This is going to be something your engineer friends will like. If you’ve ever tinkered with electronics at all, you know that it can be messy, but when you’re dealing with car batteries, it’s usually really straight forward. When it’s trash you throw it out, or you can charge it with a machine that will put it at a decent level again. This is an easy trick used by getting a BoostPack out of a few items and replacing your car battery With 12V Battery Capacitor. It’s an easy trick and could just end up saving you lots of money.