I just replaced my battery with an 800 cc interstate battery 4 days ago because my truck wouldn't start and I figured it was the battery, since it was the original. The truck ran fine for the first 2 days, but the 3rd day it took me a few tries to start it and then today my truck wouldn't start. We jumped it and it immediately started I drove it for about an hour and then when I shut it off. All the electrical was dead. I couldn't even turn my lights on. Is this a bad alternator or do I potentially have some other electrical problem?

to be honest i have been having some slow and no start issuse lately with my X as well ... sometimes for some reason when i turn the key nothing cranks ... but i have power to run the CD player and AC ... i just waited a few minutes in the parking lot and looked at my girlfreind then i tired it again ... I must say is kinda scary ... i think i take my X to the dealer ship it under warrenty still .. So far it has only done this twice with in the week ...
I am gonna check for starter fuse/relay and see if the humidity got in to it .. after all i seem to have alot of foggy windows lately .. i wonder if it could be weather related or just a peice that is malfuntioning

sounds like a loose battery cable.. if you could jump it & run it a while, your alt is working.. these motors require lots of power.. fuel pump, injectors, half a dozen computers, sensors up the wazoo... If the battery cable is loose, all that crap can run off the alt, but there be no charging (or very little) to the battery.. double & tripple check the cables.. twist them, if they even think of budging, they arn't tight enough..

I second the last post. Make sure it is clean. Use a wire brush to clean it and tighten it really good. You shouldn't be able to move the cable with your hand.

I cleaned both the connections and reconnected. It still wouldn't start. The negative appeared lose but I couldn't wiggle it at all. I ended up replaceing the negative and the problem was solved.

cool !