This sort of approach is all over the interwebs so I won't belabor it.

I wanted the data collector and reporter to be solar powered so I grabbed a DC/DC converter and a charger from Aliexpress. Both had USB connectors so a stubby little USB cable made it a trivial task.

But trivial isn't fun and I didn't want to sacrifice a cable so i deconstructed the USB on the converter, desoldered the pins and soldered connecting wires to the charger.

A happy little fellow with a great big USB connector.

It's the top and bottom pins of that row of four I want to expose.

And so I did. Tearing stuff apart is my strongest hacker skill.

A little perf board, a little hot melt glue, a couple connectors and here's the charger circuit.

It's the top chunk of perf board in this picture, connected to the LiPo and ready to be stuffed into its weatherproof enclosure /sandwich box and connected to the solar panel.