Princeton Tec Apex LED Headlamp

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Postby NZcaver » Feb 7, 2007 4:09 am

Ladies and Gentlemen - welcome to this issue of the Apex testing and torture report! :hairpull: :devil:


I've just been experimenting with this waterproofing issue, using my caving Apex (black model) and a second Apex (orange model) as a comparison. The black Apex is almost a year old, has been caving, and is modified. The orange Apex is about 9 months old, and had not been abused, modified, or even unscrewed (before I began this little experiment).

Here are the modifications I have done to the black Apex. I filed the 3 screws slightly shorter (about 0.5mm) as discussed recently in this thread. I also lightly lubed the light head and battery pack seals with clear o-ring grease. I then super-glued the battery cable into the housings at each end. This was because the outer black insulation was starting to pull out at the battery housing end, leaving the blue and black wires inside visible.

Note the standard for waterproofing that applies to the Apex is Princeton Tec's Level 2 Intermediate Rating (equivalent to IPX7). In English, it should provide waterproof integrity down to 1m underwater for up to 30 minutes.

I started by removing the elastic headbands from each lamp, turning them on, and dumping them in a small bucket of water (they can’t swim, so they just sunk to the bottom). I left them in tap water for 30 minutes at room temperature (about mid-70's) before removing the headlamps and towel-drying them. There was no evidence of moisture inside either headlamp.

Image

Next I started playing with temperature/condensation changes. I placed the headlamps in the refrigerator for about 10 hours. When I removed them, there was a light moisture coating on the outside of each (which was to be expected). This promptly evaporated within a few minutes at room temperature. I then placed them in direct sunlight for about 30 minutes. Again, there was no indication of moisture/condensation inside.

For the final test, I placed the small bucket of water in the refrigerator and allowed it to cool. I then turned the headlamps on and dropped them in the water for about 30 minutes. Upon removing them from the water and bringing them back up to room temperature, the thin moisture coating on the outside reappeared. Again, I turn the headlamps off and placed them in direct sunlight for about 30 minutes. This time there was a noticeable result!

Image

Moisture was visible inside the lens of each headlamp. In the black (modified) Apex, there was slight fogging of about 50% of the outer (5mm LED) lenses. The central 3W lens was clear. In the orange (unmodified) Apex, there was the same fogging but also some more significant moisture in the outer lenses. I shook both headlamps vigorously to see if there was any water moving around. The black Apex stayed slightly fogged, but the orange one clearly showed liquid inside. Specifically, what appeared to be small drops of water had formed on the tips of the 4 LEDs. There was also a thin layer of liquid right inside the face of the 3W lens - between the layers of plastic.

Most disturbing was that although the black headlamp continued to function fine, the orange one had issues. I could turn it on, but it would repeatedly shut off again after anything from a couple of seconds to a minute later. Occasionally it would do a funky flashing thing, alternating between 3W and the 4 LEDs for a few seconds and even switching itself back on a few times. I swapped out the batteries for newly-charged ones, and got the same result - the moisture was clearly causing havoc with the switch/electronics.

I opened the battery compartments. Both headlamps had a few small water drops inside, but not enough to do any damage. Time for surgery - next I opened the light heads so they could dry out. Other than the lens fog, the black Apex was dry. As soon as I opened the seal on the orange Apex, between 1/8 and 1/4 teaspoon of water poured out! I shook the rest out, and periodically tested the operation of the light with the headlamp open. The switching slowly got less sporadic and eventually returned to normal.

Once the orange Apex was dry, I noticed the circuit board had a film on it. It’s probably the high mineral content in the water here. An alcohol prep pad and a cotton swab seemed to take care of it. If I have any ongoing issues, at least there’s a lifetime guarantee on the Apex from both the manufacturer and the retailer.


Conclusion - if you're going to be caving, particularly in cold and/or wet caves, you really should plan to modify/service your Apex to improve reliability. I guess I have another Apex I need to modify now. :wink:
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Postby bigalpha » Feb 7, 2007 11:02 am

Wow, awesome testing. It seem that that the warm water doesn't have any effect on anything; but the culprit is the cold water. That would definitely jibe with cave usage. I wonder if the cold is shrinking the rubber o-ring or something?
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Postby fuzzy-hair-man » Feb 7, 2007 7:22 pm

NZcaver wrote::
Most disturbing was that although the black headlamp continued to function fine, the orange one had issues. I could turn it on, but it would repeatedly shut off again after anything from a couple of seconds to a minute later. Occasionally it would do a funky flashing thing, alternating between 3W and the 4 LEDs for a few seconds and even switching itself back on a few times. I swapped out the batteries for newly-charged ones, and got the same result - the moisture was clearly causing havoc with the switch/electronics.
:


Thanks for the testing NZCaver :kewl:

:exactly: I had these symptoms on one of the Apexes I returned. I'm glad it wasn't all in my mind :nuts:
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Postby bigalpha » Feb 7, 2007 7:34 pm

Someone had posted about replacing the reflector in the Apex -- has anyone tried this yet?
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Postby fuzzy-hair-man » Feb 7, 2007 7:35 pm

bigalpha wrote:Wow, awesome testing. It seem that that the warm water doesn't have any effect on anything; but the culprit is the cold water. That would definitely jibe with cave usage. I wonder if the cold is shrinking the rubber o-ring or something?


