Rayovac 2 AA "swivel light" / very easy conversion method

[Silviron]

Anyone seen these before?

I just ran across them recently, and thought they would make a neat LED conversion.

So, I did one- and am very pleased with the way it worked out. For under $16.00 total, I ended up with a cute, versatile little light.

Instructions for the very simple conversion and the results of testing so far are posted here:

http://az123.com/LED/swivelconv/swivelconv.htm

This conversion uses no voltage "pump", regulation or even resistors. A "step-up" circuit would obviously be an improvement, but I don't think it is really necessary. Besides, I wanted to keep this one so simple anyone could do it.

 

[Alan]

I did 3 conversions on another 2AA Rayovac Swivel Light (the original one). for its look, check http://www.rayovac.com/products/flashlights/onelight.php3?sku_num=SL2AA

The one you converted is later (better) version of Swivel Light.
It has the same facetted reflector as the one you converted. I swapped 2AA with 3 N cells. On the last conversion, it took me less than 15 minutes after experience for first 2 conersions.

I got those lights at around $2.00 + another $2.00 for Nichia LED. $4.00 total for each of this converted LED light.

Alan

 

[The_LED_Museum]

There's actually an easier conversion out there.

Go out and pick up one of these:

and stick one of those Sino Union convertor bulbs in it.

Beam from the $3 flashlight with LED mod in place.

Granted, this conversion isn't perfect - but very few are. But it will give you a good household flashlight that lasts forever on one set of "D" cells.

 

[vcal]

Sounds great, Mr.Telephony,-now all I have to do is figure out how to get ahold of one of those Night Pearl bulbs.

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by videocal:
Sounds great, Mr.Telephony,-now all I have to do is figure out how to get ahold of one of those Night Pearl bulbs.

<HR></BLOCKQUOTE>

A "group buy" might be a good option here.
That is, gather everyone who wants one together until the minimum order requirement is met, then someone buys them and distributs the bulbs to everyone else.
Much like what was done with the Starlight 128 flashlights a few weeks back.

$0.02

 

[Quickbeam]

Please excuse my ignorance, but from where does one order Sino Union bulbs? Is there a webpage with specs?

DP

 

[Spidey82]

how does the batt goes in to the 2AA Rayovac Swivel Light ????
3AAA side by side should only be a hair thicker than 2 AA side by side.
wouldn't that be a perfect voltage???
tell me pls.

btw will it be less efficent to use more led, like 3 or 4 leds in them??

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Doug P:
Please excuse my ignorance, but from where does one order Sino Union bulbs? Is there a webpage with specs?

DP<HR></BLOCKQUOTE>

Here is a letter someone else received regarding the purchase of flashlights & Night Pearl bulbs from them.


Dear xxxx
Thank you for your intresting in our products.
During our promotion period of LED flashlight products (May 15,2001 to June 16, 2001), we offer a special price to our clients. Due to commercial reason especial limitation price, the company does not accept the order from individual. We encourage people buy from the company, organization, association ect. The minimum quantity must be 12 PCs (STARLITE-128) per order. We accept the credit card payment from oversea by PAYPAL www.paypal.com.
The minimum charge of UPS www.ups.com is US $37.80 for 0.5kg to each state of America.
Summarize your questions and answers as below:
1: The price of the STARLITE-128 is US $6.50/piece.
2: The price of NPLB-LED BULB is US $4.50/piece.
3: The minimum order is 12 PCs
4: The company does not accept P.O from individual
5: The company accept payment from PAYPAL
6: The shipping cost by UPS is $37.80-0.5kg
7: The average shipping cost of STARLITE-128 is US $37.8/12=$3.15

Best regards
SINO UNION TECHNOLOGY LTD
Mr. Horacce Lee
[email protected]


The website is at http://www.sinounion.com.hk

 

[Silviron]

Hey Spidey! Cool thinking

Yes three AAAs fit pretty nicely. You would have to make a battery pack to make it work--

-
Tabbed cells and pretty thin heat shrink (it is pretty snug with three AAAs in there, but the contacts on the bulb end work out OK so no need for a modification there. (Actually, you could probably get away without using heat shrink...)

