I don’t know what the name of the thing I’m looking for so’ll try to decribe it.
I have battery operated heating pad that put out to much power.
Reducing power with a step down cable could be an option, but I think they all introduce conversion losses.
Recently I was measuring the power draw of USB heated clothing and noticed the power is always at 1.3A at the high setting.
At medium it’s on for 1 second and off for a second. At low it’s off 2 out of 3 seconds. It think that method may be quite energy efficient.
I found switches on AliExpress that do exactly what I want Page Not Found - Aliexpress.com
But I’m looking for a ready made solution. A cable/plug with USB in and out.
Any advise on that?