Okay, so I've put these SSR-80DA relays through absolute hell - greenhouse conditions with crazy temperature swings, high humidity, you name it. And guess what? They just keep on ticking!
The DC-AC version uses a MOC3063 opto-TRIAC combo that's surprisingly robust. I've torn apart competitors like DMWD and Fotek, and honestly, these hold up just as well if not better.
Pro tip: Always go one size up from what you think you need. These can handle 80A, but I wouldn't push them to the limit without active cooling. The thermal pads help, but let's not get crazy.
Construction is decent - beefy traces, okay solder joints. Some units are potted, some aren't. It's a bit of a lottery, but they all perform.
For the price? Absolute steal compared to designing your own switching circuit. Just don't expect aerospace-grade perfection.