Another vote for exposure, I have a Mk12 joystick that is fantastic, a friend still uses his ancient joystick and is happy with it.
For my barlight I use a Lezyne 1500xxl road light which works really well, I can ride my local trails at full daytime pace after dark.
Both lights have more than enough battery life usually showing over 50% remaining after a 3-4 hour ride if your sensible with the power setting using low for climbing and high for the technical bits