after charging my dead battery on my 95 f150,the truck started on its own

Did you reverse the polarity on the charger connections to the battery? + to - instead of + to +?

Haha I have had this happen with my trooper...replace your negative and positive wires they are cheap but first measure them so you know the length to get. I went through 4 starters and 3 alternators in 1 year. Stupid me didnt think electrical after all that. Anyways your batter is getting a spark from wires exposed due to cracked sleeves, being old, or even say you had replaced a part and hit the wires sometimes you can pull that sleeve off and expose it. But .one was from having to replace those parts so much the wires had crumbled and I never saw them due to the tube they are in. Well that area does get hot and I should have looked at the wires after the second replacement. I hope this helps it did for me