Fenix TK40 Review - NEW beamshots up

[ruralott]

Re: Fenix TK40 Review

Excellent. Thank you !!!

 

[HKJ]

Re: Fenix TK40 Review

Nice review, but I do not agree with you measurements.

My measurements are:
Off:0.4mA, min:27mA, 212mA, 700mA and max:2.5A

I have a suspicion that the current draw on max is due to losses in the measurement cables (The light has constant output and will increase current if voltage is low).

But the current in off? Why do you have 2 mA and my measurement says 0.4 mA (I am using a Fluke 189 true rms meter, it has a decent precision).
I can give two explanations: A) You meter is not very good or B) There are big differences between the lights.

I would very much like if a few other people could measure the standby current on their light, it is easy to do (If needed I can post a picture on how to do it).

 

[BabyDoc]

Re: Fenix TK40 Review

Very enjoyable read as well as a great review! Keep up the good work!

 

[Wattnot]

Re: Fenix TK40 Review

Okay, I edited my posts above as I did have some errors. My meter is great and I trust it but those Powerexes are in worse shape than I originally thought. I retook all of the measurements just now using only the Eneloops and adjusted the findings. They seem closer to yours now but I still got that initial climb to 3 amps on Turbo before it settled down to a rock solid 2.6. There could be something wrong with the unit. Take a look at your SOS and see if you're getting that odd flash on a couple of the "Os" like I did. If you don't then there could be a little something wrong with my particular TK40.

Nice review, but I do not agree with you measurements.

My measurements are:
Off:0.4mA, min:27mA, 212mA, 700mA and max:2.5A

 

[HKJ]

Re: Fenix TK40 Review

Okay, I edited my posts above as I did have some errors. My meter is great and I trust it but those Powerexes are in worse shape than I originally thought. I retook all of the measurements just now using only the Eneloops and adjusted the findings. They seem closer to yours now but I still got that initial climb to 3 amps on Turbo before it settled down to a rock solid 2.6. There could be something wrong with the unit. Take a look at your SOS and see if you're getting that odd flash on a couple of the "Os" like I did. If you don't then there could be a little something wrong with my particular TK40.

The current at max will depend on the voltage drop in the measurement cables and battery voltage, i.e. if it says 2.5 or 3 A is not really a big question, but probably more about the cables.

I tried to measure the SOS with a optical sensor, you can see the result here:

 

[PhantomPhoton]

Re: Fenix TK40 Review

So it it's down around .3 or so mA, then the parasitic current isn't as bad. Thanks for the update. Makes me feel better about the light knowing it'll sit for more than 3 months.
I do like that beam profile :naughty:

 

[Wattnot]

Re: Fenix TK40 Review

The current at max will depend on the voltage drop in the measurement cables and battery voltage, i.e. if it says 2.5 or 3 A is not really a big question, but probably more about the cables.

I tried to measure the SOS with a optical sensor, you can see the result here:

Ah HA! So it's not just my light doing that second and third "O" blip. There it is right there. Nice work HKJ. Hmmm. Fenix, you should look at that. It's a minor thing, and I'm sure the fella will still get rescued from the mountain top or the drifting boat, but it's still there.

As for my cable lengths . . . hey, I know your meter is good. I looked it up and while it's discontinued, the similar model that replaced it has a FIVE HUNDRED dollar price tag. However, it's not my cables or my meter causing a one time, momentary, slow climb to 3 amps, only to settle back down to 2.6A. Try it yourself but hold the reading for about 30 to 60 seconds and see if it does it on yours. After all, you found the same SOS problem, maybe you'll find that too.

 

[EDC]

Re: Fenix TK40 Review

Thank you for the excellent TK40 review.

I checked the SOS mode on my TK40 & found that it's also doing that odd flash on the second & third dash.

 

[HKJ]

Re: Fenix TK40 Review

As for my cable lengths . . . hey, I know your meter is good. I looked it up and while it's discontinued, the similar model that replaced it has a FIVE HUNDRED dollar price tag. However, it's not my cables or my meter causing a one time, momentary, slow climb to 3 amps, only to settle back down to 2.6A. Try it yourself but hold the reading for about 30 to 60 seconds and see if it does it on yours. After all, you found the same SOS problem, maybe you'll find that too.

I have redone the measurement on high, this time with batteries straight off the charger and I do not agree with you measurements, this time the measurement was steady on 2.3A.

I do not know how you do you measurements, I open the light between the head and the tube. This makes it easy to make the connection for current measurement: One alligator clip wire between tube and head, one alligator clip wire between outer rings and the meter between the center positions.

I have also made a review of the TK40, but it will not be posted here (Because it is in danish).

 

[Wattnot]

Re: Fenix TK40 Review

I have redone the measurement on high, this time with batteries straight off the charger and I do not agree with you measurements, this time the measurement was steady on 2.3A.

I do not know how you do you measurements, I open the light between the head and the tube. This makes it easy to make the connection for current measurement: One alligator clip wire between tube and head, one alligator clip wire between outer rings and the meter between the center positions.

I have also made a review of the TK40, but it will not be posted here (Because it is in danish).

Well I guess we'll have to agree to disagree then! I have a good meter and know how to measure current. Our readings are not that far off anyway. You got 2.5 and I got 2.6. The next paragraph should explain the 2.3 reading you just got.

Nimhs fresh off the charger will give out more voltage (enough to flash an 1185 lamp) which could easily explain your lower reading - especially since it's lower than your ealier 2.5A reading. I don't understand why you find this so odd.

 

[HKJ]

Re: Fenix TK40 Review

Well I guess we'll have to agree to disagree then! I have a good meter and know how to measure current. Our readings are not that far off anyway. You got 2.5 and I got 2.6. The next paragraph should explain the 2.3 reading you just got.

