The wire on the side is for charging the battery. There is also a 12 volt port and a battery gauge and a switch to isolate the power when it's done charging. Please ask questions if in doubt and please check out my other auctions. I have another one listed with 1000 watts of power. This item is in the category "Home & Garden\Yard, Garden & Outdoor Living\Outdoor Power Equipment\Generators".The seller is "802dogger" and is located in this country: US. This item can be shipped to United States.