Classic Review: LED Lenser P14 TIR zoomy

6 posts / 0 new
Last post
Fritz t. Cat
Fritz t. Cat's picture
Offline
Last seen: 1 year 4 months ago
Joined: 05/07/2013 - 00:33
Posts: 2535
Location: Si Valley
Classic Review: LED Lenser P14 TIR zoomy

At $26.99 this is another old stock bargain from Tmart. (Unfortunately, they are now sold out.):


★ ★ ★ ☆ ☆

Pros:

  • Excellent build and finish.
  • Fresnel type optics that focus the whole output of the LED.
  • Good throw and large focused spot.
  • Good flood.
  • Very nice unusual user interface.
  • No blinky modes, or pulse width modulation or ripple in any mode — pure DC.
  • Two of the driver resistors are at the tail, reducing heat in the head.
  • Good output without needing lithium cells.
  • Smooth head slide and switch action.
  • Nice simple shape with compound curves.

Cons:

  • It has an old XR-E, so total light output is limited in stock form.
  • The arrangement of the battery is not space efficient, so it is very bulky.
  • It doesn’t take lithium ion cells.
  • The reliability record of these lights reflects their innovativeness more than their build quality.
  • This brand is usually over priced.

Click for full size.

The battery holder is similar to that of the Lenser P7.2 http://budgetlightforum.com/node/34815, except for the arrangement of the cells.

Only half of the volume of the battery tube is actually filled with battery.

Redundant battery holder contacts.

The pill and LED are similar to those of the POP lite T62, $30.41 from DX http://www.dx.com/p/pop-lite-t62-cree-xr-e-q5-180lm-4-mode-white-light-z....
http://budgetlightforum.com/node/35259

The feature that marks it as old stock and takes off one star is the little old XR-E LED. But that can be fixed.

The optics is standard Lenser/Coast/POP lite/Fresnel:

As in the Lenser P7.2 and the POP lite T34, the three mode driver is a mechanical switch and resistors. Pressing the switch part way unconditionally engages an intermittent turbo mode. Pressing it all the way and releasing it cycles between high, low and off. No blinky modes or pulse width modulation, because there is no active electronics to make it blink. To change the modes one solders resistors, rather than re-writing firmware. This uses both the LED and the battery more efficiently than most electronic drivers do.

There is a notch under the sliding o-ring of the pill to break vacuum so it can slide.

Note the very nice threads on the pill. (The pill appears to be die cast.) The build and finish are excellent, though I prefer the more matte finish of the newer P5.2 and P7.2.

The serial number of my example is 223696.

The thing about these lights that sets them apart and ahead is the optics. Rather than some of the light going into spill, as with conventional or one zone TIR reflector, or some of it being lost in throw mode as with an aspheric lens, nearly all of it goes into the spot, whether zoomed in or out. Carclo optics has two zones, but the space behind the convex lens is smaller. This optics differs from Fresnel’s 19th Century lighthouse optics https://en.wikipedia.org/wiki/Fresnel_lens mainly in that there are only two zones, instead of dozens. Judging from the highly sloped transmitting surfaces, and from the limited zoom of the much older Coast/Lenser TT7438CC http://www.ebay.com/itm/231523982515, it appears to have taken some design effort to find a two zone configuration such that the zones don’t interfere with each other or with the LED and its cooling. However there is no obvious advantage in having the minimum number of zones, as shown by the effectiveness of flat Fresnel lenses when they have been used in flashlights, including zoomies.
-

Beam shots, fully charged batteries:

Lenser with Eneloops in high mode on left, TangsFire C8 with protected Panasonic on right, showing shadow setup at lower right

Lenser in turbo on left, TangsFire on right

Lenser in turbo on left, UltraOK SK-68 with IMR AW 14500 on right


-

Problem

In this century, one expects electronics to be more reliable and easier to fix than mechanics, and unfortunately this has been an example. The three way switch stopped going into turbo direct drive while pressed. For an ordinary user, that would not be much of a problem, because high is plenty bright and turbo was only intermittent anyway, but for a flashaholic it had to be fixed.
So I took it apart. The problem was probably no more than a spec of something non-conducting, so taking it apart and putting it back together should have fixed it, but it is a tricky and fragile piece and I am not a racing mechanic like my brother, so I bent the contacts putting it back together. I tried several times to straighten it but could not get it to work reliably, so I gutted the switch and stuck in a one way reverse clicky switch.

