Most people have some idea of how heavy piece of electronics of certain size should be, many fake chargers/supplies are surprisingly lighter than that (sadly, e

Most people have some idea of how heavy piece of electronics of certain size should be, many fake chargers/supplies are surprisingly lighter than that (sadly, even some known original Nokia and Samsung chargers seem too light to me, so this is not valid test) Good thing to look for is presence of some name of manufacturer. Absutely no name => unsafe, Obscure or semi obscure Chinese manufacturer => probably OK, Well known global brand => depends (and depends on what the charger is for, nobody is going to manufacture fake Delta-branded charger for iPhone, but fake Delta-branded power bricks for various networking equipment are fairly common). Power quality on input is certainly an issue, but only for totally out of spec inputs. Small wide input SMPS (like these for laptops) just run hotter on lower voltages because of their internal construction (lower voltage => higher current => higher losses).