A member of our caving club had the theory below.

fuzzy-hair-man wrote:Are you saying that your Apex doesn't let water in ? how cold is the water in your caves? the reason I ask is one of our club members suggested that it might be that a sudden immersion cools the heatsink and inside of the Apex very quickly, as we all know hot air expands, cold air contracts so if it cools suddenly there is suddenly a suction of the air inside the Apex this is right when it is underwater or covered in water so it sucks the water in, making it that much harder to make it waterproof.

I did have thoughts that if I cooled the heatsink (by dipping only it in water) then went and did the wet section I'd be cooling the light down significantly before it gets immersed..... :question: I haven't tried that yet though....


Hey NZCaver you don't want to humour me by trying the 2nd paragraph, ie dunking only the heatsink first and then the headlight? not that it will confirm much (I guess we know the temperature difference is the problem) but it might prove or dis-prove it as a way of minimizing the amount of water that gets into your Apex. :question:
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Postby NZcaver » Feb 7, 2007 8:23 pm

fuzzy-hair-man wrote:Hey NZCaver you don't want to humour me by trying the 2nd paragraph, ie dunking only the heatsink first and then the headlight? not that it will confirm much (I guess we know the temperature difference is the problem) but it might prove or dis-prove it as a way of minimizing the amount of water that gets into your Apex. :question:

Well, this works on the premise that your Apex has already been running for a while and the heatsink is warm. Sure it's common in a cave to have the headlamp on well before hitting the water, but unless you are running the 3W beam a lot - how warm would the heatsink get just on the 4 LEDs? I'm thinking not too much, but then it's not something I've tested yet.

Regarding my recent testing - I switched the headlamps on (4 LED high mode) immediately before dunking them each time. The heatsinks would have been at room temperature (mid 70's F/mid 20's C) before being immersed in the 40 F (5 C) water. Just for fun I toggled them both to 3W and back again underwater, but only briefly.

I have not "modified" the orange Apex yet. It's still sitting in pieces at my feet. I could put it back together as-is, and try refrigerating the Apex (dry) for an hour or so before putting it in water (still in the refrigerator) for 30 minutes. Maybe I'll do that in the next day or so.

As a footnote, the reason why I placed the headlamps out in the warm sun immediately after each round of testing was this. One time my black Apex actually fogged for real after a caving trip. The cave was cold (low 40's F/5 C) and damp, but not immersion wet. After couple of hours in the cave (at 3000 feet/1000m), we made the 1 hour plus hike back to the vehicles in about 80 F (high 20's C) temperatures. It wasn't until hours later at home (near sea level) that while changing the batteries, I discovered minor fogging in the light head.
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Postby Biggimo1 » Feb 8, 2007 1:29 am

bigalpha wrote:Someone had posted about replacing the reflector in the Apex -- has anyone tried this yet?


I replaced the reflector in my PT EOS. This worked out great and made it more of a useful caving light. I don't own an Apex, but if I did, I would change that optic. I would put in a 17 or 20 mm IMS reflector. I used a 17 in my EOS, but I think the Apex's optic is a little bigger.

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Postby Biggimo1 » Feb 8, 2007 1:50 am

I just read about it. 17mm reflector is too small and 20mm is a little too big. they are made of plastic though and can be shaved down to fit.

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Postby fuzzy-hair-man » Feb 8, 2007 2:46 am

CandlePowerForums have been discussing it here:

http://www.candlepowerforums.com/vb/showthread.php?t=131044

At the bottom it says:
I took mine apart the other night...

The 20mm IMS reflector looked to be a good diameter, but its a bit too tall.
Might be worth cutting one down to fit.

I plopped a 17mm IMS in it, which fits, but is a much smaller diameter than the optic.
I actually got a goof bit less Lux out of it though,
yes, it was a smoother beam, with some spill to it,
but I didnt like the drop in lux.
The 5mm leds do a nice job of flood, so I left it stock.
I just wish you could turn on both sets of leds at once.

~John


There is also a picture of an Apex with the 17mm IMS reflector
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Postby NZcaver » Feb 8, 2007 4:41 am

Biggimo1 wrote:
bigalpha wrote:Someone had posted about replacing the reflector in the Apex -- has anyone tried this yet?


