So, I'm a total amateur, my sum total electrical engineering experience is stuff my grandpa explained to me when I was 6 and playing with Snap Circuits.
I'm trying to build an electric heater in to my jacket: I purchased this battery:
and this heating element: https://www.amazon.com/gp/product/B00ZP3XCS4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
The element is a silicone heat pad designed for 3D printer beds; it's rated for 150 watts @ 12 volts. It was the cheapest thing that seemed like it would do the job in my price range. The battery is a lithium-ion pack that's supposed to output 72 watts at 12 volts. They say it's supposed to be able to handle a 6 amp load continuously but I'm aware battery manufacturers always lie. An electric blanket is supposed to draw around 2 to 3A anyway so that should still be enough in theory to get the job done.
Now I realize these numbers don't match up, but I figured the heater would just... not be able to pull more amps than the battery will put out. I don't want it going up to its design temperature anyway (there's an electronic thermostat involved here too).
The thing is, I've tried connecting the heating pad directly to the battery and nothing happens. Even leaving it there for half an hour, the pad is still cold to the touch.
Do you think it's more likely that there's some overload protection circuit on the battery pack that's cutting off the power, or is it more probable that something's just broken?
I've checked the pad with my multimeter and it gives me an ohm reading, so presumably there isn't a broken connection inside the thing. Interestingly, checking the output of the battery gives 8 volts (at half charge) to 10 (fresh off the charger,) and whether the heater is connected or not doesn't seem to have any effect on that. The multimeter also gives 10 volts checking the charger itself though, so maybe it's just broken. It's pretty old...