If you want better battery life for your Galaxy S4 you could install a Rom, you could just use your phone less, or you could go buy a giant battery for your phone! ZeroLemon has created a behemoth 7500 mah battery. The stock battery is 2600mah and last me all day. This battery has to last days or for some even a full week. If you don't like to charge your battery the ZeroLemon 7500mah extended battery may be for you.