Since LiPOS are dangerous, you should be storing them at the Storage setting on a proper SkyRC balance charger.
As far as protection, it is a small PCB.
Do you plan on charging the battery under load or separate. If under load then the complete circuit is shown below and the forum thread with a LOT of info is at https://forum.arduino.cc/t/at-last-18650-charge-boost-module-with-load-sharing/1164462/5
If you want to use solar charging the circuit changes a bit with some solar specific components but I forget where the diagram is. If you need it let me know and I will ask the guy who knows.
