Lights

That's one thing bother me about the V1, there's no indication on whether the battery might die, it just turn off without any kind of warning,

^This is true, however you can always run it on full power, when that runs out just switch on again at half power which usually gets me another 30mins run time. You could even go to flash mode and i would guess you'd get an hour or more. I guess that's my way of a 'warning' and gets me home safely without needing to carry spares :)