techwg
Flashlight Enthusiast
Hey, sorry if this has been asked before, but can the Fenix TK11 take AW RCR123 batteries safely?
Fenix TK11 RCR ?
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mdocod
Flashaholic
fenix-store said:
Don't think I'd try.
techwg
Flashlight Enthusiast
I saw that on the fenix-store, i just want to clarify that is set in stone, and if so, why would they improve the design and add the function of a new battery type, and take away another good and popular type? Is this just too much on the safe side?
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Marduke
Flashaholic
The TK10 and P3D says 3v CR123's also, but we all know that they take RCR123's just fine.
I have yet to see a definitive statement one way or the other, either through testing or official statement.
I have yet to see a definitive statement one way or the other, either through testing or official statement.
mdocod
Flashaholic
Well, the P3D/Tk10 did not include a statement in their specification to specifically avoid the RCR123, the TK11 does....
It has been in my observation, that when they build a buck regulated light for use on a pair of CR123s, it's almost impossible for it not to be compatible with higher voltage as most of the components that get used can tolerate a wide range of input voltage.
It has also been in my observation, that when you make a boost regulator, the same regulator seems to crop in for a wide range of input voltages, liker for 1.2V NIMH single cell lights, and for 3.0V CR123s....
But when you make a boost/buck regulator that is designed to be optimized around a power source that will spend part of it's discharge slightly above and part of it slightly below the Vf of the LED, the design seems to run into some problems. I have seen a number of "boost/buck" that operate from ~0.9-4.2V, and a number of "boost/buck" that operate from ~2.7-6V, I personally don't see why [wider ranges] can't be done, I'm positive that it can be, but there are a number of products on the market that hold true to these observations.. (Tiablo A8, Many DereeLight modules, Jetbeams etc)
As an alternative, it's POSSIBLE that the TK11 is not a true buck/boost circuit, and is in fact, much like the Tiablo A9, LumaPower M1/MRV, and a whole host of other (DX/KD) buck-only regulated lights that happen to have room for an 18650, and just run, for the most part, direct drive on the 18650. If this were the case, then the TK11 may very well be compatible with a ~9V power source, but would be very disappointing as it would mean that the TK11 is not performing in regulation as it's features chart suggests, from what I have read thus far on the TK11, it sounds like maybe it doesn't run in very good regulation on the 18650, so this may be the case after-all.
I was noticing in that features list, that the TK11 runs almost TWICE as long on an 18650 on turbo mode than it does on 2xCR123s, the only way this could be true is if it is not at full output through the run. Some 18650s do have a little more capacity than a pair of CR123, but not 80% more, 10-20% is more like it.
so maybe it's just a P3D/TK10 style circuit with the low-battery indicator stripped off.
Eric
It has been in my observation, that when they build a buck regulated light for use on a pair of CR123s, it's almost impossible for it not to be compatible with higher voltage as most of the components that get used can tolerate a wide range of input voltage.
It has also been in my observation, that when you make a boost regulator, the same regulator seems to crop in for a wide range of input voltages, liker for 1.2V NIMH single cell lights, and for 3.0V CR123s....
But when you make a boost/buck regulator that is designed to be optimized around a power source that will spend part of it's discharge slightly above and part of it slightly below the Vf of the LED, the design seems to run into some problems. I have seen a number of "boost/buck" that operate from ~0.9-4.2V, and a number of "boost/buck" that operate from ~2.7-6V, I personally don't see why [wider ranges] can't be done, I'm positive that it can be, but there are a number of products on the market that hold true to these observations.. (Tiablo A8, Many DereeLight modules, Jetbeams etc)
As an alternative, it's POSSIBLE that the TK11 is not a true buck/boost circuit, and is in fact, much like the Tiablo A9, LumaPower M1/MRV, and a whole host of other (DX/KD) buck-only regulated lights that happen to have room for an 18650, and just run, for the most part, direct drive on the 18650. If this were the case, then the TK11 may very well be compatible with a ~9V power source, but would be very disappointing as it would mean that the TK11 is not performing in regulation as it's features chart suggests, from what I have read thus far on the TK11, it sounds like maybe it doesn't run in very good regulation on the 18650, so this may be the case after-all.
I was noticing in that features list, that the TK11 runs almost TWICE as long on an 18650 on turbo mode than it does on 2xCR123s, the only way this could be true is if it is not at full output through the run. Some 18650s do have a little more capacity than a pair of CR123, but not 80% more, 10-20% is more like it.
so maybe it's just a P3D/TK10 style circuit with the low-battery indicator stripped off.
