Experiments to investigate the performance of a thermoelectric cooler box powered using a solar panel with a mini pin fin as the heat removal unit was conducted at the un-condition ambient temperature. Due to solar power, the power given to the thermoelectric on different days was different. However, the power on the day of the experiment was nearly stable because the solar panel was connected to a battery. The parameters tested were the cooler box temperatures and COP (coefficient of performance)and there were four Cases examined in this study: Case A (the cooler box was empty), Case B (the cooler box was filled with water of 3000 ml), Case C (the cooler box was charged with 6000 ml of water), and Case D (the cooler box was filled with 9000 ml of water). For these experimental conditions, the maximum COP was 0.51. This was obtained for the run with 9000 ml of water. Increasing the water volume raises the temperatures inside the cooler box and the optimum performance is discussed.