Hot SRT7

eljayem1

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Jun 20, 2014
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Hi again,

A little while ago I asked for opinions on the Nitecore SRT7, and recently bought one. Thanks all for your input.

I do like this torch- lots of functions and it's great having control over brightness. I used XStar batteries and had no problems, although full power was hardly used. The torch got warm but nothing extreme.

I then used unbranded 18650s bought from Torch Direct and on full power after about 7mins the torch gets uncomfortable to hold. A couple of minutes later and it's unbearable.

Has anyone else had problems? How hot should a torch get?

I tried the batteries in my Klarus XT11 and it didn't get overly hot.
 

Str8stroke

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Nov 27, 2013
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There are a few variables I can think of. Ambient temperature the same? Charge levels the same? Output levels the same? Run times measured? Know what I mean? I use a Fluke thermal imaging meter & a Fluke voltmeter to give me that kinda data in order to have a more "scientific" reading of performances.

But, just a guess. Charge levels may be different.
 

Taz80

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Jun 11, 2014
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CT
Depending on the model XT11 you have, the SRT7 will draw more current to alot more. Its probably the batteries heating up. If the batteries are not very good they have more internal resistance which causes them to heat up. You really need to use high quality batteries in high output lights like the SRT7.
 

Moonshadow

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Is it hot at the bezel end or the body ?

If it's the body getting hot, that would indeed seem to implicate the batteries as Taz80 suggests.

You've probably already tried this, but switching back to the original batteries would confirm if it's a battery problem.
 

CelticCross74

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Sounds like you are using an unprotected cell. Unprotected cells can be unpredictable in lights meant to use protected cells which I believe my SRT7 was meant for
 

eljayem1

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Jun 20, 2014
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Thanks for the input.

It's the head and the body of the torch that gets very hot fairly quickly. I've also noticed that you don't get any warning when they're about to die, you're supposed to get a warning at 50% with a slow blink of the small LED on the head then again with a faster blink when they are about to die.

These batteries are also very long and thick, they just fit inside the charger.

I can only assume it is the batteries and buy some others. These cheap batteries still cost me around £10 each, so not so cheap!

Would anyone recommend X Star or AW?
 

thedoc007

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Feb 16, 2013
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It's the head and the body of the torch that gets very hot fairly quickly. I've also noticed that you don't get any warning when they're about to die, you're supposed to get a warning at 50% with a slow blink of the small LED on the head then again with a faster blink when they are about to die.

I can only assume it is the batteries and buy some others. These cheap batteries still cost me around £10 each, so not so cheap!

Would anyone recommend X Star or AW?

Xtar and AW are both fine. So are Nitecore, Keeppower, SoShine, Redilast, Eagletac, and more. Keeppowers are probably my personal favorite. They offer protected cells with lower internal resistance than most. But any of those brands will do fine...if you can find a good deal on them, just go for it. They all use Panasonic cells, anyway.

Did the low voltage indicator work with the Xtar cells? Is there a reason you can't just go back to using those, since they seemed to work better for you?

Everybody's opinion will be different as to exactly what temperature is too high. But as a rule of thumb, if the light is too hot for you to hold continuously, you may be damaging the light. I've had lights get this hot, both accidentally and in testing, and so far only one light has died from that. But better to err on the side of too cool, rather than trying to see how long it can last when overheated.
 

ACruceSalus

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Mar 2, 2014
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I have an SRT7 and as a test when I first got it I put it on turbo using Keeppower 2400 mAh protected batteries. Runtime was about 1.75 hours and the voltage dropped from 4.20 to 3.25. The red voltage LED was blinking faster than I could count. I was able to touch the head but it became uncomfortable in short order. The body was warm but not uncomfortable to hold. So maybe the batteries as others have suggested.
 

Stanley Spadowski

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Aug 19, 2014
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If heat is happening with the crap batteries, where it wan't with the Xtar, you need to toss those other batteries pronto.

I'll bet those batteries heating up aren't rated higher than ~1-2A continuous discharge max. They probably have a crap or mismatched protection circuit to boot. Dangerous combination.
 

subwoofer

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May 5, 2010
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Hove, UK
Hi again,

A little while ago I asked for opinions on the Nitecore SRT7, and recently bought one. Thanks all for your input.

I do like this torch- lots of functions and it's great having control over brightness. I used XStar batteries and had no problems, although full power was hardly used. The torch got warm but nothing extreme.

I then used unbranded 18650s bought from Torch Direct and on full power after about 7mins the torch gets uncomfortable to hold. A couple of minutes later and it's unbearable.

Has anyone else had problems? How hot should a torch get?

I tried the batteries in my Klarus XT11 and it didn't get overly hot.

Honestly, your description sounds perfectly normal. If a light has good heat sinking and a high maximum output, its head will get hot. As the head and body are attached, the body gets hot too. This is normal. Many lights get very hot. The smaller the light and higher the output, the more you notice. Often the highest output modes can only really run for a few minutes without active cooling.

To me this doesn't sound like a cell issue at all. If it were a cell issue, then the highest output mode would not work reliably.

If by unbranded you mean the purple ones described as made by Young Voyage, then they say they are protected.
 

CelticCross74

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Aug 30, 2014
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Fairfax Va
Ive got an SRT7 and only use name brand 3400mah cells. My light will only get warm at the most even after leaving it on high for a half hour. Dftly the cells.
 
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