In this paper, will be shown and discussed the battery performance of small Unmanned Aircraft Vehicles (UAV) based on the full electric power supplying. The recent small-UAV using the hybrid power systems based on power electrochemical batteries to be energy efficient, have high power density thus reducing weight to achieve the maximum ranges. This paper shows that temperature effect decreasing the conversion efficiency up to 50 %. This could mean decrease in the power density and total capability of vehicular batteries. Therefore, use of UAV and range of application is affected by the variation in temperature. Paper gives brief outline of the investigation of batteries versus temperature effects. The batteries are compared and investigated using experimental method.