New LOGAN LED flashlight

[busseguy]

Anybody else got one of these yet?

 

[damn_hammer]

I keep checking back on this thread for some determination on the difference in brightness between primary, and secondary battery. Is this one off, or design intent?

 

[fyrstormer]

I bought a brass McKinley that took a dump on me, and I sent it back to supposedly be exchanged for a brass Logan. If/when it arrives, I'll see what I can see.

 

[easilyled]

.....
The Vf isn't actually a constant, it's just a very steep curve.....

:thinking:

Please explain what you mean by this.

Vf is the forward voltage of an led and is a set value for the current that the led is driven at.

For example, one led may have a Vf of 3.2 when driven at 700ma, another might have a higher Vf of 3.6 when driven at this current. These results are reproducible for each led whenever they are driven at that current.

Its true that it can slightly change with time and use, but this is not what you implied.

When you are working out the power that the led consumes you need to multiply its Vf (at the current being supplied) by the current.

Its in this context that I said that the Vf is a constant for a particular led at a particular current.

 

[fyrstormer]

:thinking:

Please explain what you mean by this.

Vf is the forward voltage of an led and is a set value for the current that the led is driven at.

For example, one led may have a Vf of 3.2 when driven at 700ma, another might have a higher Vf of 3.6 when driven at this current. These results are reproducible for each led whenever they are driven at that current.

Its true that it can slightly change with time and use, but this is not what you implied.

When you are working out the power that the led consumes you need to multiply its Vf (at the current being supplied) by the current.

Its in this context that I said that the Vf is a constant for a particular led at a particular current.

http://en.wikipedia.org/wiki/Diode#Current.E2.80.93voltage_characteristic

While it's possible I'm reading this graph wrong, I believe what it's saying is the diode's resistance increases slightly as the voltage increases, so at 3.5v its Vf might be 3.1v but at 4.5v its Vf might be 3.5v instead.

 

[easilyled]

http://en.wikipedia.org/wiki/Diode#Current.E2.80.93voltage_characteristic

While it's possible I'm reading this graph wrong, I believe what it's saying is the diode's resistance increases slightly as the voltage increases, so at 3.5v its Vf might be 3.1v but at 4.5v its Vf might be 3.5v instead.

I will leave that to the experts. I've always thought that current is a much more significant factor in affecting both led output and the forward voltage of any given led, than the voltage that is supplied.

Peak claims that 1A of current is supplied, regardless of battery voltage and this is why I'm surprised that an RCR123 seems to provide three times as much output as an ordinary CR123.

I'm pretty sure that with a CR123, the led is seeing nothing like 1A. That's the simple and most likely explanation.

In any case, this observation doesn't detract in my opinion from the LOGAN being a very nice light.

In fact, if all LOGANs follow this behaviour, which I would imagine they do, then it gives more options to the user.

 

[boness]

Very nice !

 

[Galiphrey]

I will leave that to the experts. I've always thought that current is a much more significant factor in affecting both led output and the forward voltage of any given led, than the voltage that is supplied.

Peak claims that 1A of current is supplied, regardless of battery voltage and this is why I'm surprised that an RCR123 seems to provide three times as much output as an ordinary CR123.

I'm pretty sure that with a CR123, the led is seeing nothing like 1A. That's the simple and most likely explanation.

In any case, this observation doesn't detract in my opinion from the LOGAN being a very nice light.

In fact, if all LOGANs follow this behaviour, which I would imagine they do, then it gives more options to the user.

Maybe it depends on the fortitude of your CR123. Perhaps the boost circuit is set up to boost to 1A from 3V, but to less from less than 3V (where the output current may sag as the input voltage sags, maybe in order to be kind to your battery). Just a guess. (shrug) Connect it to a solid 3V power supply and see what it does....

 

[easilyled]

Maybe it depends on the fortitude of your CR123. Perhaps the boost circuit is set up to boost to 1A from 3V, but to less from less than 3V (where the output current may sag as the input voltage sags, maybe in order to be kind to your battery). Just a guess. (shrug) Connect it to a solid 3V power supply and see what it does....

It was a brand new fresh CR123 cell that measured 3V on the multimeter.

 

[Galiphrey]

It was a brand new fresh CR123 cell that measured 3V on the multimeter.

Yeah, but, that's 3V when not loaded. It'll sag under heavy load. Clarify: I mean, as though there's an internal resistance.

 

[easilyled]

Yeah, but, that's 3V when not loaded. It'll sag under heavy load. Clarify: I mean, as though there's an internal resistance.

Yes, quite possibly. In any case CR123s clearly can't deliver as much juice to the LOGAN as RCR123s, whatever the reason(s).
I don't have something rigged up to supply a set voltage without sagging and apart from a multimeter have nothing in the way of testing.

I think that Curt_R, as the OP of this thread and Peaks's electronic expert, should clarify the situation.
However it appears that he is in no hurry to do so ..... but as stated previously its nevertheless a very nice light with 2 useful outputs with either battery.

Approx 100 lumens with CR123, Approx 300 lumens with RCR123.

 

[busseguy]

I still havent ordered one yet.
I was still waiting to hear others feedback about it first, but Im surprised to not see any new reviews on it.
Ive also heard that this led tends to be green which is kinda scaring me from ordering directly.