I connected it, trimmed things to fit and added a 1 mm. x 16 mm. star as a spacer. Now it works only on turbo and has no intermittent. There is room in the head for an FET driver, but that is another job.
I have had a lot of reliability problems with Lensers and POP lites, but like them anyway because I am an idealist. Maybe Lensers sold for full price with warranty have better quality control, but I doubt it.
-

★ ★ ★ ☆ ☆

Summary:

Overall, this is an very good, interesting and unusual flashlight. It isn’t a budget flashlight, but Tmart has had this old model at a more or less budget price. I take off one star, because, as is, the XR-E LED limits the output. It out throws a well regarded C8, but the spot size is not what one should expect from this optics. The combination of output in the central spot and run time is excellent, perhaps unique for a light that doesn’t require lithium cells. The unusual 4 x AA configuration, with nominal voltage of 4.8 or 6 volts, gets a lot out of the old XR-E and calls for bigger LEDs and less resistors. Reliability problems have been common with these POP lite and LED Lenser lights. (Switch problems were also reported with a full price warrantied Lenser.) I like them anyway, because I am idealistic and I have been able to fix them.
It is now listed as discontinued at Tmart. It can be found elsewhere, but at higher prices.

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。

Edited by: sb56637 on 09/02/2017 - 11:48
Fritz t. Cat
Fritz t. Cat's picture
Offline
Last seen: 1 year 4 months ago
Joined: 05/07/2013 - 00:33
Posts: 2535
Location: Si Valley

Insides and Modification

I got the pill out of the battery tube with penetrating oil, taps with a screw driver through a paper towel, some heating with a propane torch, rubber around the battery tube and pump pliers over a paper towel on the pill. There was no sign of glue. It was just in hard. Only slight scratches.

Unusually, the pill is die cast:

For radical modification, the battery tube measures 30.5 mm. diameter. One 26650 would leave a lot of space, but two would seem to require shortening the tail or the pill. Three AAs abreast does fit, but not the 3 x AA battery carrier that I tried.
-

LED swap and resister elimination

My plan is to bridge the resistor in the head and see how much current I get through an XP-L. Simple but should work. I think I will need to file the pillar on top of the pill shorter to retain the focus with a thick direct copper star.

An XP-L came from Fasttech.

Like the P7.2 it has two resistors attached to the switch to limit high and low modes and one in the head to limit turbo.


-

The tail cap unscrews from the battery holder, leaving the switch attached to the battery holder with four small tight phillips head screws.

The switch does not come open easily.

Two resistors are on the back of the switch, 1 and 24 Ohm. I braided the battery springs. Judging from the Lenser/Coast, there are other steel springs in the bumps that contact the head. The battery holder is made of low melting point thermal plastic, so it needed cleanup with a knife after re-connecting the battery holder end to the switch.


-

I found the third resistor, a big 1.8 Ohm old fashioned resistor with leads, floating in the pill among the thermal elastic and covered by shrinking tube.

I am proceeding with the LED change, rather than testing it without the resistor in the head but still with the XR-E, probably the best configuration for pure throw.
-

The top of the pill was flattened and lowered by the thickness of the star. Without a mill or even a vise that fits it, it came out rounded, but at least there is contact in the middle, and I used plenty of Arctic Silver.

The star was trimmed to about 13 mm. to fit in the white retainer. The retainer didn’t press on the star, so I clipped bits of match stick for spacers. I am getting to like the star headed screws. The same screwdriver fits all the Lensers and the POP lite, and it grips the screws securely without much pressure.

When I put it together, there was a very brief flash and then only a faint glow. It now draws only a quarter of a milliamp. I had to go into a dark room to check the focus! Probably the trouble is that I filed the star down with the XP-L on it. In the past I have found that XM-Ls and XM-L2s stand that sort of treatment, but Philips Rebel’s don’t. Probably the smaller package of the XP-L makes is less mechanically rugged than an XM-L2. Fortunately I have another on order from Fasttech. It is unlikely that it got too much current for the bond wires. If an XP-G2 takes four AAAs, an XP-L should take four AAs.

