I n an effort to reduce using CFC (Chloro Fluoro Carbon) or freon as coolersubstance which used on conventional refrigeration system which is usedgenerally. So that the research is needed to find another alternative solution toreplace this substance. Because of that, this substance can be threat ofenvironment by ozone depleting and global warming. One of the alternativesolution is using thermoelectric element or called Peltier. By this research, acooler has been designed, constructed and tested with a box 5.5 liter capacity. Itis called coolbox based on thermoelectric. The used components can be foundeasily at the market. This cooler box system has been tested without or with aload of canned drink 330 mL and this coolbox system uses electric from abattery. In this research, to be focused about the load variation effect to coolboxtemperature, COP (Coefficient of Performance) and efficiency. At this research,the used load variations are without a load (0 mL), 1 canned drink (330 mL), 2canned drink (660 mL), 3 canned drink (990 mL) and 4 canned drink (1.320 mL).The testing time of this coolbox system is 45 minutes for every load variation. Asthe results, it can concluded that minimal temperature in the coolbox reaches 8 oCfor the load variation 0 mL (without a load), 11.3 oC for the load variation 330mL (1 canned drink), 13.7 oC for the load variation 660 mL (2 canned drink),14.8 oC for the load variaton 990 mL (3 canned drink) and 16.5 oC for the loadvariation 1,320 mL (4 canned drink). The maximal of COP result is 1.68 and themaximal efficiency is 54.88 %.