Sorry for the long winded post, but I'm not the greatest with electrical and could use some help diagnosing this.

The car has been getting harder to start over the past week or so, cranking a bit slower, like the battery was low….but I just attributed it to the cold weather. So yesterday, I fired it up and let it warm up for about 5 minutes. As I started down the street, it just died….kind of sputtered out like it was running out of gas. Turned it over and it fired right back up, but as soon as I touched the gas, it just died. Tried one more time and it started again, but would only idle for a few seconds and die. I did notice that every time I cranked it over the battery was getting quite low and the run time would get shorter the lower the battery got. So I pushed it back home..(how embarassing)..and tried to jump start….but that didn't work either and now the car wouldn't start at all. I checked the battery, and it was quite low so I put it on a charger overnight. This morning I hooked the cables back up and it started right up and ran great, no problems at all, like nothing happened.

The battery is about 4 years old. Could it be the battery is not taking a charge from the alternator? If that's the case, then shouldn't it only be hard to start, but still run after it's started?

Or is the alternator not doing it's job by keeping the motor running and charging the battery? I'm leaning more towards this as the problems as it seems that I have been running on the battery...and as the battery died, so did the car.

Thoughts anyone?