I am a trained solar generator builder. I've built many systems and got great results. I bought this lightweight 500 watt pure sine wave inverter for small loads in a truck trailer to charge Dewalt batteries, run a coffee grinder and use a laptop. It will only charge a 20V Dewalt battery from its charger and if you connect anything else the inverter will shut down and report ERROR. I even increased the thickness of the cable that runs just 3 feet to a heavy duty deep cycle battery. The cable that came with it seemed flimsy and didn't even work when I plugged it in. A cheap modified 39,300 watt sine wave inverter I bought from Harbor Freight worked better than this one. That thing is garbage to me. Don't buy if you want something that works as advertised. It's not like this!