P60L Heatsink

Having bought 3 of the Surefire P60L's I've noticed lots of posts expressing concerns about the possible damage that the LED may sustain when used continuously in Nitrolon bezels.

Although Surefire hasn't specifically mentioned thermal degradation as the reason for them changing the Nitrolon bezels for aluminum ones on the G2L & G3L the majority of CPF members who've posted on the subject feel that is the real reason for doing so? Even 'Al' has posted that he thinks similarly.

Looking at the construction of the P60L it doesn't appear to be particularly well heatsinked. From an external examination it appears to only utilize the reflector for heatsinking? Having seen the pictures of the P61L in the 2008 Surefire catalog that too appears to utilize similar components for the body of the module?

Given that good heatsinking is a prerequisite to a LEDs performance and longevity and other manufacturers such as Malkoff and Wolf Eyes, to name but two, use brass in their modules to aid heatsinking, it seems strange that Surefire appear happy to forgo that measure?

Whilst I know that Surefire warranty their lamps & modules it is still disconcerting to think that the LED's may have considerably shorter lives due to this issue?

Doug

That's why the P60L doesn't run its emitter nearly as hard as those others and has circuitry that curtails output with increased temperature.

The P60L has a thermal sensor that reduces the output to prevent over-heating. SureFire obviously consider what thermal management systems the P60L does have to be sufficient for it to be used as is.

As for the P61L - this is an example (just like with the KL9 and UB2 etc etc) of the catalog not having the finalised product shown in it. This is because proto-types of these new products did not even exist at the time the catalog was designed and then printed. The UB2 and P61L were not even shown at SS2008.

Whilst I know typo's are common and Surefire hasn't yet brought the P61L's to market it appears from a statement made in their tactical catalog (page 77) that the P61L is also throttled back from the initial 200 lumens to 100 lumens by a temperature monitoring chip.

This being the case perhaps they should have gone with a better heatsink?

Before I get flamed this isn't an anti Surefire stance. Hell I've just bought 3 of the P60L modules so I do have faith in Surefire's technical ability. However, I feel that it is regrettable that third party manufacturers can bring to market a LED module which runs at a higher output for longer time without thermal degradation being an issue!:sigh:

Doug

dougie said:

Whilst I know typo's are common and Surefire hasn't yet brought the P61L's to market it appears from a statement made in their tactical catalog (page 77) that the P61L is also throttled back from the initial 200 lumens to 100 lumens by a temperature monitoring chip.

This being the case perhaps they should have gone with a better heatsink?

Before I get flamed this isn't an anti Surefire stance. Hell I've just bought 3 of the P60L modules so I do have faith in Surefire's technical ability. However, I feel that it is regrettable that third party manufacturers can bring to market a LED module which runs at a higher output for longer time without thermal degradation being an issue!:sigh:

Doug

Click to expand...

Doug,
Perhaps SureFire arrive at their ratings and at what they can achieve as a result of not just testing a sample fresh off the line but also after testing it throughout a reasonable lifespan of the product?

Perhaps the output performance achieved by LED products degrades not only in use, but also through use over time?

Perhaps aftermarket dropin makers are unconcerned or unaware of the degradation impacts of actually using their products in the same way SureFire knows its products are used? Perhaps they are responding to more of a fashion demand rather than a need to have the products continue to perform in 2 or three years+ of heavy use?

Put 20-30 of each drop-in through 50-100 battery cycles measuring the output performance of each one on the first and last run (assuming they all make it that it) and periodically in between.
Most people would agree that's quite a lot of work.
Perhaps this is one of the reasons why SureFire have not been rushing to put a "high output" LED dropin onto their market?

Something to think about?

Al

I think 15's has it right. I don't doubt that the SF dropins are the most reliable and highest quality units (with the possible exception of Gene's handmade pieces, but it's not fair to compare apples and oranges) available, and I think the specs they chose for them are pretty reasonable, all things considered. They're a good mix of what their customer base has been demanding, without any reliability compromises. Those wishing to get a bit more out of their LED modules may want to try:
1) Buy a 6P or 9P. More Aluminum means better heatsinking.
2) Put thermal compound on the contact surfaces between the module and head. Assuming you make sure not to interfere with electrical contact areas, this should help transfer heat to the aluminum head and body.

I have one of the original prototype Malkoff M60 dropins from a long while back, before they had thermal regulators in them, and the thermal compound helps it run longer before I start to see color shift from the SSC emitter.

Of course, the best solution is to buy one of SF's purpose-designed LED lights. I imagine that SF came up with the best design for the drop-ins based on the market, predicted use, cost/benefit, durability, etc... but they're still drop-ins and must adhere to the same laws of physics obeyed by all drop-ins regardless of manufacturer. The purpose-made LED lights shouldn't have this disadvantage as one of their design considerations and therefore are probably a better solution overall as compared to the P60 and P61 compatible alternatives.

Well if my P60L's get through 50-100 sets of batteries then they will have given me approximately 150-300 hours of use. I will be happy with that type of performance at a cost of £30 per module compared to a conventional incandescent bulb life of 30 hours. In reality I would hope for a longer lifespan from a LED but at my present rate of usage it would still take me 2-3 years to use 50 to 100 sets of batteries per light. In 2-3 years time who knows what new modules will be available?

Doug