Using an 18650 battery with positive and negative on the same end
If you've stumbled across an 18650 battery with positive and negative on the same end, you probably realized pretty quickly that it's not your average lithium-ion cell. Most of us are used to the standard "AA-style" layout where the bump is positive and the flat bottom is negative, but these dual-terminal batteries turn that logic on its head. They look a bit weird, they're often more expensive, and if you try to stick a regular battery into a device designed for these, it simply won't turn on. ...