Here it is with a new XP-L V3 5D, with match stick spacers, ready for the pressure cap.

The new XP-L was already on order from Fasttech when I broke the old one, but it took about a month to arrive. Five packages came at the same time, so maybe packages without tracking pile up at my local post office before they get around to delivering them.

P14 on left, P7.2 on right, high mode (both without the resistor in the head):

The larger LED about makes up for the larger optics, so the spot size is similar. On high the P7.2 is at least as bright, but in intermittent turbo mode, with no resistor, the P14 is brighter.

Turbo later quit working on the P14, and I replaced the switch with a one way reverse clicky, as discussed in the OP.
-

12 Volts possibility

It came up on the XHP-35 thread that a P7 or P14 would work as a 12 V. light with lithium ion cells. http://budgetlightforum.com/node/40733#comment-787156, http://budgetlightforum.com/node/40733#comment-798625 The drivers, consisting only of switches and resistors, would work without modification at other voltages. So the mod. would consist only of substituting a 12 volt LED, shortening the pillar of the pill and trimming a star (without the LED on the star).
-

BLF A6 driver

After the three way switch failed and was replace with a one way switch, I wanted to have modes again but without loss in highest mode brightness. So I added a Banggood BLF A6 driver in the head. There is a huge space in the head, out of which I had taken the single wire leaded resistor. Electrically, I could just hang the driver there like the resistor, but even an FET driver should have cooling at these current levels, so I attached the driver to the top of the contact board.


I drilled a hole in the contact board to be able to melt the solder between the boards. I filled the hole with solder and capped it with solder wick to improve the via connections between the sides of the contact board. I filed away the opposite side of the board from the – vias and ran a braid from the back to the driver ground ring.

Turbo mode output is about the same as with either switch alone, and it now has the very slick Toykeeper user interface and regulated lower modes. It has lost only the uniqueness of the mechanical driver and the ripple free operation of the resister regulated modes. Turbo mode now has a timeout instead of being activated by an intermittent switch.

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。

breinrules
breinrules's picture
Offline
Last seen: 1 year 9 months ago
Joined: 10/04/2014 - 02:25
Posts: 581
Location: Cebu, Philippines

Not 26$ anymore though. The m14 though fatter has better arrangement of cells compared to p14

Fritz t. Cat
Fritz t. Cat's picture
Offline
Last seen: 1 year 4 months ago
Joined: 05/07/2013 - 00:33
Posts: 2535
Location: Si Valley

I still see it listed at $26.99 when I click the top image above.
The M14 appears to have smaller volume and surface, and therefore probably smaller weight. It is a matter of what is comfortable for you to hold. The M14 also has an electronic driver, which some will like better.
Do you see the M14, or any others that I haven’t mentioned, for budget prices anywhere?

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。

breinrules
breinrules's picture
Offline
Last seen: 1 year 9 months ago
Joined: 10/04/2014 - 02:25
Posts: 581
Location: Cebu, Philippines

Fritz t. Cat wrote:
I still see it listed at $26.99 when I click the top image above. The M14 appears to have smaller volume and surface, and therefore probably smaller weight. It is a matter of what is comfortable for you to hold. The M14 also has an electronic driver, which some will like better. Do you see the M14, or any others that I haven't mentioned, for budget prices anywhere?

 

Sad to say cheapest i saw is 90$ (gulp). 

Fritz t. Cat
Fritz t. Cat's picture
Offline
Last seen: 1 year 4 months ago
Joined: 05/07/2013 - 00:33
Posts: 2535
Location: Si Valley

Fasttech also lists a T7 and a P7, similar to the P7.2 but older models and cheaper. Fasttech lists them as 2 mode, which probably means 2 + intermittent turbo, like the P7.2 and the P14.

Flashlight designers should look at lighthouses and pottery.
这些谁设计的手电筒应该看灯塔,以及在陶器。