 

[Galiphrey]

Heyhey, I just got a brass #8 Logan! Here's the skinny on how the regulation seems to behave (that is -- from a naive black-box perspective. Normally, I wouldn't consider my observations even noteworthy, except that there appears to be a void of info here for the time being.... combined with an understandable curiosity on the matter. If more official information is presented later, then please disregard my post in its entirety.)

First, yeah, the battery that came with my new Logan, which reads 3V under no load, droops to 2.63 volts when you turn the light on and while the light is shining bright into your eyes. That's what I was trying to get at before: maybe it could have still been true that the power consumption of the light is similar between 3V vs. 3.6V, let's say. I think that's what at least easilyled and I were kind of expecting (if the current supplied to the LED is said to be similar through some input voltage range, then the power consumed by the light wouldn't change more than as accounted by variations of conversion efficiency).

Second, the power consumption is not similar between 3V vs. 3.6V. It seems to do this: it holds the input current at 1A for voltages up to 3.6V or so, at which point there's an elbow, and it starts to climb up with increasing voltages up to about 1.5A for 4V. So, examples of what I just said are: Given a 2.2V input, it consumes 2.2W. Given a 3.5V input, it consumes 3.5W. There's an elbow from thereabouts; and then, for example, given a 4V input, it consumes 6W. (I'm guessing normal rcr123's wouldn't be able to hold up 4V, so you wouldn't ever get up to 6W in reality.)

I'm no reviewer, but I can try to make some other little remarks too:

-Don't actually shine it into your eyes. It's really bright.

-It's my first time ordering from RMSK, and they shipped it fast: the same day I think.

-On mine, something to do with the optic or the positioning of the optic makes a purplish artifact on one side. It's minor and only noticeable when white-wall hunting.

-There's no green in the beam. I don't like green-beams either, busseguy. The tint is good -- coolish white -- probably my best-tinted PEAK light actually.

-Just as easilyled was saying, it is a great flashlight whichever way you consider it.

-You should buy one.

 

[fyrstormer]

When I test a brand-new CR123 on my multimeter, it outputs ~8 amps @ 3.2 volts. Granted, it only has to drop a couple tenths of a volt before can can barely manage 1 amp, but still -- if the driver really is constant-current and voltage doesn't matter like EasilyLed says, then a fresh-out-of-the-box CR123 should have no problem providing enough power to run the Logan at full brightness for at least a short time.

 

[RAGE CAGE]

When I test a brand-new CR123 on my multimeter, it outputs ~8 amps @ 3.2 volts. Granted, it only has to drop a couple tenths of a volt before can can barely manage 1 amp, but still, if the circuitry operates the way Peak says it does, a fresh-out-of-the-box CR123 should have no problem providing enough power to run the Logan at full brightness for at least a short time.

So you received your replacement for the deceased Mckinley- the brass Logan? You have been around for a while- how do you think this compares to say a P4? I am assuming the Beam Pattern is smooth- and does it have anything stamped on the gold plated positive contact (H, 8) etc. in typical PEAK fashion? From the optic pic I saw in CPF a while back- it looked like the thick polycarb/urethane- is yours like that also- Do you like it?

 

[fyrstormer]

Haven't gotten mine yet, Peak just got done building another batch of them. I'm just speculating based on how things should work. I'll be giving this a try first-hand as soon as mine shows up, though.

 

[fyrstormer]

My Logan showed up today. Here it is next to its older cousin, which I'm somewhat disappointed to find out I can't buy anymore.

I'm quite impressed with it. It looks like there's a mineral-glass lense over the plastic optic, and if that's the case, it's a very good idea; since the optic is smooth-surfaced unlike the optic in my Eiger, it would show scratches much more readily, and really there's no reason not to protect the optic anyway.

Mine's a #6; I tested it with the 3V CR123 it came with, as well as an unprotected 4.2V RCR123, and I didn't notice any meaningful difference in brightness. To me, that means either EasilyLed's regulator is malfunctioning, or a CR123 just can't feed the higher power rating he ordered.

If anyone here has a Muyshondt Nautilus R2, I'd say my Logan #6 is about as bright as the Nautilus on high mode. I think #6 is just about the perfect brightness for any of the new Peak lights, which is why all of my new Peak lights are #6's.

 

[LED_Thrift]

"Six is good"

 

[damn_hammer]

...
If anyone here has a Muyshondt Nautilus R2, I'd say my Logan #6 is about as bright as the Nautilus on high mode. I think #6 is just about the perfect brightness for any of the new Peak lights, which is why all of my new Peak lights are #6's.

Thanks for this information. Can you compare it to any other lights in the way of brightness.

edit: How is the tint at #6. I've read in other threads that when the XP-G is under driven it can have a greenish hue.

 

[easilyled]

...... To me, that means either EasilyLed's regulator is malfunctioning, or a CR123 just can't feed the higher power rating he ordered......

There is no malfunctioning in the regulator of mine, the CR123 simply cannot support the power consumption for #8. Galiphrey has noted the same for his #8 in post #53.

Edit: I also just remembered that I bought 2 #8s in any case and they both exhibited exactly the same behaviour. One was a gift for someone else.