Eric
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Marduke
Flashaholic
Where? It just says to use two CR123 cells, same as the TK10 and P3D specs.
mdocod
Flashaholic
the same place I just copied the features from:
https://www.fenix-store.com/product_info.php?cPath=22_85&products_id=497
https://www.fenix-store.com/product_info.php?cPath=22_85&products_id=497
Marduke
Flashaholic
the same place I just copied the features from:
https://www.fenix-store.com/product_info.php?cPath=22_85&products_id=497
Well alrighty then, I guess that qualifies as confirmation of an official source. Must be a fairly new addition to the page.
techwg
Flashlight Enthusiast
I emailed fenix directly, and this is what they said to me:
I asked them if it was ok to run RCR123 batteries like AW RCR123, so it apparently seems you can use them.
I asked them if it was ok to run RCR123 batteries like AW RCR123, so it apparently seems you can use them.
unique
Enlightened
also AW's 18650?
techwg
Flashlight Enthusiast
It was designed to take 18650, so it does not matter what the sticker on it is, but i would trust AW products completely. I personally dont use that size, i only use CR123 size ones, like his RCR
mdocod
Flashaholic
so they say not to use them in the features, and now we have an individual service rep saying that they are fine...
I'm going to assume at this point that either a light is about to get fried, or the TK11 is not regulated on 18650s. bummer either way as it likely means they just bored out a TK10, disabled the low-battery warning, claimed regulation on an 18650, and ran with it.
Fenix makes nice lights, but I think this one was rushed to the table in an attempt to get something into the 18650 market.
I'm going to assume at this point that either a light is about to get fried, or the TK11 is not regulated on 18650s. bummer either way as it likely means they just bored out a TK10, disabled the low-battery warning, claimed regulation on an 18650, and ran with it.
Fenix makes nice lights, but I think this one was rushed to the table in an attempt to get something into the 18650 market.
Marduke
Flashaholic
Do I smell a TK12 over the horizon? or a TK11 V2.0?
TONY M
Flashlight Enthusiast
+1
It is not up to Fenix's usual top standards when it comes to regulation.
I would like to see a well regulated 18650 Fenix light.
techwg
Flashlight Enthusiast
I dont, i think they will wait till a new LED. Theres only so many things you can change, when your still getting basically the same runtime, and brightness. They need NEW LED's IMO
TONY M
Flashlight Enthusiast
I would buy an 18650 ONLY TK11 if it was regulated well.
I have been bored with Q5's for months now.
I'd like newer emitters but really if the upgrade isn't really noticible then it doesn't bother me to stick with the old Q5.trucker1964
Newly Enlightened
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Maybe someone could explain to me how this whole regulation thing works. I too wrote to Fenix about the regulation and they told me the light was regulated in turbo mode with cr123 cells but not with 18650 cells.
How does the light know what batteries you have?
Two cr123 cells would give you 6volts so does that mean higher voltage gets regulated?
If so wouldn't two rcr123 cells (7.4-8.4 volts) also get regulated?
What they told me was you get constant 225 lumens with cr123 cells but not the 18650. They told me you need a minimum of 3.9 volts to output 225 lumens. They said that you would get constant 60 lumen output with either cells. Is this light really regulated?
Why cant they regulate at any voltage? doesn't having a boost circuit mean when you voltage goes below 3.9 volts it gets boosted up to 3.9?
I'm new to this technology could someone explain. Thanks.
How does the light know what batteries you have?
Two cr123 cells would give you 6volts so does that mean higher voltage gets regulated?
If so wouldn't two rcr123 cells (7.4-8.4 volts) also get regulated?
What they told me was you get constant 225 lumens with cr123 cells but not the 18650. They told me you need a minimum of 3.9 volts to output 225 lumens. They said that you would get constant 60 lumen output with either cells. Is this light really regulated?
Why cant they regulate at any voltage? doesn't having a boost circuit mean when you voltage goes below 3.9 volts it gets boosted up to 3.9?
I'm new to this technology could someone explain. Thanks.
Splunk_Au
Enlightened
To put it simply,
because it uses a buck circuit which means input voltage is required to be higher than the forward voltage of the XR-E, about 3.6V on average. Taking into consideration some effeciency loss of the circuit would explain the 3.9V minimum required.
This leads me to think that the TK11 uses the exact same circuitry as the TK10. The only thing Fenix took so long to do was make the internal diamter of the battery tube wider to accomodate 18650 batteries. We can see that the wall of the battery tube is much thinner than the TK10, which for me makes it less of a "tank" in terms of toughness as compared to the TK10.
because it uses a buck circuit which means input voltage is required to be higher than the forward voltage of the XR-E, about 3.6V on average. Taking into consideration some effeciency loss of the circuit would explain the 3.9V minimum required.
This leads me to think that the TK11 uses the exact same circuitry as the TK10. The only thing Fenix took so long to do was make the internal diamter of the battery tube wider to accomodate 18650 batteries. We can see that the wall of the battery tube is much thinner than the TK10, which for me makes it less of a "tank" in terms of toughness as compared to the TK10.
Marduke
Flashaholic
Ok, there is a definitive answer from both fronts. 8.4v is max
