2. Sony XB21 Watts RMS Output, Input, Battery, Adapter
    3. The Sony SRS XB21 BT Speaker and How to Turn it On
    4. How to Pair Sony SRS XB21 BT Speaker to iPhone
    5. How to Check Sony XB21 Battery Capacity

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References for Sony SRS XB21 Battery Life

    1. Sony XB21 SRS Speaker Support Page at

Change History

    • 2022-09-05: First published.