My nocturnal rides are pre-dawn - and the longest I plan to be out before sunrise is 2 hrs. Mainly this time of year and early Spring. As soon as it gets frigid it's harder to ride @ those times. But come March I start needing to get out early again. My issue with the Solo MV isn't the run time - 2 hrs. is fine - it's the brightness. But the cars DO see you with that solo MV. It's just not quite adequate for lighting the roadway up @ 20+ mph.