Logitech MX Master 3S Battery Replacement

Introduction

Use this guide to replace the battery in your Logitech MX Master 3S mouse.

Lithium-ion batteries have a limited lifespan. If your mouse dies quickly, it may be time to replace the battery.

If possible, follow this guide after your battery has fallen below 25% charge. While your MX Master 3S has a relatively small battery, any charged battery is a potential safety hazard if accidentally bent or punctured.

What you need

Step 1 Soften the mouse feet adhesive

Logitech MX Master 3S Battery Replacement, Soften the mouse feet adhesive: step 1, image 1 of 3

Logitech MX Master 3S Battery Replacement, Soften the mouse feet adhesive: step 1, image 2 of 3

Logitech MX Master 3S Battery Replacement, Soften the mouse feet adhesive: step 1, image 3 of 3

Flip the mouse's power switch into the OFF position, unplug any cables, and flip it over so the feet are facing up.
The unique shape of some mice can prevent them from laying flat. If you need to, lay your mouse on a soft towel to prevent wobble.
If you're planning to reuse your existing mouse feet, note that the adhesive needs to be thoroughly heated for them to be cleanly removed.
Heat an iOpener and apply it to each of the mouse feet for about one minute each.
Alternatively, you can use a hair dryer to soften the mouse feet adhesive.
When using a hair dryer, don't heat the feet for more than a couple seconds at a time—anything hotter than just warm to the touch risks melting or warping the plastic lower case.
The information sticker adhesive may soften during this step, but you don't need to remove it.

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Step 2 Separate the mouse foot adhesive

Logitech MX Master 3S Battery Replacement, Separate the mouse foot adhesive: step 2, image 1 of 3

Logitech MX Master 3S Battery Replacement, Separate the mouse foot adhesive: step 2, image 2 of 3

Logitech MX Master 3S Battery Replacement, Separate the mouse foot adhesive: step 2, image 3 of 3

Slide an opening pick under an edge of the left mouse foot.
Go slowly, and make sure the pick slides underneath both the foot and its adhesive pad. These layers separate easily.
If you plan on reusing your mouse feet, be careful not to crease them or separate them from their adhesive pads.
If the foot feels stuck, apply more heat before continuing.
Slide your pick under the foot to separate its adhesive until you can grab it with your fingers.
Peel up and remove the left mouse foot.

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Step 3 Remove the remaining feet

Logitech MX Master 3S Battery Replacement, Remove the remaining feet: step 3, image 1 of 3

Logitech MX Master 3S Battery Replacement, Remove the remaining feet: step 3, image 2 of 3

Logitech MX Master 3S Battery Replacement, Remove the remaining feet: step 3, image 3 of 3

Repeat the previous two steps for the three remaining feet.
The front foot doesn't cover any screws—if you're only removing the mouse feet to open up the mouse, you don't need to remove this foot.

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Step 4 Reassembly information

Logitech MX Master 3S Battery Replacement, Reassembly information: step 4, image 1 of 3

Logitech MX Master 3S Battery Replacement, Reassembly information: step 4, image 2 of 3

Logitech MX Master 3S Battery Replacement, Reassembly information: step 4, image 3 of 3

If the adhesive separated from the foot:
Slide the flat end of a spudger under an edge of the adhesive. If the adhesive seems stuck, you may need to heat the adhesive further.
Use a pair of tweezers or a spudger to remove any large chunks of leftover adhesive.
For installing new mouse feet or reusing your old ones:
Thoroughly clean the bottom of the mouse with isopropyl alcohol and a lint-free of microfiber cloth. Allow the surface to dry completely.
Peel your new mouse feet away from their adhesive liners and press them firmly into place.

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Step 5 Unfasten the lower case

Logitech MX Master 3S Battery Replacement, Unfasten the lower case: step 5, image 1 of 1

Use a Phillips screwdriver to remove the five 4.3 mm‑long screws securing the bottom half of the lower case.
Use a T5 Torx driver to remove the one 4.2 mm‑long screw securing the top half of the lower case.

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Step 6 Release the left clips

Logitech MX Master 3S Battery Replacement, Release the left clips: step 6, image 1 of 3

Logitech MX Master 3S Battery Replacement, Release the left clips: step 6, image 2 of 3

Logitech MX Master 3S Battery Replacement, Release the left clips: step 6, image 3 of 3

Insert your opening pick into the seam between the thumb rest and the lower case.
Slide your pick right, towards the rear of the upper shell and pry upward to release the left clips.

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Step 7 Release the right clips

Logitech MX Master 3S Battery Replacement, Release the right clips: step 7, image 1 of 2

Logitech MX Master 3S Battery Replacement, Release the right clips: step 7, image 2 of 2

Gently pry the upper shell and lower case apart to release the clips on the right side of the mouse.
Don't try to fully remove the top shell just yet—another clip and a delicate cable connect the upper shell to the lower case.

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Step 8 Release the final clip

Logitech MX Master 3S Battery Replacement, Release the final clip: step 8, image 1 of 3

Logitech MX Master 3S Battery Replacement, Release the final clip: step 8, image 2 of 3

Logitech MX Master 3S Battery Replacement, Release the final clip: step 8, image 3 of 3

Lay your mouse down onto your work surface, making sure none of the clips re-engage.
Grasp the upper shell and partially lift up the right edge.
Pull the upper shell up and back to release the final clip and separate the upper shell from the lower case.
Still keep the two halves close together—a cable is still tethered to the upper shell.
To reinstall the upper shell, slide the front edge into place first, then press down around the perimeter of the upper shell to engage the remaining clips.

