Almost all Reelight bike lights work without batteries, except Reelight GO and UGO. All of the lights, however, work in all types of weather. Your choice should be made dependent on where you intend to use the lights. If you need to be seen on small, semi-obscure roads, CIO, AMS Light and CPH Light are very suitable. If you also need to see in the dark, or NOVA or RL700 series is an excellent choice.