My son is doing an Eagle project where he is creating a solar charged LED light set up using two 18650 cells in parallel. We are working to ensure they are safely protected. From the research we have done, a small BMS for the pair of cells and a fuse for each cell seem to be the way to go. We are thinking PTC's from reading, but will need a little help sizing them. The load is a 0.10 amp LED light string that he is powering.
What's the best way to size the PTC so we can give it try? Also, is there a better way to protect the cells? I can provide part numbers and circuit details if needed to help.