So.. I posted this yesterday and got great advice..But I still have a problem! Below is the first question. I have a ford explorer that recently wouldnt start. I have one of the black and decker instant jump start things (that you charge in the wall) and I tried it but it didnt start from it. I dont think the charger was all the way charged so that could be it (its plugged in now and will try after its charged long enough) but I want to know if there are any signs that you can tell if its the alternator and just a battery needing to be replaced? NEW ISSUE: I charged the battery booster thing for 24 hours or so (the directions say to charge for 48 hours but I wanted to try after 24) It has a green light that lights to show how much its charged and when I connected it to the battery and tried to start it a few times and it just wouldnt start. It makes the same sound that a car normally does right before it starts but the engine never turns over and starts. When I was trying it I had another thought! I was coming home late the night before the car wouldnt start and the gas was almost on empty (I was almost home before I noticed it) and I decided to fill up the next morning. Is it possible that Its just out of gas and not the battery? Im not sure if Im describing it properly so If there are any questions I need to answer ive not gotten please ask. Oh.. And the whole reason behind the charger thing is that im not sure that the cord I was using it was the proper one (yes, im blonde and a bit.. slow haha.) and after I tried to start the car a few times with the battery thing it showed that it wasnt charged. Any suggestions would be great.