EA8, you gotta really love AAs

[xevious]

Any actual tests I've seen with these lights (EA4 and EA8) show that they have no problem with heat dissipation. My EA8W gets plenty warm after running on turbo for a few minutes. I can appreciate that they chose not to add any unnecessary weight, the light is heavy enough as it is (and well-balanced).

There's one thing about heat you can feel versus the actual temperature inside the light. What concerns me is that if there's insufficient heat dissipation, then the electronics will be stressed much more, shortening their lifespan. What would really help to know is what the average temperature inside is when running on high for long periods...

Either the innards are being forced to absorb more heat than they should, or the emitter/driver combination is engineered in such a way that heat generation has been significantly reduced. But if the latter was the case, wouldn't NiteCore be boasting about this rather than slathering on so much Loctite to try keeping casual people from examining the inner construction? (I don't buy it was done to foil the competition from examining the internal design, because any competent professional can take apart a light no matter how much Loctite you use).

 

[bluemax_1]

Yep, I have to agree, after looking at that thread, the thermal path in the EA8 is certainly not the best. I wonder if anyone's taken apart a TK41 and how the 2 compare since they're very comparable (8xAA, similar size, output and lux ballpark)?


Max

P.S. Found some pics of Fenix's lights
http://www.candlepowerforums.com/vb...e-Successfully-Mod-a-Fenix-TK41-or-TK60/page2
much more substantial. If the pics of the LD20 on the previous page in this link are any indication of Fenix construction, the star is sitting on an aluminum plate that is in direct contact with the body. Much better thermal pathway.

 

[Slazmo]

how hard is it to crack the bezel on the EA8 - I wonder if it would be similar to the EA4. I want to pull mine apart and get this piece of plastic that is wedged beneath it and against the lense... Nitecore just want the torch back but I want to get it sorted out rather than paying for postage around the world!

Is there any good tools that anyone could recommend to get a good purchase on the bezel in those inner nodes without slipping and scratching it to death or smashing the lense itself?

 

[pjandyho]

I half suspected the heat sinking wasn't good. My wife was playing with my EA8W on max for about 10 mins and the light doesn't even feel hot at all, just pretty warm.

 

[Curious_character]

Well, since we're talking about the merits of AA here in addition to the EA8, I was rather dismayed to find a peculiar performance issue last night.

I took 7 lights with me into the darkness to test out long distance illumination. The EA4 was better than all of the others I own (not surprising, given the next highest is 320 lumens). I did not drive the light for more than about 6-8 minutes on nearly full Eneloops, when I noticed the button indicator was flashing rapidly. And, it wouldn't let me change beam intensity. It had dropped back from turbo into high mode, but I couldn't get the light down to low. Really weird. And from what I understand, the UI is identical between the EA4 and EA8.

According to Nitecore "When the light is on, the power indicator will blink consistently when power levels are low." I locked out the light to let it report on the voltage... and it came up with 3.6v. It was 4.8v when I left the house. When I unlocked the light, I was able to change modes again without issue.

Anyway, when I woke up this morning, I checked the voltage and it read 4.7v.

So that's another thing I'm wondering about... with NiMh vs. lithium. Is there much of a difference in how they handle and recover from loads?

An important difference between lithium and NiMH cells is that the voltage of a lithium cell gives you some idea of how much charge or energy is remaining. That's not the case with NiMH, except when they're newly charged or completely discharged. Don't confuse voltage with energy. If a cell reads 1.2 volts with no load, it could have something like 50% of its full energy left, or it could be very nearly discharged. If you discharge it down to 1.0 volt or so then remove the load, it'll soon bounce back up to 1.2 volt or more, but there won't be any substantial amount of energy left in it -- it's dead until you recharge it. Your battery was probably nearly dead when you started, and was completely dead after a few minutes of heavy drain.

c_c

 

[xevious]

An important difference between lithium and NiMH cells is that the voltage of a lithium cell gives you some idea of how much charge or energy is remaining. That's not the case with NiMH, except when they're newly charged or completely discharged. Don't confuse voltage with energy. If a cell reads 1.2 volts with no load, it could have something like 50% of its full energy left, or it could be very nearly discharged. If you discharge it down to 1.0 volt or so then remove the load, it'll soon bounce back up to 1.2 volt or more, but there won't be any substantial amount of energy left in it -- it's dead until you recharge it. Your battery was probably nearly dead when you started, and was completely dead after a few minutes of heavy drain.

Thanks for the info, c_c. These were Eneloops running off of their original charge from the package (they claim they're shipped fully charged). So, it may very well be that the charge was already diminished, as I hadn't really put them through much use at all before I started seeing this weird behavior of the EA4. Anyway, gave them a solid charge overnight so I'll be testing out the light this weekend and see how it goes.

I half suspected the heat sinking wasn't good. My wife was playing with my EA8W on max for about 10 mins and the light doesn't even feel hot at all, just pretty warm.

After that I wonder if you opened up the light, if you'd find that the back of the head was very warm or even hot. If the inside remains fairly lukewarm, then there must be some really ingenious temperature regulation going on with the driver. Otherwise, where is the heat going? Do you feel much heat being expelled out the front when on high?

 

[pjandyho]

After that I wonder if you opened up the light, if you'd find that the back of the head was very warm or even hot. If the inside remains fairly lukewarm, then there must be some really ingenious temperature regulation going on with the driver. Otherwise, where is the heat going? Do you feel much heat being expelled out the front when on high?

No. It did not occur to me at first although I should have noticed it since I have been playing with lights for more than a decade. Guess my mind was too caught up with whether she was more interested with the EA8W or the TM26. She played with both and passed the TM26 back to me. The whole time she was proclaiming how much she preferred the neutral tint of the EA8W as compared to the cool white of the TM26. I love this girl!

