Why does a Microsoft mouse accept two batteries even though it works just fine on only one battery?


Many mouse devices from Microsoft have a battery compartment that accepts two batteries. But the mouse still works even if you insert only one battery. What's going on here?

Yes, the mouse works just fine on only one battery. The reason why the mouse accepts two batteries is to double the amount of time between battery changes! This allows the text on the box to say "Runs for N months without needing to change batteries" for a value of N that is twice as high as it would have been if the battery compartment accepted only one battery.

This is the electronics equivalent of installing a larger gas tank in a car so you can advertise it as "Travels ⟨distance⟩ on a single tank of gas."

Comments (27)
  1. Brian_EE says:

    All of my mice work just fine with no batteries. Presumably the mice you refer to are cordless. That then begs the question - If the mouse doesn't have a tail (cord), can it really be called a mouse?

    For reference: http://www.afrma.org/brdstf_createtailless.htm

    1. poizan42 says:

      Tailless mice are mice too. #allmicelifematters

    2. Gerry says:

      Surely tailless mice should be called blind mice? Or is that only if the tail has been cut off?

  2. rich says:

    I've had three or four wireless Microsoft mice. They always stop working after 6-8 months. You can change the battery, no effect - they just simply stop working. Hard to understand why, since there are no moving parts. Anyway I have now used the same cheap (wired) mouse for years, with no issue.

    1. SimonRev says:

      To offer counterpoint: I picked up a wireless Microsoft mouse for work (I would give the name, but not sure if that would violate the ground rules when the topic of the article is Microsoft wireless mice).

      For the first decade it needed battery changes every 9 months (pretty exactly). For the last couple of years it has been closer to 4 months though. The mouse is still going strong, although the rubberized grip has all worn off as well as all the paint where I hold the mouse and the ridges on the mouse wheel have worn smooth.

      I keep thinking it is time to replace it, but every time I look at the current crop of mice, I don't like them as well.

    2. CarlD says:

      I have multiple Microsoft wireless mice that are over a decade old and still going strong - including the one attached to the computer on which I'm typing this. Perhaps the quality has declined and only decade-old mice have decade+ lifespans.

    3. Pierre B. says:

      To add to the anecdotal evidence, I've owned mice from several manufacturers and the Microsoft mice have been the sturdiest, longest lasting ones. The other ones (I won't name them) had various quality level, but non lasted as long as Microsoft ones. Plus, MS mice do not come with those weird add-on driver configuration panels. (The worst being an drawing tablet, which requires its settings app to be run as administrator! Are we in 2017? Are we in Windows 10? How can QA not catch that the settings panel requires elevation?)

    4. zboot says:

      I had a BT MS mouse, which finally died after getting crushed a few moves ago. It lasted about 7 years. The best wireless mouse I ever had. It took me a while to find a replacement - that particular mouse was discontinued years prior to its replacement. I feel I replaced batteries about once a year - less depending on how much work I'd been doing at home vs away (work/school) where I either had dedicated docking or just used the touchscreen/pen.

      The mouse gets less use now due to touch/pen input improvements.

    5. JoeD says:

      I have not had that. I have the MS wireless mouse that comes with the MS Sculpt keyboard and I have to change batteries maybe once a year.

      The one thing I do not like about the MS wireless products is that the dongle is "hard wired" (for lack of a better word) to the mouse/keyboard. If you break the dongle or lose it, you have to toss the mouse and keyboard - they are useless. You can't get a replacement dongle. (As you can tell, this happened to me... something hit the dongle and it broke off in the USB port - left me with an orphaned mouse and keyboard.)

      1. Mary B says:

        the dongle is hard-wire(less)ed so they can be pre-paired at the factory, for both convenience and security; that way your mouse doesn't move the cursor on your co-worker's screen

  3. William says:

    Acknowledge all the mice!
    #allmicelifematters

  4. Another reason for adding more batteries: to make the mouse heavier. People like hardware to feel solid, not flimsy, and weight is a part of that. My corded mouse here actually has a weight in it - a piece of steel that obviously has no function other than to add weight.

    1. ErikF says:

      I've had the unfortunate experience of having to use a touch-sensitive wireless "mouse" (it looks more like a rectangular prism) provided by a certain fruit company that seems to have been designed by aliens and has the same form factor as a smart phone, only a bit thinner. There are no mouse buttons at all (the primary mouse button is achieved by pressing the 'top' of the mouse, and the secondary button is a hit-or-miss affair where you have to press the 'side'), and the scrolling function is backwards to every touchpad I've ever used; I don't trust myself to even complete click-and-drag operations with it! Every time I use it I am reminded of how much better even the cheapest PC mouse is compared to it.

      1. Zan Lynx' says:

        Some of us *like* the Magic Mouse.

  5. Ray Joyal says:

    I have a mouse made by that other company... it takes two AA batteries... lo and behold... it works with just one installed!

    The way to tell: if both batteries are installed the same direction, if both + terminals pointing the same way - you'll probably only need one battery. If one battery is inserted + end first and the other battery is - end first, it needs both.

    I always thought it was weird how the batteries were installed in this one...

    1. Mary B says:

      actually, Microsoft has a patent on building mice so the batteries work whichever way round they are ;)

  6. sergegers says:

    Still unclear yet why Microsoft don't equip the mouses with four batteries or more.

  7. alegr1 says:

    Microsoft mice also use the worst possible LED for such device - blue. Compared to an infrared LED, it produces less than 10-20% of image sensor response for the same power consumption. I can't wait for blue LED to get out of vogue.

    Don't buy Microsoft BluTooth mouse. They just can't stay paired to a laptop. Apparently, that's known problem.

    Also, steer clear of their Intellipoint driver. It will give you insane scroll speed. That's been known problem since forever, and I just can't be bothered to check if it's fixed now.

  8. ZLB says:

    I still miss my old Microsoft Starck mouse. I had it for years despite being slammed down and thrown at the wall a few times...

  9. I have to admit that I use a Logitech mouse (the Master MX), which is very good, except for the software (Microsoft mouse software is superior).

    But since 1999 or so I have used and loved my Microsoft Internet Keyboard Pro. I am writing this text on it! Best keyboard ever.

  10. Steve says:

    My mouse is so posh that it needs no batteries at all and plugs straight into the machine!

    1. xcomcmdr says:

      Aye ! No maintenance, no batteries, and years upeon years of service ! :)
      Yes there's a cord, but so what ? It's hardly an incovenience.

  11. BZ says:

    A bit off topic, but strikingly, this is the first time I've ever seen "mouse devices" as a plural of mouse in the wild. Previously I've seen it in advice, always citing the Microsoft Manual of Style for Technical Publications. I guess it makes sense that I first encounter it from a Microsoft employee.

    1. I didn't want to start an argument over the plural of "mouse" so I used an alternate wording. Didn't know that it was the Microsoft style recommendation.

  12. xpclient says:

    My MS BT Mouse has only 1 battery (thanks to the amazing Bluetooth Low Energy). Unfortunately the battery lasts longer than the mouse whose wheel stopped working just after 8 months. Also all warranty pages and sites are intentionally broken so MS doesn't have to honor the warranty.

    1. I like how you default to the conspiracy theory.

  13. Viila says:

    My pet peeve is battery operated devices without strict weight and volume limits that take AAA batteries instead of AAs... You get way under half the capacity for the same price. Yay.

    My non-MS brand keyboard for instance takes 2xAAA for whatever reason. There would be plenty of space for AAs, and it's a keyboard so few grams wouldn't make any kind of difference. And my trackball from the same manufacturer takes 1xAA, so I can't even share batteries between the two. Have to keep both kinds in stock.

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