Indonesia is the largest maritime country in the world with 2/3 of its territory is an ocean that stretches from the northern tip of the island of Sumatra to the southern tip of Irian Jaya. On the island of Bengkalis itself, the majority of the population work as fishermen, because the island of Bengkalis is surrounded by the ocean, due to the fact that to produce a lot of fish catches sometimes fishermen on the island of Bengkalis travel a distance to find fish that are quite far away, sometimes the catch of fish spoils because fishermen use coolers from ice cubes has a melting time limit caused by several factors, one of which is the heat of the sun in the ocean, this causes sometimes fishermen to experience losses, these factors can be overcome by using an electric-powered cooler, but to buy an electric-powered cooler, fishermen on the island of Bengkalis have not been able to afford it due to buying coolers and power plants diesel power that spends quite a lot of money, therefore the author wants to make a tool entitled the design of a 12 volt DC battery converter voltage to 220 volt AC for electricity cooling fish on board, which serves to relieve the burden of fishermen in accommodating fish to keep them fresh until they land
