Inverters do draw current even when not under heavy load. When I bought a ranch in WY several years ago I bought a generator so I could use power tools since there was no electric to the property. Many times I had problems getting the generator started. I bought a 2000 watt inverter. Best money I ever invested. I had enough power anyplace on the ranch to run power tools. Just pop my PU hood and connect the inverter. I use a small 150 watt true sine wave inverter in my MH for my computer etc. when off the grid. Having a solar panel helps to keep the batteries charged. If I camped off the grid for longer periods I would install large solar on my MH roof.