I have a set of 400 watt panels 2 good quality 800 max but I've never seen them go much above 740 watts as I'm in northern Canada , Had an initial issue, burnt a circuit on the main high current path on the board, it was a fluke it was a not 100 % connected solder point once the amperage hit about 40 amp it Lost its hold and smoked, I .was mad but weighed the hassle of shipping it back etc etc , But being an electrician I went in and voided the warrantee to have a look , the fuses were fine good quality parts Capacitors and VRegs, fan, diodes etc were awesome quality, and the soldering was fine good quality this was a pure fluke, I re soldered the one transfer bar and all was good this was a one in a million fail I'm happy I got it, because I saw all the quality and strength this unit has . I will be buying another for sure! I've since turned it to charge 24 volts from 12 and added another 400 watts its working wonderfully and it should for years . Very happy , I've worked with many cheaper chinse controller's and there is a difference , easy to configure to apps from laptop to fine tune etc.. all GOOD Guys .