Why does the HM50R V2 drop from higher output levels?Updated 2 years ago

There are two reasons for this:

1. Overheat protection - When the lamp reaches 140° F (60° C) the light will reduce the brightness output to allow the light to cool down. Once the light has been reduced below that threshold you will be able to select the higher out levels again.
2. Low voltage warning - If the batteries are no longer able to safely support the higher output levels, the lamp will drop down and will not allow the light to be pushed back up into those output levels in the interest of protecting the batteries from undue strain.

You can tell which of these two reasons is the cause of your step-down by checking the battery-level indicator.