Wireless Mouse Power-Up: Logitech MX Master Gets USB-C And Big Battery

When the internal rechargeable battery in his wireless mouse died, [cmot17] decided it was the perfect excuse for making a couple of modifications. The Logitech MX Master isn’t exactly a budget mouse to begin with, but that doesn’t mean there’s no room for improvement. With the addition of a larger battery and USB-C charging port, a very nice mouse just got even better.

As it turns out, there’s plenty of empty space inside the Logitech MX Master, which made it easy to add a larger battery. The original 500 mAh pack was replaced with a new 950 mAh one, which is often sold under the model number 603443. Realistically, if you wanted to go even bigger it looks like any three wire 3.7 V Li-Po pack would probably work in this application, but nearly doubling the capacity is already a pretty serious bump.

Adding the USB-C connector ended up being quite a bit trickier. [cmot17] ordered a breakout board from Adafruit that was just a little too large to fit inside the mouse. In the end, not only did some of the case need to get cut away internally, but the breakout PCB itself got a considerable trimming. Once it was shoehorned in there, a healthy dose of hot glue was used to make sure nothing shifts around.

Since [cmot17] didn’t change the mouse’s original electronics, the newly upgraded Logitech MX Master won’t actually benefit from the faster charging offered by USB-C. If anything, it’s actually going to charge slower thanks to the beefier battery. But considering how infrequently it will need to be charged with the upgraded capacity (Logitech advertised 40 days with the original 500 mAh battery), we don’t think it will be a problem.

Over the years, we’ve seen plenty of stuff crammed into the lowly mouse. Everything from a full computer, to malicious firmware code has been grafted onto that most ubiquitous of computer peripherals. So in the grand scheme of things, this is perhaps one of the most practical mouse modifications to ever grace these pages.

20 thoughts on “Wireless Mouse Power-Up: Logitech MX Master Gets USB-C And Big Battery

  1. Hmmmm, that battery swap looks tasty.
    I have one of these and after over a year of use it certainly doesn’t last the advertised time between charges anymore.
    If only there was a replacement for the rubber on the scroll wheel (mine has started to wear away), maybe some TPU through my 3D printer would work.

      1. A breakout board just takes the pins in the receptacle and provides test points for them. USB-C, being a multi-role connector, would need to be terminated differently (not a pair of pulldowns, but a pair of pullups) if it’s used as a host or power source port, instead of a device port or power sink port, so it makes no sense for a breakout board to have them hard wired in.

        The decision of which termination to use (pull up, pulldown, or dual-role toggle) is made by the system designer, and should, in this case, be manifested as a pair of resistors on that breakout board, between CC1 and GND and CC2 and GND.

  2. i would use a mini-usb port as i and i think “we” we have lot of such cables hanging around, moreover, the connector is more stress resistant than the micro one.

    But yes, you loose the symmetric aspect of usb-c which is the only value of such choice in this project.

    1. Uh… no.

      Mini-USB was intended as a replacement for regular USB use cases and there’s a reason why it was quickly replaced with Micro-USB after it was misused in the market..

      All versions of Mini-USB are mechanically flawed with insertion ratings between 1,000 and 5,000 insertions. Additionally the contacts on Mini-USB were such that the port on the device was more likely to fail than the cable.

      Micro-USB is rated at 10,000 and it inverted the contacts so that a failure is more likely to occur in the cable. Micro-USB also has a passive latch to reduce the stress on contacts.

        1. I’ve broken a couple of micro-USB cables, but none of the ports in the devices. I’ve worn out 3.5mm headphone jacks, and mini-USB jacks. I’ve broken some of the big old Apple connectors. There’s definitely a selection bias here though: the number of insertions and removals the micro-USBs withstood outnumbers all of the others. So far my USB-C ports are holding strong, but they see less action than their peers as I’m charging my phone with Qi these days.

        2. This is more common with surface mount sockets, and especially more common with people who are rough on cables and sockets. I’ve sold products with these in them, and those with failures always have signs of abuse. . Scratching around the socket, impact marks, a stretched socket from trying to insert it backwards etc. I never saw one fail that showed signs of use but not abuse.

          Back when phones used them, I could go five years on a phone. (And did) my wife needed a new one every 18 mos. She’d plug it in and drop it, or if she didn’t have her glasses on she’d try it backwards. All this is anecdotal, but it perfectly matched what we statistically saw in the product.

        3. That has also been my experience with micro USB on smart phones. Every one of my phones has had the charging connector fail after about two years, maybe 1000 cycles.
          The other problem with any USB connector is that they are uncovered and easily get contaminated with fluff from the pocket.
          A small jack plug with a cover would be far more satisfactory

    1. That’s exactly what I was thinking, and integrate the charging end with a mouse mat. Now where did I put that wireless charging kit I bought from AliExpress and never used…

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