TP4056 Type-C USB 5V 1A 18650 Lithium Battery Charger Module Charging Board TC4056A with Dual Protection Functions(Pack of 12)

I personally use one of these on one of my solar nodes running on an Xiao https://www.amazon.com/dp/B08F7QSLN7 Solar to the +/- pads next to the USB portBattery to the B +/-Battery pads on the Xiao to the Out +/- This board also has over discharge protection so if you use those Out +/- pads it will cut power to the Xiao if you go some time without enough sun to charge and will restore output once the battery is charged above a safe point. For solar you're going to need 5-6v in on those pads next to the USB port If you have a small like 3v panel it won't have enough voltage to charge the battery there is no boost converter on this board. I use one of these for my solar client_base node https://www.amazon.com/dp/B0CFYHFJ5S Panel outputs about 6v no load. I gutted out all the electronics for the light and have it hooked up as described above. With the 2 18650s it comes with I never see the charge less than about 90% The hole the light's wire passes though is almost exactly SMA sized for the antenna, you're just going to need to make the hole ever so slightly larger. You can also use one of these slightly smaller lights. https://www.amazon.com/dp/B0FC5RMCST I had a remote solar node built out of one of these before it was removed/stolen. It has a single 18650 in it. When it was removed/stolen I have no idea where it ended up but I was able to see that the voltage was dropping, so it was somewhere without sun and it ran for about 1 week off that single 18650 till I couldn't ping it any longer.