I honestly don’t know. The battery in an iPhone is bigger than 4400mah (typically 4-5000 mah in a smartphone) but I expect the voltage is lower in the phone than the 12v in the jacket. I was just suggesting the battery pack might be able to extend the time the jacket stays warm. There are plenty of battery powered heated jackets etc out there that I’m sure would give you an idea if the tech works in general. Or get a traditional plug in jacket and a small lithium iron motorcycle battery from Shorai.
Or get a traditional plug in jacket and a small lithium iron motorcycle battery from Shorai. That's a really good idea, I might look into that. There's also a Firstgear jacket that can be wired to bike or run on battery: https://fortnine.ca/en/firstgear-12v-battery-heated-jacket-liner-kit More money, of course, but it might offer the most flexibility.
Try https://firedupx.com/ I golf with mine on. It's far infrared technology. Optional power adapter also
Looks great, but I'm going to go with a full jacket this time. I have a heated vest but I still get cold and the jacket should get me over the hump by heating my arms and neck too.
