How to Replace the Battery on a Sony WF-1000XM4 (Update)

With all the issues of battery drain and the new 1.6.1 firmware possibly decreasing battery life, here is a guide how to replace the battery in your WF-1000XM4. The video can be found here for those interested, I will also embed it at the end. Thanks to Yen Albert for the great video.

As with any home repair, replace your battery at your own risk. If Sony has denied you a warranty repair or they are not willing to admit there is an issue with your unit and will not replace your battery, this guide will go step by step helping you replace your batteries.

Step 1

Using a heatgun, I believe Yen said 90 degrees in the comments on the video, warm the earbuds about 7-8 seconds around the seam. This should heat up the adhesive that is on the seam, making it easier to separate the 2 halves. If you do not have a heatgun, you can try using a hairdryer, but be careful.

Step 2

Next, slowly and carefully using a spudger, open up the earbuds. Ideally a plastic one as not to damage the earbuds, but a metal one (like in the video) will be fine. Work the spudger around the entire seam to separate the 2 halves.

Step 3

Be careful when separating the 2 halves since there is a ribbon cable (1) connecting the 2 pieces, and there is a board to board PCB (2) connected to one side as well. You do not want to rip this cable.

Step 4

Using a spudger again, slowly lift the small PCB which is attached to the other side. This contains the board to board connector. Once it is disconnected, separate the 2 halves. 

Step 5

Next, you will need to lift a small latch that anchors the feedback MEMS ribbon cable. Once you have successfully lifted this black piece to the up position (see small close up photo), you can gently remove the ribbon cable from the connector. Plastic tweezers would be the best tool here. Swing the cable out of the way.

Step 6

To separate the battery PCB attached to the negative pole, Yen used a couple of drops of Falcon 530 Electronic contact cleaner between the battery and PCB. You can try to heat up the PCB again with a hair dryer/heatgun or perhaps use some high percentage Isopropyl alchohol, but use a dropper as to minimize the amount used. This should help release the adhesive a bit.

Step 7

Using something thin, wedge it between the battery and PCB and begin to separate the adhesive tape from the battery. Be careful, since on the PCB is the battery contact and you do not want to damage this. So do not use too much force and slowly move down the adhesive tape.

Step 8

The next problem is removing the battery. The main issue is that it is also held down by adhesive at the bottom as well, so heating it up with a hair dryer should help soften the adhesive. After it is warmed up, slowly lift the battery up, use gentle force (see video), but not too much.

Step 9

Replace the battery. 

Yen used a Varta CP1254 A3 which has a lower capacity and voltage than the Zenipower Z55H. There is an Aliexpress listing for a Z55H battery HERE, but I am not sure how legit it is. It looks real in the photos, so if anyone wants to order the batteries, check the link. If you order them, check the delivery date as they could take a while to get delivered. 

UPDATE

I have spoken to the seller on Aliexpress, see link above, and they claim they are the manufacturer of the battery, meaning ZeniPower.

Step 10

Re-attach the PCB with the contact to the battery. Gently press it in place, make sure it stays in place.

Step 11

Next, insert the small ribbon cable from step 5 back into the connector, and close the small black piece down to hold the cable in place. See the small photo to see how far it should go.

Step 12

Reconnect the small PCB with the board to board connector so the 2 halves are now back together. The connectors should just click into each other.

Step 13

Before closing the earbud up, take your case and stick the earbud into it to recharge (great tip from Yen in the video). If the LED lights up, it works and charges correctly. If the LED starts to flash, you did something wrong, check to make sure the battery has full contact and all connections are connected.

Step 14

Finally, you can glue up the seam and close the earbud halves together. Yen used T-9000 Glue, which is clear acrylic adhesive. You can find this on Amazon, but also check for E6000, B6000 or B7000 glues in your local arts and crafts stores. Perhaps some jewelers repair stores will also have this. These glues are special glues that dry clear and are still flexible yet hold solidly well. Be careful when applying the glue, too much will could cause it to squeeze out from the seam.

Please DO NOT use regular superglue

To replace the other side, just repeat the procedure. Anyways, that should be the entire guide, thanks to Yen Albert for a fantastic video. Make sure to check out his video (see below), drop him a like and follow, he has a lot of battery replacement videos of all kind. Leave any questions below here, or better yet, on Yen's video in the comments.

Please share this in post or the video in any forums or threads discussing WF-1000XM4 battery replacement and drain issues.