Hey guys. I have the first generation MacBook Pro that they brought out with the Intels, so it's maybe 5 or so years old. I have never had any issues but about a 6 months ago I did a battery replacement, well the new battery has never seemed to hold much of a charge and I am constantly informed to service battery (I assumed it was a glitch of some sort since the battery was newer). My charger plugs in and charges for a few minutes but occasionally the light will dim and almost go out, it then stops delivering a charge. The display also shows 40%+ battery charge but my MacBook will randomly go to sleep and when I wake the display it says 0% left. Is this a battery issue or maybe a charger issue or is there something more serious happening with my computer? Any help you guys could give would be extremely appreciated!