Review on High-Power Buck Converter Step-Down Module - XINGYHENG 20A 300W, DC 6-40V to DC 1.2-36V, Adjustable Constant Voltage Current Power Module with Short Circuit Protection for Charging, LED Drive by Chris Pettway

I'm using this to step down the 32 VDC from the solar panel to the 30 VDC Jackery 500 maximum. There are no instructions, so make sure you do some googling to understand what you're doing before you begin. Overall it does what I need and it's cheap, but it might not be the best solution for a variable voltage input like a solar panel. I only need it to dissipate about 75 watts, which it usually does well, but sometimes it fails and I have to turn it on and off to get power. Maybe the problem is with my setup, so I don't want to call the product about my possible problem. Which brings me to the on/off switch. Terrible location and you essentially need a small screwdriver to turn it back on when it's off. All in all good value for money and it does what you want it to do but maybe better for constant voltage applications.