Hello all. Very interesting discussion. I have had the same situation on 3 controllers and all three simultaneously allowed smoke to escape at the same time. They were the 100/50 models, and were the Chinese version made by Fanguspan. Before you jump in and say "ah ha! Made in China, eh?", please listen to what caused them to blow. It was all my fault. I wanted to switch the dial to another battery setting because I was experimenting on which was best suited to my LiFo batteries. I shut off all the circuit breakers leading into the 3 controllers and then turned off the battery switch. Somehow, I got distracted when turning it all back on, and turned on the solar panel breakers first, before the batteries. Some have told me that theirs have survived a brief mistake like that, while others like me haven't been so lucky. I have 3900 watts of panels on board my boat, and when this happened I was in full sun, so maximum power was coming to each SSC. The smoke was quite quick to appear! However, I was too late in getting the panel breakers off, and had no working SSC's any more. Being a packrat, I didn't toss them away, and I am happy to come upon this article and what happened inside the boxe. I am not sure my fuses went, but now I will give one the surgery and look. Thanks for the pictures, so I know where to make the incision. (I did try to rip one apart, but it was stronger than I, and that blue plastic didn't tear no matter how hard I tried.) Today the setup has the Victron 250/70 and the 150/85. Of note, the newer ones have provisions for a remote switch that somehow can turn off the SSC WITHOUT closing off any power coming from the panels, or circuit breakers in my case. Why the fuse, if there is one, doesn't pop, is a mystery. However it works great, and I use the 250/70 relay to control possible over voltage on the 150/85 by just turning it off. (The LCD panel can no longer be read and therefore I cannot change any setting manually). Also, the 250/70 with its blue tooth capability, I can now change any parameter I want, including the relay, and what parameters (like high volts) I want to activate it. I will let everyone know what I find inside the box after it comes off the operating table. I seem to remember the smoke coming from the other side of the box, but also at the bottom. But then again, when smoke is coming out, who is taking notes? Further details: The solar panel feed wires go into a box near the SSC's and run thru 3 separate 400VDC miniature circuit breakers, 20amp, 16A and 10A, which break both the positive and negative wires. My lithium bank is 800ahr wired at 24v. Cheers