I’m working on a project that requires a small battery. Given the size of my board is small I decided to use a 3.7V battery I got off Digikey that is using a 2 pin JST connector. The two major things I wish I knew prior to using this battery is as follows. Pin1 for these battery’s is ground (This can be found in the battery datasheet), I had assumed that Pin1 would be the positive side of the battery so this was a bit of a headache. Second, These are quite painful to install and can destroy your board if done incorrectly. If you use these connectors I would recommend that you either order extra boards to practice or get a fine tip on your soldering iron to install these.