Charger LED and Battery issue

[macinchicago]

I have a MacBook and I have two issues that I do not know how to fix.

1. My battery life will read at about 20-25% and my screen will go black like it shut down. When I double click or hit enter it comes back up and the battery life reads 0%. Why is it doing this?

2. When I leave my computer charging it sometimes blinks between green and yellow, it rarely stays one color

Im assuming that my battery is probably needing to be replaced because when its not connected for a period of time ( maybe a little over an hour) the battery drains faster than I think it should be? Could this be what is causing my previous 2 problems? Thanks

Macinchicago

 

[soberbrain]

1) Try resetting the SMC. Then do a complete charge, complete drain, complete charge. (You should be draining the battery and charging it completely, about once a month.)

2) The above might help this, also download Coconut Battery to check your battery's health. A healthy battery would have about 80% capacity. If it's below that you can consider getting a new battery. Also, if your battery cycles are less than 300 and the capacity is less than 80%, Apple may replace your battery for free.

http://www.apple.com/batteries/