Cable to reduce power output

EDC Gear for Flashlight Carriers USB Power Devices
1

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?

2

Looked, nuttin’.

If you don’t want to cut into the existing cable, you can get a usb extension cable (m/f) and cut into that. One splice, one snip, that’s it.

3

Are you looking for something like this.
https://www.ebay.com/itm/15W-Adjustable-Voltage-USB-Power-Supply-Module-DC-5V-to-1V-12V-24V
By reducing the voltage to the heater it should lower the current unless the heater is using a boost circuit.
Have you looked to see if the heater has some kind of current limiting circuit or was it just relying on low current alkaline batteries?

4

Put a USB hub inbetween. This reduces current to 0.5A (USB 2.0) or 0.9A (USB 3.0).