my use-cases for 3.7v Li-ion batteries

• flashlights, so POWERFUL!! done!
• to charge cellphones in the event of a power outage done!
• TODO: explore if they can be used to jump-start a car's lead-acid battery [1]
  • background reading [1] [2] [3]
• a pack of 18650s that can be used to run any 12v cigarette-lighter device