My 70 gram 2x18650 xml flashlight (wristlight)

degarb

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As I said many times, I never hold my flashlights, because I use them. You cannot often use a light and hold it at the same time, in the real world. And if you use it, the target should be 8-10 hours or more.


I have tried chest lights, belt lights, but found only two types of battery light useful. In addition to the headlamp, there is the wrist light--which can: broaden your periphery vision for walking, backup headlamp when hiking, show texture (in vision area from waist to head level), intensify low areas, help in locating things more quickly than headlamp, and augment headlamp beam intensity and color. Naturally, wristlights aren't for everyone or every task. They work best for walking, or working with one's right hand and holding stuff with left hand.

But your wrist lights need to be much lighter than a headlamp because you are moving your arm about more ferociously than your head. (The hp11 is 180 g w/out batteries, as is many new xml lights).

I know from experience that a 65 g single 18650 light (110 g with cells) works well, weight wise. Just poor runtime. I assume too that if you could keep the total weight under 150 grams (with two liion cells), you should be golden - benefiting from buck efficiency and long runtime.

So, here (in pdf form) is my Non-Tubular, 8 hour (270 lumen flat), 4 K candela, splash proof, comfortable/forgettable, 70 gram wristlight design. I have a ton of unused lights that fail on one specification or another. My focus is on meeting all Specifications, and mistake avoidance. Falling short of any single Specification, or committing a single error, WILL ruin your light.

Beware, form follows function.
 

Microa

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May I ask you, Is there any Pro and Con you don't consider remote battery pack? For example, the battery pack is wore on the fore arm and the light head to the wrist.
 

degarb

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May I ask you, Is there any Pro and Con you don't consider remote battery pack? For example, the battery pack is wore on the fore arm and the light head to the wrist.

There are cons to remote pack: 1. Cord durability is bad enough with factory made lamps, but I have had wretched sucess making my own. Light lifetime with cord seems about 12 months max factory or homemade. I think lifespan needs to be closer to 3-7 years, minimum. Even if we hit 220 lpw at 700 ma in 3 years. 2. Carting around each day 3-4 headlamps + 3-4 wristlights in a single bookbag. (tangling issue.) 3. Also, there seems to be a big psychological issue with 2 minutes strap up time v. 7 seconds. 4. I have tried cool looking shoulder mp3 players in past at gym, but didn't like the feel. Though, I probably would improve upon the straps of store sold shoulder mp3 player holders; I probably would attach an additional (to two elastic velcro upper arm straps) thin elastic neck strap to the pack. This would allow the arm straps to be secured more loosely. 5. Overcoming the above 4 reservations may be technically possible, but would take time to reach elegance and perfection. This is plan #B in my book. So, plan #A needed to be fully explored first. ... I welcome anyone to build the shoulder battery pack version. This would save me time.

All but one of fenix headlamp offerings (not counting old bt20 bike light that lacks a stock headstrap) this year, offer too whimpy runtime and lux output for working lights. But, I haven't purchased the hp30 yet, because of cord issue and suboptimized run levels. I own two remote battery corded xml headlamps already, but have retired both. And pulled out the headband mounted Fenix BT20 shortly, only for certain jobs, this last year.

The Pro list of a remote battery pack is obvious. Weight on wrist (lower weight means the strapping can be more lightly tightened); size of battery pack could be jacked up to an optional 3, maybe 4 cells (which gets into a battery management issue); swappable battery formats; more feasible higher current levels (bigger heatsink, heat sinking into arm); less chance of some working accidentally taking the thing home; may discourage workers from taking it off/putting back on, repeatedly throughout day.
 
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Microa

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Are you going to build the prototype 5 using AMC7135 x 2 driver? I have estimated that an XML-2 U2 outputs 300 lumens at 700mA driving current which consumes about 2W. If you power it up with 2 pieces of Panasonic NCR18650B, I am very sure it has 8 hours plus run time.
 

degarb

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Are you going to build the prototype 5 using AMC7135 x 2 driver? I have estimated that an XML-2 U2 outputs 300 lumens at 700mA driving current which consumes about 2W. If you power it up with 2 pieces of Panasonic NCR18650B, I am very sure it has 8 hours plus run time.

With a cold 1A tint, you could get 300 lumens, minus reflector/lens loss and loss due to any inadequate heatsinking. Also, I would like to objectively test overall output of a plastic v, aluminum reflector http://www.optiforms.com/metallic.htm.

