30A LED dimmer will not work for controlling electric throw?

The question concerns whether or not a LED dimmer, rated for 30A and 12-24VDC, can be used to control the heating of an electric throw?

The reason for the question: I have a 12VDC heated throw that I wanted to try controlling temperature since the voltage was fixed with no way to adjust. I bought a 30A 12-24 VDC LED dimmer thinking I could control the throw since the maximum VDC is 11.5 and no more than 4.5 A current, but within a short time, and to my great surprise, the dimmer became so hot I could hardly touch it and began smoking. I would have thought "LED" dimmers would be like other 12V dimmers and with the "30A" rating, there'd be no issues but I was wrong..

Two questions:

1) Why did the dimmer burn out?
2) If a "LED" heavy duty dimmer can't do the job, what type of dimmer could at 12VDC?

Thank you.

 

It was a dimmer I bought from Amazon, Chinese origin. Overrated perhaps, but that much overrated?? Inside the dimmer were
two HY1707 Mosfets, an LM358, a 78L05, a 555 timer, and support parts. I would have thought it would have easily handled the task, which is why I was inquiring whether or not LED dimmers were for LED only.
Yes, 12 VDC for the blanket. Normally plugged into the car cigarette lighter, I used a spare 12VDC @ 7 amp switching supply. No, the blanket was fixed so I had hoped to insert the dimmer inline.

 

5V from where? I was driving the dimmer with the 12V switching supply.

 

Normally, and after my experience, I would agree, but the mosfet has a very high current rating. Even with no heatsink on them (dual mosfet circuit), it still shouldn't have burned at the low amperage. I'm just wondering if I should be using a different type of dimmer in this application, or even a motor speed controller of some type?

 

Agree with, that I should be using a different type of dimmer? Yes, the throw is resistive, appears to use heating wire within.

 

According to the info, it does use PWM.

 

So far, just the 12V switching supply I have available. Would a 12V battery make a difference?

 

Thanks for all the suggestions here. Since the dimmer is now hard to trust after what happened, and since I want to run additional tests, what sort of a set up would be recommended since I don't want to stink up the room with the smoke smell again? I was thinking a couple of fast blow fuses and a smoke detector placed nearby for starters, but welcome other suggestions. Just to note that problems didn't start until after the system had been in operation for quite some time. Thanks.

 

I have an unused one here. Perhaps I will try and draw a schematic from the board, but it won't be for a few days. Just to note that I'm not very good at such a task so there might be errors. In a pinch, I could share circuit board images more quickly.