I know some have blown the charging fuse on their semi-integrated battery by accidentally sticking their key in the charge port. But I found out the hard way it is also possible to stick the charger's barrel connector in at an angle shorting the center pin to the barrel and blowing the fuse. Fortunately I was able to get the battery apart and replace the mini-fuse. I understand the latest batteries have soldered-in fuses. In that case, I think I would just add an external fuse holder.