A few weeks ago my mac started showing a "service battery warning." The charger would behave erratically, sometimes charging, sometimes not, and sometimes only showing a dim green light. In addition, when charging sometimes my computer would seem a bit hotter than I remember it.
So, before heading into apple and dropping $200 on a new battery, I googled the internet and found some suggestions. Resetting the SMC seemed like a harmless suggestion and indeed, the "service battery" message has disappeared since performing the reset. While I was at it, I also reset the PRAM (I don't know if this did anything useful).
While I'm not an expert in said things, both resets are harmless and can fix issues related to:
- Speaker volume
- Screen resolution
- Startup disk selection
- Fans/Temperature
- Battery/Power
Note: Resetting the PRAM may loose some of your basic settings like keyboard rate, time zone, and mouse click speed. I didn't notice any major frustrations from doing these resets.