Review on 🌡️ DROK Micro Digital Thermostat DC 12V: Temperature Controller Board with One-channel Relay and Waterproof Design by Kevin Folsom

Nice little thermostat. The funny thing is that the instructions are in Chinese. You can go to Youtube and search for the model number XH-W1209 to find a video with a little description of how it works. Since it's listed as a 12vdc thermostat and operates at around 12vdc, I wrongly assumed that power for what I'm controlling - the 12vdc fan - is supplied internally. No, that is not so. The board has 4 terminals labeled +12V, Gnd, KO and K1. You apply 12 VDC to the "+12 V" terminal and the ground wire to "ground", which supplies power to the device. You then use the KO and K1 terminals as breakers (switches) to control the power wire to the object you are controlling (motor, heater, fan, lights, etc.). The ground wire for your load (motor, etc.) completes the circuit. . If you are driving a 12V DC load, you can install a jumper between the "+12V" terminals and the "KO" terminal. This will supply your load with the required 12 VDC and when the required temperature is reached the thermostat will complete the circuit between terminals KO and K1. I wanted to wire this thermostat with (3) Li-Ion cells in series (min 9v - max 12.6v). The dealer wasn't sure if it would work in the lower end of that range so I'm trying to find out.