I think I saw a 300 watt 12v on ebay a few years back with a positive and negative input from battery banks. I Imagine one would need a smooth steady flow of 12v and not 13v or fluctuation. Have you guys and gals ever heard of such a PSU being sold or made? It would only need to put out 12v and 5v. I do know what an inverter is and that it might be a power drain to run one all day and night as well. Any thoughts on this would be splendid. 😱