So I have a 94 M20J with a 28 volt system. I would like to have my iPad and ADS-B Receiver plugged into a USB plug. Problem is, I think my cigarette plug is 28 volt.  I saw a usb charger by mygoflight that is supposed to accept 28 volts but it has received really bad reviews. A couple people have even stated that it destroyed their iPads and Stratus receivers...   Thoughts ?