Could you test the lights using the steps below? They might get them working immediately.
1. Unscrew the tail cap. The factory usually includes a white insulating disc between the battery and the tail cap. This disc must be removed before charging or using the flashlight.
2. Inspect the threads and ensure there is only one O-ring seated properly at the base. A misplaced O-ring can prevent the cap from tightening correctly.
3. Verify that the battery is installed with its positive button head towards the front of the flashlight.
4. Fully tighten the battery cap. Once you feel resistance at the end, rotate the cap back and forth a few times and give it a firm twist. A loose battery cap is a common cause of a malfunctioning light.
5. Press the protruded power button when pointing the light at your palm. Then tap the paddle button next to it to adjust the brightness. The dimmest setting might be hard to notice in a bright room.
In short, ensure the white insulating disc is removed and the tail cap is fully tightened. Does the flashlight work properly now? We look forward to your updates.