Macbook shuts down when it reaches 0% battery life

I'v had my macbook for about 2 and a half years now and whenever my battery reaches about 0-4% it shuts down. Normally it should go to sleep and then shut down, however mine just shuts down.

However the weird thing is that if my macbook shuts down when i have 4% battery life left then when i start my macbook up again it says i've got 3-4%. Therefore my macbook is not shutting down because it has run out of battery life.

So far I'v
1. reset the PRAM
2. calibrated the battery (3 times in the past 4 days)

Other Info
1. I'v had 515 cycles
2.my current battery capacity is 4938 mAH, which is down by 2% from the original battery capacity.

What can i do to prevent my macbook from randomly shutting down at 0-4%
how long does a normal macbook battery last?
do i need a new battery?

Fantastic battery you have there! 515 cycles and it still has 98% of its original capacity. (If that's really correct.) Apple specs say the battery has been depleted after 300 cycles. As you can see you're way ahead. New battery? Just keep using the one you have until it won't satisfactorily charge or maintain its charge any longer. I wouldn't worry about the machine shutting down at 4%.

Regards.

ah ok, thanks for the quick reply.

Yeah I'v been doing some research on macbook batteries and most websites said that they should last about 300 cycles but i thought it was either a mistake or i was misunderstanding it or something. lol

If it was me, I just wouldn't let it get to 4%. Seems like the easiest fix.

One thing you have to understand about batteries is that they are not an exact science. The remaining battery life is calculated by the computer based on usage patterns and limited feedback from the battery. There is no metering mechanism built into the battery like there would be in a fuel tank in a car. So, although the computer may think there's 4% remaining, it might drop off faster than anticipated.

This is why Apple recommends "calibrating" the battery periodically. Basically what happens is that the computer tries to determine the battery capacity based on how long it lasts through a complete cycle.

Ah ok thanks for the info cwa107.

Another thing that I've found is that if i close my macbook it goes in sleep mode, about 15- 20 minutes later it would shutdown. This would happen if I have the AC power plugged in too.

In order to keep the battery healthy David Apple recommends that you regularly calibrate the battery, therefore I do need go to 4% and below…

shahvikram123 said:

Ah ok thanks for the info cwa107.

Another thing that I've found is that if i close my macbook it goes in sleep mode, about 15- 20 minutes later it would shutdown. This would happen if I have the AC power plugged in too.

In order to keep the battery healthy David Apple recommends that you regularly calibrate the battery, therefore I do need go to 4% and below…

Click to expand...

I would recommend resetting the SMC:

Apple Portables: Resetting the System Management Controller (SMC)

In order to keep the battery healthy David Apple recommends that you regularly calibrate the battery, therefore I do need go to 4% and below…[/QUOTE]



On my Macbook the warning comes on at 10%. Maybe yours is different. But at the Apple site it says to get it "low".Mac OS X 10.4 Help: Calibrating a MacBook or MacBook Pro battery To me, under 10% but above 4% is low.

Yh if you read the article you linked properly David you would have known that your not supposed to connect the AC power once you see the warning. Your supposed to charge it down until your macbook goes sleep by itself.

Once it is in sleep mode it is using its reserve power and in order to fully calibrate your battery you have to leave it in sleep mode until the pulsating light on the front of the macbook turns off…

Therefore you need to go below 4% or 10% or whenever you see the warning…

BTW thanks cwa107, I reset the SMC and it has seemed to work so far…