Energizer folding light

[RonM]

Picked up the Energizer folding light at Walmart today and I like it. Cost $8, no batts. In a previous thread (which went way off topic, so I started this new one) someone talked about putting foil or mylar behind the tubes. I did it but it's hard to say if output improved. To get the lens off, just carefully pry with a thin knife blade. Comes off quite easily. When putting it back together, make sure you feed the tubes into the holes the leds come out of or it won't go back together.

I think this make a great task or booklight. It's reasonably bright, considering how diffuse the light is. Would make a fantastic tent light. Here's a pick from the previous thread.

 

[The_LED_Museum]

Well... might as well put this train back on the right track...

I just received my test unit, and I must say, if first impressions count for everything I'd flush this baby right down the nearest toliet!

But first impressions are just that - first impressions.

The Folding LED Lantern, as it likes to be called (not "toilet fodder"), actually does an acceptable job of lighting a small room well enough to navigate by. Most of its testing will have to wait until after dark, as this isn't some super bright light saber.

One use I could see for it right away was as a tent light. It hangs up quite nicely with its built-in swinging hook.

It should turn out to be bright enough to use for nighttime reading - as long as you are already at least partially adapted to darkness; for example while camping.
If you are plunged into instant blackness like in a power failure, this might not be the first light you want to reach for.

More later. I can't do a whole lot until after dark.

 

[vcal]

Thanx for those pix, "Sting"

From what it looks like-it needs two more LEDs on the bottom ends of the tubes.
-Maybe rip out the resistor(s) and rewire in series?

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
Thanx for those pix, "Sting"

From what it looks like-it needs two more LEDs on the bottom ends of the tubes.
-Maybe rip out the resistor(s) and rewire in series?<HR></BLOCKQUOTE>

That might work if the light used 5 batteries and not 4.

But maybe there's a way to sneak those LEDs in and wire them parallel to one another (so as to retain the single/double action) and do it that way.

Once I've finished my basic tests, I might take it apart and see if that's a possibility.

 

[vcal]

Craig,
possible solution to that battery snag: using 5-2/3AA cells (w/spacer) in the power pack.
p.s.-I've got Lots of those cells left over, and if you would need any, let me know and I'll give'ya some.

 

[TrevorNasko]

or you could send it to me when your done

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
Craig,
possible solution to that battery snag: using 5-2/3AA cells (w/spacer) in the power pack.
p.s.-I've got Lots of those cells left over, and if you would need any, let me know and I'll give'ya some.

<HR></BLOCKQUOTE>

I've never seen these...thanks!!
So the next obvious question (for someone who doesn't know about this battery) is how would one put 5 (2/3 sized) cells in a battery compartment divided into 4 regular AA holders?!?

???

DO I need to hack up a wooden flagstick & wrap it in kitchen foil to make a dummy battery?

 

[KenBar]

I bought one of these a couple weeks ago on a trip and have tucked it away for a rainy day project. I am going to rip out the 2 resistors and put in a Satcure circuit so I can get some decent life out of it. I will use 2 AA and use the extra space in the battery compartment for the circuit.

I would love to put the LM2621 chip in it but I hate to waste it as I only have one.

It is a really handy traveling flashlight.
My wife liked it is why I got it

LOL

 

[vcal]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Stingmon:
I've never seen these...thanks!!
So the next obvious question (for someone who doesn't know about this battery) is how would one put 5 (2/3 sized) cells in a battery compartment divided into 4 regular AA holders?!?

???

DO I need to hack up a wooden flagstick & wrap it in kitchen foil to make a dummy battery?<HR></BLOCKQUOTE>

That's right, S-P-A-C-E-R-S

When I'm able to pick up one of these lights and definitely do a mod, I'll know what I'm talking about

 

[RonM]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR> It should turn out to be bright enough to use for nighttime reading - as long as you are already at least partially adapted to darkness; for example while camping. <HR></BLOCKQUOTE>
Craig - You're so down on this light, it makes me wonder if yours is working properly. I find no need to for my eyes to be dark adapted for reading and close range work, even with only 1 led on. It even does a nice job of softly lighting a room thanks to its extremely wide beam (almost 180 deg.)

The hinge lets you put the light down and point the light where you need it for task work. Used it last night to fix an outdoor electrical box. Nice even light for work. Total output is probably similar to the Turtlelite II (also a 2 LED light) but spread out over a much larger area.

When you first look at the tubes you get the impression that they are worthless because the are much brighter at one end. However in actual use the light pattern is very even, so they are doing what they need to do.

