Crank flashlight in 0.8.2b seems to only hold a charge when there's a battery in inventory.

Steps to replicate:

1. Drop all batteries from inventory
2. LMB on Crank Flashlight to put it into inventory
3. Hold Crank Flashlight
4. Hold Left Alt + spam RMB to chaaaaaarge
5. Hit RMB without Alt to re-equip it
6. Hit F to switch on flashlight but eek it's still dark
7. Now equip a battery
8. Go through steps 2-5 again (note that Crank Flashlight charge is 0.0 when you equip it, rude)
9. Hit F to switch on flashlight yay it works now