2008 Unibody's battery goes from 94% health to 50%??

[Tronic]

Something weird just happened that I can't figure out. I have a 2008 15" Unibody (with removable battery). I was using it unplugged and it was about at half health when all of a sudden it died. I hit power and it starts up and dies. Try again and it dies. So i plug it in and it starts up. Pull up coconutbattery which surprisingly says my battery charge is at 42% and my battery capacity is at 50% (50% is 2338 mah out of the original 4600 mah). Last time I checked coconut battery I had a capacity of approximately 95%, which was around december. How could it have dropped so drastically so fast? I have 162 cycles on it within 23 months and typically leave it plugged in sleeping since I just graduated and haven't needed the mobility. I haven't calibrated in a while but I don't see how that could have dropped the battery capacity. Will leaving it plugged in for the majority of the last few months kill the battery this fast?

 

[Tronic]

Ahh, just noticed my status bar battery icon says "Service Battery"

Service Battery: The battery isn’t functioning normally, and you may or may not notice a change in its behavior or the amount of charge it holds. Have your computer checked by an Apple Authorized Service Provider (AASP). You can continue to use your battery before it’s checked without harming your computer.

I can take it in, but anyone have experience with this?

 

[iLog.Genius]

Pretty typical for a dying battery. You can try to calibrate it, but I'm afraid it won't really do anything in terms of improving battery life. It looks like you're going to need a new battery.

 

[GGJstudios]

This should answer most, if not all, of your battery questions:

Apple Notebook Battery FAQ​

 

[SOLLERBOY]

My 08 unibody MacBook started doing this too. If you charge it fully and use it without sleeping or turning off it is fine but if you use it partially and go back to it it dies. Only had 120 cycles.

 

[Tronic]

Taking it in tomorrow. Will let you know what they say.