I'm considering getting a second and removing the whole white reflector assembly. It's easy to do if you unscrew and open up the hinge. This will create a 1 or 2 led flashlight with the leds mounted Eternalight style. The light will be more directional and you'll still be able to aim it thanks to the folding hinge. Anyone know what beamwidth these LEDs are?

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by RonM:

Craig - You're so down on this light, it makes me wonder if yours is working properly. I find no need to for my eyes to be dark adapted for reading and close range work, even with only 1 led on. It even does a nice job of softly lighting a room thanks to its extremely wide beam (almost 180 deg.)

<HR></BLOCKQUOTE>

Once the sun went down, the light seemed to do a good job. I used it after I went to bed whenever I needed to use the can or raid the fridge. I had no trouble reading a magazine with it, and when using it as a walking light, it shines down at your feet with no glare and without ruining your night eyes.

Total emitted light is just a hair less than a Photon III on high. (Test by alternately shining both at the ceiling in a dark room and observing the contents of the room in the reflected light).

So maybe my eyes react differently than yours.... blasted by one too many lasers perhaps. The light itself appears to be working properly.

It's no Arc White, but it does what it was meant to and its batteries will last a heck of a lot longer than those in a real fluorescent lantern.

 

[Chris M.]

I got mine this morning too. I like it- well made and brighter than these posts have led me to believe- perfectly respectable as a reading-light or to provide a soft background glow. The light is pure white, although the 2 LEDs are different colours. One is a cold (ever-so-pinkish) daylight-white and the other is a little yellowish in comparison- they could have matched the 2 diodes which would improve the look but it`s no big deal, this is to be expected of white LEDs.

Here- I`m using it as a keyboard light. Note the usual mess

BTW the missing keys have been removed on purpose- I never use them (insert-overtype mode/popup menu/Caps Lock)and got tired of hitting them by accident while typing and looking up to see something really crazy had happened and wiped out half what I`d typed or it was all in capitals or something. They need to make the keys bigger, then I`ll be OK....

<center>

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This room, after dark, is normally just lit from the glow of a handful of monitors (TV/PC/CCTV) and a string of dim yellow LED xmas lights (that used to be battery powered but now run off a lab power supply)- which is enough for general browsing or tweaking web pages (assuming the screens show light coloured images)- but when I write a lot (like emails or all these posts) I could do with a little more. Even on one "tube" it`s great like this. 2 tubes, obviously, are better still. Actually it seems to be more than twice as bright on 2 as it is on 1, the meter reads 200mcd on one but 700mcd on 2- not sure of the accuracy of my meter at such low levels, it reads in multiples of 100mcd lowest so could have been a high 200 and low 700 for all I know. Remember that peak beam candelas are a function of the beam angle- the overall output isn`t bad for 2 LEDs, it`s just spread out a lot.
Full power easilly lights the room when I hang it up in the middle- not brightly, but enough to see my way around the piled boxes and avoid stepping on trailing 3-pin plugs (which hurts like mad if you don`t see one in the dark, and do so like I did last week- still hurts

).

A nice one for camping or perhaps reading in bed without disturbing others. Nightlight? Current draw is 32.5mA on one led and 63.9 on 2 leds (these may be a few mA too low due to meter losses) and the claimed run time is 100 hours high and 200 hours low. Wonder how close it will get to those figures- anyone know the maths to work it out, assuming Alkaline AAs?
I don`t know how hard it would be to add an external power jack to one of these but if it could be done, a wall-wart could run it after dark in a hallway or bathroom with no worries about recharging or replacing its batteries. Worth looking in to when my testing is done.

 

[**DONOTDELETE**]

Misc-misc-misc-misc-misc...

Re: LM2621 cct... since someone passed on that GREAT caving site -- the guy uses the LM2621 proto cct for one of his caving lights -- I understood how simple it is to sub out a standard 1/4 watt resistor for the SMDs that the proto board uses. That makes it seem a lot easier to mod using that board. He also talks about a step-down cct proto board available -- that would be a natural for replacing the loss-y cct in a PAL... you might get 50 or so hours at full brightness from a 9 v.

I'd love to hear how the satcure cct works -- even if it's not very efficient, I would like to know how other folks make out w/ it.

I'll get a knife and pry the lens cover off mine as soon as I get into my bedroom tonight... and I told my wife I'd be going to sleep early... heh heh heh.

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Chris M.:

Here- I`m using it as a keyboard light. Note the usual mess <HR></BLOCKQUOTE>

You must have gotten a supercharged one.
I can't get anywhere near the results you're getting.

I tried it off to the side, and at the upper left corner.

hmmmm..............

When placed in the center, it works better but then gets in the way of the monitor, and eventually falls over onto the keys as the keyboard slowly worms its way away from the edge of the table.

