What Size Power Inverter Do I Need? The size you choose depends on the watts (or amps) of what you want to run (find the power consumption by referring to the specification plate on the appliance or tool). We recommend you buy a larger model than you think you'll need (at least 10% to 20% more than your largest load). Specification: 1. Solar Panel 18V18W: Power: 18W± 5% Size: 420x280x2.5mm DC output: 12V/1.5A USB output: 5V/1.7A Weight: 0.7kg Type: Mono Solar Panel Material: Aluminum substrate Output accessories: DC cable + DC alligator clip 2. Modified Sine Wave Inverter : Features: * 4000W vehicle power inverter, convert DC 12V to AC 110V/220V, the output voltage is constant and accurate. * With 1 universal AC outlet and 2 USB charging ports, it is ideal for charging smartphones, tablets, laptops, game consoles, TVs, car refrigerators, car vacuums, lights and other electronic devices.