Comment by solyin

3 hours ago

I get what you're saying, but there are some hand warmers that just charge off of USB 5V.

Right it works if it's designed for it. But hooking up a 5V source to a stove element isn't going to cause much heat.

  • V=IR applies. I've seen 900 watt heaters running on just 3 volts. You need big wires and low resistance to pull it off but it works