Winter heater

So I went to junk yard and picked up a couple carbon fiber seat heaters

These have the grid patern not the SIN pattern

Am I wrong to think these run 1-12 v so 1 2 or 3 cells in series should power these

Could be a nice heater for football or hunting

A bit more information needed. Is this a car seat heater, or a different type of heater? If it's a car seat, then 12V should be the operating voltage. Since it's a resistive load, then it should be able to handle a 4s voltage range (16.4V - 12.8V).
The temperature adjustment is probably adjusting the voltage to the elements. So by having it higher voltage, there'll be less amps, which means you can get away with less cells in parallel. You will need to find out the specs of the seat to narrow down any other details. Like, how many amps does it run on 12V. If it's 5A, then you want at least 5p. If it's 2A, then you can do 2p (depending on how long you want to run, as well)

Yes they are car seat heaters approx 12 in x 12in.
I will be testing with high drain drill batteries to see how hot they get and how long they last.

One nice thing about carbon fiber mesh is you can trim the heater and the remaining pad will still work as long as positive and negative are connected through the mesh/grid parallel paths

At least this is what I was told is reason not to get a heater that has one continuous wire.