Chris, I don't see any evidence of a monitor near your keyboard... it must be off to the side someplace?

 

[Chris M.]

Maybe my pic lies a bit- my old VC has a gain control making it more sensitive in subdued light and it was set to full power in that pic. The TV was on but nothing else and I picked a moment of darkness to snap that still-picture. I reckon my camera was just a bit more sensitive than yours and made it look brighter? Still the light output was plenty enough for me- especially after power-off last night. More than enough to find my way to the kitchen too, and I`m half tempted to leave it on the windowsill by the toliet cos it`s a nice soft light that doesn`t dazzle. Hope it won`t fall in

Chris, I don't see any evidence of a monitor near your keyboard... it must be off to the side someplace?



Yep. Over there look. It`s far too big to go anywhere else (got to be near 2 feet total depth!) so I rescued a bit of the old kitchen we had renovated 2 years ago when I got it and it`s stood on top of that ever since...

<center>

</center>

I had the little light perched up on the audio-mixer, just right of central with the keybored but it`s down by the side for now out of harms way. I had it hung in the middle of the room too for a bit, hooked on to a (non-powered) string of C9 lights that are up in here (I know C9s are American Outdoor Xmas lights, and this is the UK, Indoors in August, but it doesn`t bother me!) and it did quite well like that as a dont-trip-over-stuff-in-the-dark light. Definately would make a good tent/camping light, but a shame it`s not waterproof or a bit lighter in weight- 3 AAs would have probably been enough.

 

[RonM]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR> 3 AAs would have probably been enough. <HR></BLOCKQUOTE>
Good point. I'm surprised at the number of flashlights using 4 cells when 3 provide more than the needed voltage. With 4 you just end up throwing away more power via the resistor.

The energizer would be very easy to modify for 3 AA use. The resistor in the hinge assembly would be easy to replace and a dummy battery or a sodered in place wire could be used in the batt compartment. Anyone have a suggestion for the value of the resistor???

 

[Chris M.]

Anyone have a suggestion for the value of the resistor???


Well assuming 30mA per LED and 3.8 volts accross each too- the resistors needed would be 23.3 ohms each, or the nearest equivalent.

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by RonM:

3 AAs would have probably been enough. <HR></BLOCKQUOTE>
Good point. I'm surprised at the number of flashlights using 4 cells when 3 provide more than the needed voltage. With 4 you just end up throwing away more power via the resistor.

The LEDCORP "Belt Light" is a 4-cell light, but they chose to turn it into a 3-cell, bridging the empty battery compartment with the resistor itself. Works out very well, plus in that particular case, makes the light buoyant in water.

Chris: After seeing the "big picture" of your work area, I'm not quite so ashamed of mine anymore.

Great minds think alike - and clutter alike.

 

[Quickbeam]

OK. I follow the calculation above, and am familiar with Ohms law, but I need someone to explain this to me...

It was my understanding that just about any electronic component will only draw as much current (amps) as it needs and that resistance will only change the amount of Voltage that the component receives. The spare Voltage is changed to heat by the resistor. Based on the Nichia specs (20mA draw) and the resistance above (23.3333 ohms) it would seem to me that the LED would not draw 30mA, but instead this resisitance would result in a .466666 Volt difference between Vs (4.5 V) and Vr. So, the LED would receive 4.03333 Volts from the circuit at 20mA, - NOT 3.8V at 30mA - . This would, of course result in the brighter light from the LED, but is pushing it just a touch over specs. Am I correct or is something else going on here with the amperage draw that I am unaware of? (There seems to be a lot of speculation in this area, so while trying not to appear pompus, I'd really appreciate facts, not guesses

).

DP

 

[danno]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR> It was my understanding that just about any electronic component will only draw as much current (amps) as it needs and that resistance will only change the amount of Voltage that the component receives. <HR></BLOCKQUOTE>

I don't think this is true of diodes. The amount of current a diode will draw depends on the voltage across it. If you apply a lot of volts you will get a lot of amps (and fry the LED). If you apply a small voltage you will get virtually no current to flow.

Before you can apply ohm's law to calculate a resistor value, you need to determine the voltage and amperage for which you are designing the circuit. For example, if you know that a Nichia will draw 20 mA at 3.6 volts, then you need a voltage drop of 0.9 volts (assuming three 1.5 volt batteries as a source voltage). Using this voltage drop across the resistor you can calculate the required value of the resistor:

0.9V/.02A = 45 Ohms

The key to figuring out the value of the resistance, however, is knowing the voltage/amperage characteristics of the LED you're using (my figures for the Nichia given above are a guess from prior posts).