Smart phone services have become all encompassing in these modern life activities. These phones operate with batteries that provide the necessary electrical power. The batteries’ stored energy often got used up; and the conventional electrical power charging sources like public power supply, generating sets, solar devices among others are not only unreliable but most times totally unavailable in some villages and camp settlements. There was then the need to produce simple, inexpensive and easily accessible battery chargers for the phones. This paper therefore studies and analyzes the performance of a locally-made, off-grid and renewable energy power phone charger. The device output voltage, current and hence power has been tested at varying degrees of temperatures. Finally it was tested with different heat sources like, charcoals, Gas- burner, kerosene stove, wood stove, and Camp and Barbecue fires for heat source efficiencies. The results prove that charcoals and gas-burner heat sources are the most efficient heat source for operating the heat-smart- phone charger.