 

[melty]

Either the innards are being forced to absorb more heat than they should, or the emitter/driver combination is engineered in such a way that heat generation has been significantly reduced. But if the latter was the case, wouldn't NiteCore be boasting about this rather than slathering on so much Loctite to try keeping casual people from examining the inner construction? (I don't buy it was done to foil the competition from examining the internal design, because any competent professional can take apart a light no matter how much Loctite you use).

There could be any number of reasons to use glue. Here's a thread about it. Why does it have to be a conspiracy?

After that I wonder if you opened up the light, if you'd find that the back of the head was very warm or even hot. If the inside remains fairly lukewarm, then there must be some really ingenious temperature regulation going on with the driver. Otherwise, where is the heat going? Do you feel much heat being expelled out the front when on high?

Starting from room temperature (probably ~65-70F): After 10 minutes my light was "pleasantly warm". 5 minutes later the area around the switch and fins was "positively toasty" and the entire light was very warm from tailcap to bezel. Obviously subjective, but I'm completely unconcerned about the heat dissipation capabilities of this light. The author of the tear-down thread has also amended his original post saying that things weren't as bad as he originally thought (the heat sink DOES come into contact with the body).

 

[Timothybil]

Can someone post an URL for this other thread?

 

[xevious]

There could be any number of reasons to use glue. Here's a thread about it. Why does it have to be a conspiracy?

No conspiracy suggested, just trying to understand the rationale. Thanks for the link, it was educational.

Starting from room temperature (probably ~65-70F): After 10 minutes my light was "pleasantly warm". 5 minutes later the area around the switch and fins was "positively toasty" and the entire light was very warm from tailcap to bezel. Obviously subjective, but I'm completely unconcerned about the heat dissipation capabilities of this light. The author of the tear-down thread has also amended his original post saying that things weren't as bad as he originally thought (the heat sink DOES come into contact with the body).

I guess it all depends upon the intended use. If you're going to be blazing the EA8 on high most of the time, I'd be concerned about the ability for the emitter and electronics to hold up to the heat if it's not dissipated enough. True, the author did make an amendment on the heat sink disc being in contact with the body, but the fact that you don't feel much heat transmitted through the body leaves question as to how effective it is... unless again, NiteCore has a newfangled engineering technique that has effectively reduced the amount of heat generated.

Can someone post an URL for this other thread?

It's best to limit links from CPF to other light forums. Just use Google and you'll find it.

 

[melty]

I guess it all depends upon the intended use. If you're going to be blazing the EA8 on high most of the time, I'd be concerned about the ability for the emitter and electronics to hold up to the heat if it's not dissipated enough. True, the author did make an amendment on the heat sink disc being in contact with the body, but the fact that you don't feel much heat transmitted through the body leaves question as to how effective it is... unless again, NiteCore has a newfangled engineering technique that has effectively reduced the amount of heat generated.

I'm a little confused as to how you interpreted my post as "you don't feel much heat transmitted through the body". Maybe you meant that as just a general "you".

Perhaps I should have qualified the term "positively toasty". I meant that the light was hot around the switch and fin area. The entire light was very warm. This means that I feel a lot of heat being transmitted through the body. I don't have many large lights at the moment, but my subjective experience leads me to believe that the circuitry does generate as much heat as any other light, and that the heat generated is being dissipated as well as any other light (at this price point).

 

[jayflash]

For many years I carried a Princeton Tec Surge in the flashlight loop of my electrician's pouch. It was designed for the old 2D lights and the Surge was even shorter, much brighter, and wide enough not to slip through. Unfortunately, they weren't reliable and the 8-cell carrier was part of the problem. After three Surges, I gave up and replaced it with a slightly smaller, and much much brighter, single 26650 cell, Maelstrom from 47's.

Eight AA's weren't too much, but they're better if directly loaded without the many extra contacts and added size of a carrier. I'd have kept my Surge had it been reliable. Still, the 26650 liIon cell is more size efficient and has a capacity of ~4000mAh. I'd like to see more of these than having to charge sets of eight AA's.

 

[Stereodude]

Yes it turns out it's all marketing hype, just another typical Chinese Flashlight, no wonder why they put so much loctite on the threads, clearly they didn't want anyone looking at what is really inside......now it gives me a sick feeling how the other models are really made too; the heat fins are worthless marketing hype.

How do you know that? Have you measured the junction temperature of the LED while it's running to know it's getting too hot?

The output graphs selfbuilt generated don't show a fall off of brightness over time as the light heats up. Clearly the LED isn't overheating or it would demonstrate output fall off. Could the heatsinking be better? Sure. Is the heatsinking of the light inadequate? There doesn't seem to be any empirical evidence of that.

 

[RedForest UK]

The output graphs selfbuilt generated don't show a fall off of brightness over time as the light heats up. Clearly the LED isn't overheating or it would demonstrate output fall off. Could the heatsinking be better? Sure. Is the heatsinking of the light inadequate? There doesn't seem to be any empirical evidence of that.

This.

 

[xevious]

Perhaps I should have qualified the term "positively toasty". I meant that the light was hot around the switch and fin area. The entire light was very warm. This means that I feel a lot of heat being transmitted through the body. I don't have many large lights at the moment, but my subjective experience leads me to believe that the circuitry does generate as much heat as any other light, and that the heat generated is being dissipated as well as any other light (at this price point).

Yes, that does qualify the definition a bit better. To me, "toasty" means you can still touch it without burning your fingers. But from what you've now said, it does sound like the light is doing some decent heat transfer, which is good news. Still, the EA8 is probably not a good candidate for driving hard on high. For general purpose long distance throw, it seems competent for the price.