When they're new, Sony WH-1000XM4 headphones are rated at up to 30 hours with noise cancelling on. If yours now last a few hours, switch off at 20–30%, or are flat every time you pick them up, something has changed.
Sometimes it's a setting or a firmware glitch, and that's free to fix. More often on an XM4 that's a few years old, the battery has simply worn out. That's normal, and a battery replacement brings them back.
Start with the free checks below. If none of them helps, the battery is the likely cause.
Free checks first
1. Update the firmware
Open Sony's headphones app and check for a firmware update. Updates fix bugs, and battery behaviour is one of the things they can change. Keep the headphones charged and close to your phone while it installs.
2. Reset the headphones
A reset clears a lot of odd behaviour, including batteries that report the wrong level. There's a simple restart and a full factory reset. My guide on how to reset Sony WH-1000XM4 shows both.
3. Check what's switched on
Some features use more battery than others. In Sony's app, look at:
- Noise cancelling. It's the biggest user of power. The XM4 lasts noticeably longer with it off.
- LDAC and DSEE Extreme. High-quality Bluetooth and Sony's upscaling both cost battery.
- Speak-to-Chat and Adaptive Sound Control. These keep microphones and sensors working in the background.
- Connecting to two devices at once. Multipoint keeps two Bluetooth links alive.
Try a day with the extras off. If battery life jumps, it's a settings issue, not a worn battery.
4. Check the auto power-off setting
If they're flat every time you pick them up, check the automatic power-off setting in the app. Headphones left on standby, or that switch back on while you're not wearing them, drain overnight. Store them in the case and switch them off fully if you won't use them for a while.
5. Try a different cable and plug
Charge fully with a known-good USB-C cable and plug, and watch the charging light. If they only charge for a minute and stop, or won't take a charge at all, that's a different problem: see Sony headphones not charging.
6. Keep them warm
Lithium batteries hold less in the cold. If they die quickly on cold mornings but are fine indoors, that's normal behaviour rather than a fault.
Signs the battery has worn out
If you've tried the checks above and you're still seeing these, the battery is the likely culprit:
- Short life with all the extras off. A few hours where they used to last days.
- Sudden drops. The level falls from 50% to 20% in minutes, or they switch off with charge supposedly left.
- No improvement after a factory reset and a fresh full charge.
- They've been in daily use for a few years. The XM4 came out in 2020, so many pairs have now been charged hundreds of times.
A lithium battery loses capacity with every charge cycle. Heat, leaving them at 0% for long spells, and keeping them on charge for days on end all speed that up. After a few years of daily use, a big drop in battery life is normal wear, not a fault.
One safety note: if an ear cup looks swollen or bulges, or the headphones get hot while charging, stop charging them and don't use them. A swollen battery needs replacing.
How an XM4 battery is replaced
The battery sits inside one of the ear cups, held in with adhesive and connected to the main board. The repair goes like this:
- I remove the ear pad and the screws, and open the ear cup.
- I disconnect the old battery and ease it off its adhesive without stressing the board or flexing the cells.
- I fit a new battery with fresh adhesive, reconnect it, and close the ear cup.
- I charge it fully and run a discharge check, along with the full bench test: both drivers, noise cancelling, microphones, touch controls and Bluetooth.
There's a step-by-step guide on iFixit if you'd like to do it yourself. The main risks are damaging the battery while prying it out, which you must avoid with lithium cells, and breaking the small connector or the cables around it.
Is a new battery worth it on an XM4?
If the headphones are otherwise in good order, yes. A new battery costs a fraction of a replacement pair and gives the XM4 its full battery life back. If the hinge is also cracking and the pads are flat, add those up before deciding. My guide on whether it's worth repairing Sony headphones goes through the sums.
Questions people ask
How long should a Sony XM4 battery last?
Sony rates it at up to 30 hours with noise cancelling on when new. After a few years of daily use, much less than that is normal.
Can you replace the battery in Sony XM4 headphones?
Yes. It's held in with adhesive inside an ear cup, and can be replaced. See my Sony headphones battery replacement.
Why do my XM4s go flat when I'm not using them?
Usually a setting: standby or auto power-off. Check the app, switch them off fully when you're done, and store them in the case. If they still drain while off, the battery or the board may be at fault.
Is it safe to post headphones with a worn battery?
Yes, as long as the battery is inside the headphones and not swollen. Royal Mail accepts lithium batteries contained in the device. Pack them in their case or a padded box. If the battery looks swollen, contact me before posting.
My recommendation
Do the free checks first: firmware, reset, settings, cable. They take ten minutes and sometimes solve it. If the XM4 still won't last, the battery has worn out, and a new one gives you back the battery life you had.
If you'd like me to fit it, book a Sony headphones battery replacement.