I have the exact same problem. Didn't use to be the case but within the last 6-8 months it's suddenly started to happen.
I did discover the following, though - my batteries are actually fine! The keyboard doesn't wear out the batteries - it just reports them used up and shuts down! I checked the Duracell Power Indicator on the actual batteries and they were at 75% power remaining!
For some reason they keyboard chooses to shut down at even 75% battery power remaining - absurd and intensely annoying. Until I discovered this I must have tossed out dozens of almost fully charged batteries thinking they were depleted!
Not sure what to do - from the postings here it doesn't seem that a new keyboard will solve the issue :-/
Anyone checked the power on their batteries and experienced the same as I?
I had my wireless keyboard for several years before this happened. Literally, the keyboard was fine one day, the next I had to replace the batteries. From then on, I replaced the batteries EVERY morning. It was simply an addition to the morning routine: wake up computer, replace batteries, get coffee, go to work.
Like you jwrusa, I checked the batteries in my charger, my mouse, or some other battery eater. They were dead as doornails. I came to the community and looked up what others had to say. No, I hadn't updated or upgraded anything - at least not immediately before this occurance. In fact, the updates and upgrades had ALL been performed, and the keyboard never wavered; it worked just fine after each of them.
The only thing that had changed in the overall scheme of things was that I had added an Air to my desk. As odd and stupid as it sounds, every time I add a new computer, one of my older ones pitches a hissy. But, for the Air, I did get AppleCare, because I take it with me to all kinds of places.
So after looking through this community and a couple others, I decided that while the end result was the same - dead batteries - the symptoms were different. I did what I should have done months before: I called Apple. Apple told me the keyboard was covered under my AppleCare plan for the Air. They gave me a couple choices:
1) Apple would send me a box, into which I would put the keyboard, they would pay to ship old keyboard to them and ship me a new keyboard. At no cost.
2) I could drive the keyboard to an Apple Store and they would give me a new keyboard. At no cost.
My nearest store is about 110 miles away. Any excuse to go to the Apple Store is good by me. So I made an appointment and drove down to the store. I got there early enough to browse a bit, met my person, handed over the keyboard - with batteries so he could check them. He played with it and, yup, batteries were dead. He went into the back room and came out with a new keyboard AND a new set of batteries!
No muss, no fuss, just deal with the problem. Which is why I have had Apples since the Apple II series.
this post belongs to 2009 and since then apple has released 3 major updates to OS X. this issue has still not been fixed!
SHAME ON U APPLE!
while i am typing this i just got a "low battery" sign on the screen for my keyboard! it was at 33% a few minutes back! and now its 18!
i am having to replace the batteries on my keyboard and mouse every 3 days or so. I AM NOT REINSTALLING MOUNTAIN LION! i have done that too much since Lion came out.
we dont need Maverics or any other new OS, we need the old ones to be fixed!
Today i bought a set of apple rechargeable batteries. RIght now i have the magic mouse and apple wireless keyboard piared to my macbook pro. in about 7 hours... the keyboard battery has stayed to its original 80% and the mopuse battery has reduced to 26% from 60% ! okay... on double check it now indicates 29% !
all this while the machine has been on sleep.
now what i'm gonna do is remove the batteries of both and put them in again...
let see what happens...
magic mouse 55% !!!
keyboard stayed on 80%
now i am gonna swap the batteries....
magic mouse 53% (in the keyboiard it was 80%)
keyboard 67% (in the mouse it was first 60, then 26, then 29 and then 55!)
now i am gonna put them back into their original devices...
magic mouse 54 (close to the last 55 it has shown)
keyboard 77 (close to the last 80 it had shown)
i understand about the values calculated by the smc, but this is nuts!
also, the pattern of reporting remaining battery indicates that each device has a non standard way of calculating it. why else would the same batteries indicate a different charge on different devices?
there have been times when using use and throw batteries i have got one device indicating that the battery has drained and the other indicating a more or less consistent percentage remaining about removing and inserting them in each, several times. this is so weird!
I HAVE INVESTED NEARLY $6000 IN ALL MY APPLE GADGETRY BUT I HAVE NEVER GOT PEACE OF MIND USING ANY.
d*** the bluetooth drivers.
APPLE.... IF IT AIN'T BROKE... DONT FIX IT!
I came here with a different issue. I put brand new batteries into my keyboard yesterday. Today I got the low batteries message. But I've checked and both the KB and MM list 100% charge. I was thinking it was an issue with My MacPro, but reading this I'm thinking it's Lion, I use the same KB & MM (at separate times) on an iMac with Snow Leopard without this issue. But now I'm wondering if I've been tossing perfectly good batteries for weeks.
My wireless keyboard's battery life seems to be degrading over time. I purchased the wireless keyboard in Jan 2013 from Best Buy and it had great battery life (used rechargeable batteries). It would go weeks without a battery swap even with me forgetting to turn the keyboard off. Currently, whatever battery i install will last only one day at best before I receive the low battery warning. It's not the battery because even brand new rechargeable batteries don't last either. What I did discover is that if I remove the batteries, the battery gauge resets. It goes from 15% back up to 93% on the same battery. Turning off the keyboard via the power button does nothing to help. What's the story here and how do I fix this without having to mess with the battery door each day I want to use this? Am I using the keyboard wrong ? My apple track pad seems unaffected and works fine.
To all with the battery eating problem. I too had this issue. It got to be a morning routine:
Wake up computer
Remove batteries from charger
Replace yesterday's batteries in keyboard
I also wrote this community and got many replies regarding upgrade issues (I am working on a Mac Pro Tower running 10.6.8), adding a BT mouse into the mix, zapping PRAM, etc.
My keyboard was a couple years old, heavily used, never had a problem. I went through several upgrades in OS, a couple of wireless mouse changes, and a trackpad, plus a Cintique from Wacom. Never had a problem. Simply one day I had to change batteries, then the next day, next day, next day, until it became an additional morning routine.
Finally I called Apple. The tech had me try a couple things, none of which made any difference. They replaced the keyboard for free. As I said, the keyboard was a couple years old at that point, totally off warranty. The tech was wonderful to deal with. He gave me a choice of coming into a store, or sending me a box with replacement. Our nearest Apple Store is a little over a hundred miles away, but any excuse is good. Although it took me a couple months to get there, when I made the appointment and gave them the case number, the store pulled it up and had my keyboard waiting for me. Couldn't have been simpler. The hardest part of the whole replacement has been to get used to new, springy keys.