The system is based upon STBCFG01 IC which is a Switched mode single cell Li+ battery charger with OTG boost, voltage mode fuel gauge and LDO. The aim of the system is to make a low cost, robust and highly efficient backup extender for smartphones which will fit on the phone like a backcover. The back cover will have a battery of its own to provide the extended backup. A push switch is used to provide the control to the user for turning the system on and off and also for selecting between phone charging and backup battery charging. A LED based display section is integrated in the system to indicate the level of battery.