I see you read my pdf. Didn't think anyone would. Doubt if many have. But so many mistakes and design points to learn from—even if you have no appreciation for its logical, and proudly amateur, form.


You can see I mounted the Buckpuckmore elegantly on front on my Prototype #4 (p4) (allowing a tad more heat sink on the deck). But, you probably cannot see the thin 1.5 mm strip of aluminum that runs across 1/4th of the buckpuck and connects to heatsink. The controller gets a little hot, as I assume an AMC 7135would. I probably could mount a 2x350ma controller board (modded from the available 3xboard) in same area; I do not know how exactly how to heatsink, or if required.

Now, my nondimming buckpuck, I have twice tested to last nearly exactly at 9 hours, with flat output (to 2.5 volt per cell, where the Panasonic protection kicks in. source: fasttech). I have tested the dimming buckpuck at %88 current (2xPanasonic 3400 from kaidomain with 3v cutoff protection), where I got something over 10 hours (can't remember exactly). I tested at 88% since this is the threshold where, to the eye, it is indistinguishable to %100 tailcap draw. In fact, I am more typically using my lights 12 hours a day (dimming as needed) on same 2 Panasonic 3400s, counting mornings and night+ job time. I like the control of the dimmer.

Also, with the buckpuck, there is zero dimming as the cells drain (much like my Fenix lights). This is tested by lux meter. Flat lux, with the buckpuck, at 8.5 hours as at hour #1. (Maybe 340 ma on hour 1 per cell and 390 ma at 7.5 hours and 420 ma near end.)


On the other hand, my int-outdoorflashlight with Nanjg 101-AK-A1 (4*7135) circuit board, dims a bunch, depending on the voltage of the cells. So, while I read the spec sheet of the amc7135 as CC, I am not seeing CC, exactly, in real life. I am not understanding something. Also, the drop-ins that I have bought from dx, fasttech, and kai, dim or brighten depending on the cell's energy and drain. I don't get it.




Other light notes, not in pdf:

The head angle off to left: 10 to 20 degrees is good.

Water/moisture entry into pill is a concern, not yet a reality. On next build: I might try to lightly superglue glass lens onto the reflector, then use traditional DAP33 window glazing (which is removable and probably not able to seep into the reflector like paintable-we need tape to stick- silicone) before aluminum taping and banding.

Also, I would like to objectively test overall output of a plastic v, aluminum reflector. http://www.optiforms.com/metallic.htm. Then I would like to see a p60 brass, directly thermal epoxied to heatsink, better mated to the aluminum reflector + heasink would cool front the end. Would take front end temp. measurements again. Not sure if weight would be added (by extra brass or lost (loosing some glue and some aluminum). (However, this test is will conflict with a plastic reflector, 65 gram light, test.

Just got a pound of zinc, and 10 ounces of original JBweld. This glue should be heavier in future build than AA + AS. Not sure how much it will matter.

The light wristlight design does mount up easily onto shop vac hose, paint roller (18 inch tested), bike handle (which is nice for flexibility of usage). I am concerned with paint spatters onto heatsink (something I put some thought into, unlike store lights), which can be mitigated by carrying roll of aluminum foil to be used when spraying or attaching to roller (but in real life, wouldn't often happen).
 
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Microa

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With a cold 1A tint, you could get 300 lumens, minus reflector/lens loss and loss due to any inadequate heatsinking. Also, I would like to objectively test overall output of a plastic v, aluminum reflector http://www.optiforms.com/metallic.htm.

I see you read my pdf. Didn't think anyone would. Doubt if many have. But so many mistakes and design points to learn from—even if you have no appreciation for its logical, and proudly amateur, form.


You can see I mounted the Buckpuckmore elegantly on front on my Prototype #4 (p4) (allowing a tad more heat sink on the deck). But, you probably cannot see the thin 1.5 mm strip of aluminum that runs across 1/4th of the buckpuck and connects to heatsink. The controller gets a little hot, as I assume an AMC 7135would. I probably could mount a 2x350ma controller board (modded from the available 3xboard) in same area; I do not know how exactly how to heatsink, or if required.

Now, my nondimming buckpuck, I have twice tested to last nearly exactly at 9 hours, with flat output (to 2.5 volt per cell, where the Panasonic protection kicks in. source: fasttech). I have tested the dimming buckpuck at %88 current (2xPanasonic 3400 from kaidomain with 3v cutoff protection), where I got something over 10 hours (can't remember exactly). I tested at 88% since this is the threshold where, to the eye, it is indistinguishable to %100 tailcap draw. In fact, I am more typically using my lights 12 hours a day (dimming as needed) on same 2 Panasonic 3400s, counting mornings and night+ job time. I like the control of the dimmer.

