I prefer to keep my cellphone battery for making calls. I EDC either a Fenix E01 or an E12. The E12 is a very good light which is useful in a variety of situations. For me the E01 is more an emergency light the primary purpose being to get to a bigger light. The E01 is in a CountyComm Zipper Key Pouch -- very handy for carrying small EDC items. I prefer a small pouch to carrying stuff on my keyring.