Went to start up my truck this morning and it made no noise, didn't turn over. Electronics weren't working and made a rapid clicking noise so I figured it was my battery. Got a jump and let it run for a bit, then turned it off. Started up fine. Let it sit for a few hours while I went out and bought a new battery, when I came back it started fine and my battery gauge was in the middle. Nothing that I know of was left on that could have drained the battery.

Any idea what's going on? It's a 2003 F150 7700.

 

CCA...put the new batt in ...

 

Alternator could be acting up but most likely needs new battery