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Should I manually turn off my aluminum keyboard and magic mouse when my iMac sleeps, or is there an automatic low-power mode?

( BONUS: How often should the batteries be replaced? )

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up vote 1 down vote accepted

The mouse and keyboard sleep automatically. I've only turned mine off when away for extend periods (e.g. vacation.) I've seen 5+ months battery life (with fairly light usage) this way. If it were my primary machine I suspect ~3 months would be good battery life.

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As of today my Christmas-present wireless keyboard reports 17% battery remaining on its first set of alkaline batteries. That extrapolates to 0% at 105 days; it obviously won't run to 0% so reduce that to somewhere between 87 days (today) and 105.

I am not using any other bluetooth devices; there was a battery life issue - for which Apple releaed a wireless-keyboard firmware update - when the wireless keyboard was used with other bluetooth devices. See:

Answer to your bonus question: For me, not until they die. That looks like about 3 months+ of run time for my usage pattern, the updated firmware, and no BT mouse, based on a sample size of 1...

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Your usage pattern is ... ? And, am I supposed to turn it off at when the iMac is off? I just installed the battery life update. – Moshe Mar 23 '10 at 18:01
Probably 8-9 hours a day, not necessarily typing-intensive, but on and active. I don't shut my keyboard off, ever (except a couple of times, just to watch the reconnect process). I don't know how much battery run time would be extended if I did, but at 3 months/set of batteries, I'm not motivated to do so. I suspect the KB goes into a low power mode when it has been idle for a while but that's a guess. – JRobert Mar 23 '10 at 19:11
+1 for first answer. Chris gets the check for an affirmative answer. Funny that your estimates match up. – Moshe Mar 24 '10 at 1:38

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