Also, with the buckpuck, there is zero dimming as the cells drain (much like my Fenix lights). This is tested by lux meter. Flat lux, with the buckpuck, at 8.5 hours as at hour #1. (Maybe 340 ma on hour 1 per cell and 390 ma at 7.5 hours and 420 ma near end.)


On the other hand, my int-outdoorflashlight with Nanjg 101-AK-A1 (4*7135) circuit board, dims a bunch, depending on the voltage of the cells. So, while I read the spec sheet of the amc7135 as CC, I am not seeing CC, exactly, in real life. I am not understanding something. Also, the drop-ins that I have bought from dx, fasttech, and kai, dim or brighten depending on the cell's energy and drain. I don't get it.

The XML-2 U2 I referred to is neutral white 3C tint.

Try to make a thermal path to the amc7135's exposed pad which is at the top of the SOT-89 package and is connected to the ground trace at the edge of the board. Those driver boards are designed for flash light. If you will adhere it to the heatsink, make sure you have isolated the positive battery contact point at the bottom layer. The LED+ solder pad on the top layer of the driver board is connected to the B+ contact through the vias. You can connect the B+ and the LED+ at the same solder pad. The amc7135 is a linear current regulator which consumes the excessive power as heat. For a fresh charged battery to drive an XML-2 at 700mA, they dissipate 0.945W. W = ( Vb - Vf ) x I = (4.2V-2.85V) x 0.7A = 0.945W
Personally, I prefer a buck driver. If you don't require dimming, the AX2002 driver IC board would be a good choice.
 
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degarb

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The XML-2 U2 I referred to is neutral white 3C tint.

Try to make a thermal path to the amc7135's exposed pad which is at the top of the SOT-89 package and is connected to the ground trace at the edge of the board. Those driver boards are designed for flash light. If you will adhere it to the heatsink, make sure you have isolated the positive battery contact point at the bottom layer. The LED+ solder pad on the top layer of the driver board is connected to the B+ contact through the vias. You can connect the B+ and the LED+ at the same solder pad. The amc7135 is a linear current regulator which consumes the excessive power as heat. For a fresh charged battery to drive an XML-2 at 700mA, they dissipate 0.945W. W = ( Vb - Vf ) x I = (4.2V-2.85V) x 0.7A = 0.945W
Personally, I prefer a buck driver. If you don't require dimming, the AX2002 driver IC board would be a good choice.

Good info. Never knew neutral 3c u2 xml2s existed before. I see the u2 3c tint at alibaba, not elsewhere yet. Price is $19. And the ax2002 is $9 at dx. So, neither too cheap. (Lights with dimming are more flexible for home use, where some of our lights get hundreds of hours before battery swaps. For me, lights with no dimming grate upon my nerves, when I know I could be using less light. I never looked into separate pwm controllers for these.)

The other advantage of 2s is that if one cell is not making contact, you know it immediately. Rather than early dead light, and not knowing if it is a cell, or did I charge something wrong (I do check voltage off charger-even with my protected, new panasonic 3400s, since overcharging is the cause of the well known explosion risk.). This assumes I am one using the light.
 
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Microa

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Regarding the heatsink, my find out is that at about 30C ambient temperature, the temperature of the heatsink (37x37x23mm) will raised to around 55C. I think 55C is a little bit hot but acceptable.

This is my testing driver and heatsink.

P1110724_zps179ed9d5.jpg
 
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degarb

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Regarding the heatsink, my find out is that at about 30C ambient temperature, the temperature of the heatsink (37x37x23mm) will raised to around 55C. I think 55C is a little bit hot but acceptable.

This is my testing driver and heatsink.

P1110724_zps179ed9d5.jpg


Magnesium heat sink. Interesting. No time to research it now.

This some info I was after!: "(37x37x23mm) will raised to around 55C. I think 55C is a little bit hot but acceptable."

Piture looks like a 1 watt 30-40 lpw Lux1, though, I am using xml2 150 lpw, driven at 2 watts max. So, maybe it should be equal. Mostly: Also, trying to use reflector, and a tad of base (though hardly signif) to help pull some of the heat out.
 

Microa

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The LED is an XPG. I simulated the 2 watts of heat load. The PCB has a temperature test pad that I can attach a temperature sensor to estimate the junction temperature of the LED.
 
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