Nimhs fresh off the charger will give out more voltage (enough to flash an 1185 lamp) which could easily explain your lower reading - especially since it's lower than your ealier 2.5A reading. I don't understand why you find this so odd.

I do not find my readings odd (or yours), they are what I expected. But I do not believe that they show the correct current for the TK40, when I look at the battery tube and the head, I see some serious springs and plates, the connection will have a very low impedance when the head is directly connected to the battery tube.
When I do my measurements I use some wires and a meter with an internal impedance, this will give a voltage drop (I have not measured how much) and this voltage drop will force the TK40 to draw some extra current.
If I had wanted a more exact measurement I could have soldered some heavy gauge wire between the battery tube and the head and then use a current clamp to measure the current, but I do not wish to solder on my new light.

 

[Kilovolt]

Re: Fenix TK40 Review

sounds like it's gotta be hanging on by a thread, and tailstanding....not exactly like "any other light"

Once my TK40 is locked out there's still more than 4 complete rounds before you can remove the tailcap. Hardly hanging on by a thread I would say.

Additionally the positive and negative contacts on top of the battery holder have different shape and length. Gravity is not enough to make them both touch the head's PCB. Only the force of the spring in the tailcap can do that. This can be easily verified by putting the holder upright on a table.
Once the tailcap has been unscrewed by the required 2.5 rounds the light can no longer be switched on independently of its position. IMHO there's no need to keep it tailstanding.

 

[BrightMan]

Re: Fenix TK40 Review

I have the TK10 and think about ordering the TK40. For me, primary important is the light output.
Is brightness much more, so the TK40 would be worth the money?

 

[HKJ]

Re: Fenix TK40 Review

I have the TK10 and think about ordering the TK40. For me, primary important is the light output.
Is brightness much more, so the TK40 would be worth the money?

Yes, it is much more, about 3 times more light.

 

[Kilovolt]

Re: Fenix TK40 Review

I have the TK10 and think about ordering the TK40. For me, primary important is the light output.
Is brightness much more, so the TK40 would be worth the money?

The tree is at the back of my garden 40 meters away



the difference in total output is actually higher because TK40 has a much brighter spill.


On the other hand you have to take into account the difference in size



:wave:

 

[flasherByNight]

Re: Fenix TK40 Review

Once my TK40 is locked out there's still more than 4 complete rounds before you can remove the tailcap. Hardly hanging on by a thread I would say.

Additionally the positive and negative contacts on top of the battery holder have different shape and length. Gravity is not enough to make them both touch the head's PCB. Only the force of the spring in the tailcap can do that. This can be easily verified by putting the holder upright on a table.
Once the tailcap has been unscrewed by the required 2.5 rounds the light can no longer be switched on independently of its position. IMHO there's no need to keep it tailstanding.

Good to hear another/different experience, I am only basing my comments on what peoples observations have been. ie in THIS review:

The only way unscrewing the tailcap is going to stop this drain is if you turn it out enough to break the contact AND TAILSTAND THE LIGHT. The springs on both the negative and positive have a long reach so you're going to have to unscrew the tailcap to the point where it almost falls off.

Just goes to show everyones experience can be slightly different

 

[Wattnot]

Re: Fenix TK40 Review

Once my TK40 is locked out there's still more than 4 complete rounds before you can remove the tailcap. Hardly hanging on by a thread I would say.

Additionally the positive and negative contacts on top of the battery holder have different shape and length. Gravity is not enough to make them both touch the head's PCB. Only the force of the spring in the tailcap can do that. This can be easily verified by putting the holder upright on a table.
Once the tailcap has been unscrewed by the required 2.5 rounds the light can no longer be switched on independently of its position. IMHO there's no need to keep it tailstanding.

I understand what you are saying KV but going by when the light shuts off, and assuming that also stops the parasitic drain, is a bad assumption and is not correct. I will explain:

The center coil spring on top is positive. The four spring clips forming an outer ring that surrounds the positive coil spring on the top is negative. However, there is an additional negative contact on the bottom, which makes contact with the tailcap spring. As long as the top spring and bottom spring are making contact, you will have the parasitic drain. I verified this by REMOVING the tailcap and putting my meter between the bottom contact of the battery carrier and the threads on the tube.

As for what I said about tailstanding, I stand by that but even then we really have no way of knowing if we really are breaking contact with the top POSITIVE spring. There is where I am making an assumption. If you unscrew it until it's about to fall off, and tailstand it, contact SHOULD be broken. It seems logical to me.

Thanks!

 

[Kilovolt]

Re: Fenix TK40 Review

You may be absolutely right, however Fenix says that lockout is achieved by unscrewing the tailcap by 2.5 turns and if you check this you can appreciate that after 2.5 turns the light can no longer be operated.

I can not believe that this happens by pure chance and I think that once the switch is no longer operative there is no parasitic current just as the manufacturer says. I am convinced that until the four spring clips are pushed against their contact in the PCB no current can flow.

Probably time will tell. Meanwhile I keep my TK40 laying on one side and with the tailcap unscrewed by 2.5 turns.

 

[HKJ]

Re: Fenix TK40 Review

It would be a bit difficult for the current to run through the tailcap, the switch need to be activated for that to happen. I.e. with the head screwed loose and the switch pressed, it might have some standby current.

Just checking...

It does, the 0.4 mA standby current will flow if the switch is pressed.

 

[Wattnot]

Re: Fenix TK40 Review

Yeah, you're right . . . I hadn't thought about the spring going through the switch so my test from the bottom to the tube doesn't prove that part. This testing has been a pain. It's like trying to see if the refrigerator light is on with the door closed! :mecry: