HiLetgo 2pcs W1209 with Case 12V DC Digital Temperature Controller Board Micro Digital Thermostat -50-110°C Electronic Temperature Temp Control Module Switch with 10A One-Channel Relay and Waterproof

I give it 5 stars because I'm very satisfied with the product. It's precise and well-conceived. It's got a few rough edges, though. (I decided not to deduct a star, because the everything else is so good.)1. Very clever and attractive little plastic case. However, it requires assembly, which takes a bit of time. It is made of 6 precision-cut panels with protective film that you need to peel off. They insert together with tabs. Getting all the tabs in the holes is a fiddly process. If you want the case to be completely flat for mounting, you might want to remove a bit of the tab material before assembling, as the tabs stick out ver slightly (fraction of a mm) on the opposite sides of the holes.2. Some of the leads on the bottom of the board are a bit too long for the spacers provided, so you will need to trim them before mounting it onto the bottom panel of the case.3. I don't like the screw terminals. It's hard to insert wires into them. I have a rather stiff 18AWG wire that I used, just because I could push it into the terminal. Forget using any finely stranded wire, unless you use a (small) ferrule.4. The two boards I received disagree by 0.8 deg C. It's not a deal-breaker by any means.5. Setting the "on" temperature is very intuitive, but there are no instructions. Press (do not hold) the set button, and then set the temp with the +/- buttons. When you hold the set button, you end up in some mode to select different programs, without any idea what those are. (I think they set different hysteresis values.)6. The relay is pitched as 20A. However, that's the rating for 15VDC. The 120VAC rating is 10A. The 240VAC ratting is 5A.Other than that, the board is very snappy and precise, programmable to 0.1 degC increments. The temperature probes respond quickly.

I have a home made cabinet for my CNC router. There is a compartment for the computer, but it doesn't have much air circulation. The other day I noticed the temperature was quite high in the cabinet and possibly a contributing factor for a recent hard drive failure.I wanted to add a fan to circulate air, but since the computer goes in to sleep mode and doesn't generate much heat when it's not being used, I didn't want something that ran all the time. With this gizmo and a 12V fan, I was able to set it up so the fan only runs when the temperature in the cabinet exceeds a certain amount. So far it seems to be working great. I have it set to come on at 32C and go off at 30C, and it's been been right in that range each time I've noticed the fan running.Set up was easy. I already had a 12V supply available in the cabinet, so all I had to do was hook up the power, insert the K0 and K1 ports inline with the positive lead of the 12V going to the fan, and drop the sensor in the cabinet. As I recall the default settings were what I needed, except maybe changing the temperature range.I opted for the case and that was worth the extra 60 cents. I could have laser cut my own, but it probably would have cost me 60 cents worth of material and certainly more than that in time. The only complaint about the case is that is doesn't provide any holes to mount it to anything unless you want to use the same holes used to hold the case together. No big deal - some double sided foam tape got the job done.Definitely worth it for less than $5 each.

This worked perfectly for what I needed. I used it to power an auxiliary fan to help keep a grid tie inverter cool. Wiring was a bit confusing but I ended up figuring it out.There are 4 spaces for wires. Going from left to right I wired mine as follows:1. Positive to fan2. Jumper wire to space 3 (I used a prong connector instead.)3. Positive from battery4. Negative from battery and negative from fan.Turns on and off as it should within reasonable accuracy. It is in Celsius so get a conversion printed out.Assembly is required but not difficult. Make sure not to over tighten anything to keep from breaking the terminals. I finger tightened all screws.

I use these for some 12v 120x120 brushless computer fans I installed in my chicken coop. Turns on the fans you can set the temp and when for it to come on you can choose 1°- 3° on/off as well. Only Draw back i had was it's only in reads in C not F but after learning the difference it's was not a deal breaker for me.

I have installed a pair of solar charge controllers in my cargo trailer / camper conversion. In the bright sunlight, the controllers get very warm. I know that the controllers are designed to run at these temperatures but I have surplus computer fans just sitting around. I decided to use the controllers to monitor the temperature on the heat sinks of the controllers and turn on cooling fans when they got too hot. They are working like a dream.P.S. the little acrylic housings were a pain to assemble, but for the price, they couldn’t be beat.

Only received 1 case, 2 screws for the 1 case, and 1 probe. Assembly is fairly straight forward, no instruction for assembly or set up.