Got my PT Apex a month ago and decided to test its water resistance. After surfing the forums to find out the possible problem areas I pulled it apart to look at the electronics and a possible upgrade of the led from 3 watt to 5 watt. Reassembling, I checked that the 3 screws did not bottom out in their respective holes. Insufficient clamping force is the main reason for water ingress in the headpiece.
Now for the test.
I ran the Apex on high beam for 1 hour to get the air inside the headpiece and battery case nice and warm. Then submerged PT Apex in cold water for 3 hours. If water is going to enter the Apex, it will be as the warm air inside the headpiece and battery case cools and contracts.
Dismantled and found tiny drops of water on the batteries inside the battery case and [b:3k9f4gem]NONE inside the headpiece[/b:3k9f4gem]. I accidentally dropped the PT Apex on the floor and therefore disturbed the location of the water inside the battery case. Iâ€™m guessing that the water entered the battery case via the clamping screw and not the rubber O-ring.
” title=”Very Happy” /> Overall the PT Apex appears to be a great caving headlamp. The little bit of water that entered the battery case should cause no problems as long as storage is with the battery case open and/or batteries removed. However, nothing will beat real world testing like one of the wet caves at Buchan involving sumps and mud to truly test the Apexâ€™s reliability.
The following website http://radiolocation.tripod.com/ApexHeadlamp.html has a good technical review of the PT Apex.