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Step 9 Reposition the upper shell

Logitech MX Master 3S Battery Replacement, Reposition the upper shell: step 9, image 1 of 3

Logitech MX Master 3S Battery Replacement, Reposition the upper shell: step 9, image 2 of 3

Logitech MX Master 3S Battery Replacement, Reposition the upper shell: step 9, image 3 of 3

Be careful not to strain the cable connecting the upper shell to the lower case.
Lift the upper shell away from the lower case and lay it to the right of the mouse.

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Step 10 Disconnect the interconnect cable

Logitech MX Master 3S Battery Replacement, Disconnect the interconnect cable: step 10, image 1 of 3

Logitech MX Master 3S Battery Replacement, Disconnect the interconnect cable: step 10, image 2 of 3

Logitech MX Master 3S Battery Replacement, Disconnect the interconnect cable: step 10, image 3 of 3

Use the flat end of a spudger to gently lift up the sliding lock on the interconnect cable socket.
Slide the cable straight out of its socket on the motherboard.
During reassembly, insert the cable into the socket with its blue tab facing out, then push down the sliding lock to secure the cable.

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Step 11 Remove the upper shell

Logitech MX Master 3S Battery Replacement, Remove the upper shell: step 11, image 1 of 1

Remove the upper shell from the lower case.

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Step 12 Disconnect the battery

Logitech MX Master 3S Battery Replacement, Disconnect the battery: step 12, image 1 of 3

Logitech MX Master 3S Battery Replacement, Disconnect the battery: step 12, image 2 of 3

Logitech MX Master 3S Battery Replacement, Disconnect the battery: step 12, image 3 of 3

Use a pair of tweezers to grip the top of the battery connector.
Always pull cables by their connectors and not the wires themselves.
Gently rock the connector side to side and pull it out of its socket.
The connector is held tightly within its socket. If it feels stuck, try a different grip—use the protrusions around the neck of the connector if you need more leverage.
If the connector won't budge, skip to the next step for an alternate method.

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Step 13 Disconnect the battery with tweezers

Logitech MX Master 3S Battery Replacement, Disconnect the battery with tweezers: step 13, image 1 of 3

Logitech MX Master 3S Battery Replacement, Disconnect the battery with tweezers: step 13, image 2 of 3

Logitech MX Master 3S Battery Replacement, Disconnect the battery with tweezers: step 13, image 3 of 3

If your battery connector still feels stuck:
Insert each arm of a pair of pointed tweezers into the cutouts on the side of the battery connector's motherboard socket.
Push the connector up, just enough to grip the top of the connector with another pair of tweezers or your fingers.
Pull the battery connector completely out of its socket to disconnect it.

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Step 14 Unfasten the battery housing

Logitech MX Master 3S Battery Replacement, Unfasten the battery housing: step 14, image 1 of 1

Use a Phillips screwdriver to remove the two 3.5 mm-long screws securing the battery housing.

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Step 15 Remove the battery housing

Logitech MX Master 3S Battery Replacement, Remove the battery housing: step 15, image 1 of 2

Logitech MX Master 3S Battery Replacement, Remove the battery housing: step 15, image 2 of 2

Remove the battery housing from the lower case.

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Step 16 Soften the battery adhesive

Logitech MX Master 3S Battery Replacement, Soften the battery adhesive: step 16, image 1 of 2

Logitech MX Master 3S Battery Replacement, Soften the battery adhesive: step 16, image 2 of 2

The battery is secured within its housing by some light adhesive.
Flip the battery housing over so the battery is facing down.
Apply a heated iOpener to the battery housing for about 2 minutes to soften the battery adhesive.

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Step 17 Separate the battery adhesive

Logitech MX Master 3S Battery Replacement, Separate the battery adhesive: step 17, image 1 of 3

Logitech MX Master 3S Battery Replacement, Separate the battery adhesive: step 17, image 2 of 3

Logitech MX Master 3S Battery Replacement, Separate the battery adhesive: step 17, image 3 of 3

Insert the long edge of an opening pick between the battery and its housing at the side opposite the battery cable.
Push the opening pick under the battery and lift up to pry the battery out of its housing.
Make sure you push underneath the battery and not into it. Don't bend, crease, deform, poke, or puncture the battery—a damaged battery is a potential fire hazard.
If you encounter significant resistance, pause and reheat the adhesive.

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Step 18 Remove the battery

Logitech MX Master 3S Battery Replacement, Remove the battery: step 18, image 1 of 3

Logitech MX Master 3S Battery Replacement, Remove the battery: step 18, image 2 of 3

Logitech MX Master 3S Battery Replacement, Remove the battery: step 18, image 3 of 3

Tool used on this step:

Tesa 61395 Tape

$5.99

Buy

Remove the battery.
To install a new battery:
Use a spudger or your fingers to peel any old adhesive off of the battery housing. The old adhesive shouldn't leave any residue.
If your new battery doesn't come with preinstalled adhesive, place a couple strips of double-sided tape into the battery housing.
Orient your new battery so its cables route through the cutout in the corner of the housing. Press the battery firmly into place to secure it.

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Conclusion

Compare your new replacement part to the original part—you may need to transfer remaining components or remove adhesive backings from the new part before you install it.

To reassemble your device, follow these instructions in reverse order.

For optimal performance, calibrate your newly installed battery after completing this guide.

Take your e-waste to an R2 or e-Stewards certified recycler.

Repair didn’t go as planned? Try some basic troubleshooting, or ask our Answers community for help.

One other person completed this guide.