I replaced the reflector in my PT EOS. This worked out great and made it more of a useful caving light. I don't own an Apex, but if I did, I would change that optic. I would put in a 17 or 20 mm IMS reflector. I used a 17 in my EOS, but I think the Apex's optic is a little bigger.

Thanks for posting the info on the optic. :grin:

Judging by Fuzzy's previous post that quotes candlepower forums, the 17mm reflector is a waste of time because it reduces the light output and the 20mm will need some further modification to fit the Apex. Of course by doing this, you may lose some of the intensity of the bright spot provided by the original focused optic. Or not??

I read about that EOS conversion a while ago, and considered doing it to my one. For caving, it would be nice to have a broader beam if you use an EOS as your main or back-up headlamp (which is why you modified your own reflector, I assume?) As an occasional-use spotting light, the EOS is fairly effective just as it comes. With it's tight beam and some side-spill, it's also great to strap to the front of your bike for short night rides (which I've actually done, while wearing a second headlamp on my head). I soon found the real downside with the EOS, in my opinion, is the relatively short battery life when used at any reasonable intensity - and that won't change by modifying the optics.

Then when the Apex first came out, people were buying them primarily for the blazing 3 watt spot beam. Almost immediately, the majority of users (cavers and non-cavers alike) found a major benefit of the Apex is the 4 LED mode, which gives a bright, broad beam that's perfect for 90% of what a headlamp is used for - namely walking/climbing/moving in the dark. Plus in that mode, you get a lot more battery life.

So after all that - will replacing the optic with a basic reflector give the Apex a brighter spot? If so, it might be worth doing. But if you just want to get a broader beam, why not just push the button and switch it to the other mode? :?
Last edited by NZcaver on Feb 9, 2007 1:43 am, edited 1 time in total.
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Postby bigalpha » Feb 8, 2007 11:33 am

I don't think you should ask me questions that I'm not totally prepared to answer!

I was just wondering if anyone had replaced the reflector, and what kind of difference it made. I thought perhaps changing the reflector would make it brighter/more efficient.

So, shortening the screws, then tightening them down tight helps solve the water problem?
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Postby fuzzy-hair-man » Feb 8, 2007 6:45 pm

bigalpha wrote:I was just wondering if anyone had replaced the reflector, and what kind of difference it made. I thought perhaps changing the reflector would make it brighter/more efficient.


From what I found whilst looking for the above page, reflectors are supposed to be more efficent than optics. The Apex uses optics, so replacing these may give more light.

Another candlepower topic which has some beam shots of the IMS 17 and IMS 20 reflectors for anyone interested:
http://candlepowerforums.com/vb/showthread.php?t=81679&page=1&pp=30
These reflectors are in a MiniMag so I don't know what they would look like in say the Apex where you can't focus the beam.
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Postby Biggimo1 » Feb 8, 2007 11:54 pm

You have to see it to beleive it. The reflectors better focus the the center of the beam , making it brighter and whiter, but also gives it more useable side spill. You lose alot of light in the optics.

The 17mm would not be a waste, you would just have to use some silicone to hold down the reflector.

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Postby NZcaver » Feb 9, 2007 1:21 am

Biggimo1 wrote:You have to see it to beleive it. The reflectors better focus the the center of the beam , making it brighter and whiter, but also gives it more useable side spill. You lose alot of light in the optics.

The 17mm would not be a waste, you would just have to use some silicone to hold down the reflector.

You're right - I probably would have to see it to believe it. I was basing that comment on the information from candlepowerforums - these guys are usually pretty thorough when they test and modify things, but I guess they could be wrong. And so could I. :?

Want to get an Apex for yourself and try it out? :wink: Be sure to post photos... :grin:
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Postby Stelios Zacharias » Feb 9, 2007 3:36 pm

NZcaver wrote:Ladies and Gentlemen - welcome to this issue of the Apex testing and torture report! :hairpull: :devil:


Most disturbing was that although the black headlamp continued to function fine, the orange one had issues. I could turn it on, but it would repeatedly shut off again after anything from a couple of seconds to a minute later. Occasionally it would do a funky flashing thing, alternating between 3W and the 4 LEDs for a few seconds and even switching itself back on a few times. I swapped out the batteries for newly-charged ones, and got the same result - the moisture was clearly causing havoc with the switch/electronics.


I would just like to confirm for the record that this is the exact behaviour I noticed when I wrote about my apex playing up- only it happened without immersion but in a rain of drips over the course of 8-10 hours. The playing up was on rope with about 300ft of an 800ft pitch left to go. I came out with my tikka in the end :shock:
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