*fingers crossed* So far, so good! Haven't fiddled with a load over 200W yet, but it looks pretty decent. There was an odd hum and high frequency for the first few minutes after plugging it in and turning it on, which I either got used to or cleaned up on. It seems to be quite effective, my new 24 volt system turned out to be a lot better than I ever imagined getting rid of the 12 volt system. Don't be embarrassed or frustrated at the thought of converting your 12V 400Ah battery to a 24V 200Ah battery as the watt hours are the same and higher voltages are more efficient and produce a lot less heat ! I will keep this updated should anything change.