mattk68
always plugged in and usually in sleep mode.
So it was always plugged in, never discharged, and was never really OFF, just in sleep mode.
Sounds like you got some half-true 'advice' from some people.
It DOES shut down when fully charged and you cant "overcharge" your macbook....., and the "others" were correct that your battery should be cycled every couple weeks at least.
what they didnt tell you is "plugged in and OFF is one thing.......plugged in ALL THE TIME...AND in sleep mode (for years)......NO!" 😢
Heres some info for the "next battery" :
Keep it plugged in when near a socket so you keep the charging cycles DOWN on your LiPo (lithium polymer) cells / battery.
*Contrary to some myths out there, there is protection circuitry in your macbook and therefore you cannot 'overcharge' it when plugged in and already fully charged
If you leave your macbook plugged in all the time, take it off charge and drain the battery down to 15 or 20% every couple of weeks or so.
LiPo (lithium polymer, same as in your macbook) batteries do not need conditioning. However...
LiPo batteries do NOT like to be dropped down to 15% or so often,....key word being "often"
A lot of battery experts call the use of LiPo cells the "80% Rule" ....meaning use 80% of the charge or so,.. then recharge them for longer overall life.
Never let your Macbook die from power, you can corrupt files that way, and the batteries do not like it.
**Also new evidence suggests that sudden loss of power can adversely affect data on a SSD (solid state drive).....again, dont let it ever shut down from total power loss
The only quantified abuse seen to LiPo cells is instances when often the cells are repeatedly drained very low.
Contrary to what some might say, LIPo batteries have an "ideal" break in period. First ten cycles or so, don't discharge down past 40% of the battery's capacity.
Same way you dont take a new car out and speed and rev the engine hard first 100 or so miles.
*Also, if youre going to store your macbook away for a few weeks or more,... make sure it has at least a 50% or so charge.
*Cycle count / use/ lifespan is one thing that cant be countered.
Proper treatment is another thing. Just because LiPo batteries dont need conditioning in general,.. does NOT mean they dont have an ideal use / recharge environment. Anything can be abused even if it doesnt need conditioning.
Just use and enjoy your new macbook,
From Apple on batteries:
http://www.apple.com/batteries/notebooks.html
http://support.apple.com/kb/HT1446
but really all you would keep in mind is --"consider 15-20% is the same as 0% and recharge it"
and best "tip" is if its near a socket, .....plug it in as long as you can (especially at home) since cycle count on the battery are the "miles that wear out the tires (battery)"