I also got a cigarette lighter socket charger for a USB hub (cheapo Amazon purchase). It seemed to work fine with a relatively fast charge, but I have recently stopped using this device because I am not sure what voltage the USB hub is charging at and don't have the packaging/specs for the hub. I'm concerned that it is at a voltage my devices (phone, tablet, bluetooth speaker) aren't equipped to handle. I suspect this is something it is more economical to spend a little more on at the front end to make sure it has an adequate built-in transformer than on the back-end for a phone battery that dies prematurely. I recently replace my relatively ancient, 5 YO android phone because the battery wouldn't hold a charge for very long anymore. Not sure if boat charging was a contributor, but I'm hoping I can make the new phone last that long.