My main idea was to make a modular system that can be used with different clothes. I made two identical heating panels that can be combined into a single vest or attach to any outfit. Each panel has 2 meters of carbon heated tape. Chose the maximum width of the tape to provide a very even heating. Size panels 34 x 42 cm, since it is better suited for the size of my clothing.
In each panels tape connected in parallel 2x1m and has an independent power button.. It takes about 3A under 12V (36W) for each one or 72W together.
You can sew wire to carbon tape to make a good and flexible connection. The contact place shouldn't be hotter than the tape itself. If not you must increase the contact area. Sewed contact very flexible.
Contacts may be sewed by sewing machine or just wraped with a wire.
But as you can see sewed contact is colder than the tape itself (left contact).
Wraped contact (on the right) is more hotter than tape.
On each panel sewn 4 pieces of Velcro . Now I can combine them into a single heated vest . A bit like a bulletproof vest. It's very soft and thin.
Due to Velcro this vest will be comfortable to wear for a big man or a small woman.
Each panel can be used independently with any clothes.
On the inner surface of conventional jackets I sewed 4 pieces of Velcro.
Now I can at any time fix the heating panel on a jacket and make it heated.