Of course with the AAAs being shorter than the AAs, the bottom contacts wouldn't work even if you "re-configured" them (that's why I don't see any practical alternative to making a pack with tabbed cells).

But there is just about exactly enough room to fit in a power jack, so you can just stick it on a recharger since you would want to use NiCds or NIMHs to get your 3.6 V. anyway.

Making the battery pack would cost just about the same as the AA Lithiums, so the initial cost of the project would be about the same (if you have a handy charger for the 3.6V around).

Your initial brightness would probably be a bit higher than with the 2 lithiums and last a little longer maybe, although the two lithiums will probably provide usable light longer- (I'm just guessing, but pretty sure about it)

My original test of one LED on 2 AA Lithiums has been burning continuously for 12 days now and is still bright enough to easily find your way around a pitch dark house or out of a cave; Plenty of light to read 1 inch tall letters at 10 feet and at least show the shape of things at 20 ft. Also plenty of light to do close up work. (I'm REAL impressed with this configuration so far

I ordered one of the light meters that was the subject of one of the other threads here, so in the not too distant future I'll be able to be more precise about how much light is being output at various stages, but for now...

Nonetheless, I like your idea! I think I'll go get another swivel light and make a rechargable out of it!

Putting more LEDs in would give more light, it would also reduce battery life. It would also be kind of a hassle- you would have to modify the LED mounting and the reflector to the point that it would kind of turn this into a major project.

OH, and if anyone else gets a wild idea about stuffing other kinds of non-AA batteries in there- a 9V will fit with a little modification, and the contacts are just in the right place too. Not sure if this information is of any value, but if you were wondering...

 

[Quickbeam]

Silviron:

OK, so far so good. I'm kind of new to the electronics thing, so i'm stuck on a problem. On your website for the conversion, you state that the Nichia LEDs can't handle over 4 volts, but my Photon drives it's white Nichia LED at 6 volts (2x3v 2016). What am I missing here? Is there something going on with the amperage output of the smaller batteries? Sorry for the newbie questions....

(I'd like to try your conversion with a 9v, but I guess I have a bit to learn first...)

 

[Spidey82]

how abt 4 leds, two in parallel and two in series.
think in that way it could take 9V.


i was thinking intially that u could tape 3 AAs together and wired the accordingly.
and have two contact points.
or if there is anyway to make a battery pack would be great.

could that be done to a 2AA holder??

 

[snakebite]

if going rechargeable get prismatic cells.
the ones i have are the same length as a aa cell but are flat.got mine at murphys surplus in CA

 

[X-CalBR8]

Doug P: In answer your question about the Photon using 6volts, the way it gets away with this (from what I've heard others say) is that it only operates at 6volts for a very short time and then drops down a little. Also, the button batteries are so small that they are incapable of sending enough current to fry the LED like other, larger batteries would. Take it from me, if you try to push a Nichia White at 6volts from a larger battery, you had better have some serious heat sinking ability set up because it gets hot quick! It is the heat that destroys the LED. (This leads to issues of thermal run away, which is a whole another discussion by itself). If you can keep the LED cool, then you can run one at 6volts. Although I believe that even with a very good heat sink that you would still greatly shorten the life of the LED from the rated 10year life though because the die inside the LED would have a hard time keeping cool enough.

 

[Quickbeam]

Thanks. I wasn't actually going to try running the LED at 6v, but I was thinking more like the 4.5v you would get from 3 AAA cells that fit in the case of the flashlight as shown above. Apparently this would still need a resistor, so I may as well just look at a 9v conversion. OK, now for stupid newbie question #2. How do I figure out what resistor value to use? The RadShack salesmen are next to useless. Is there a webpage out there that teaches beginning electronics that anyone could recommend?

DP

 

[Silviron]

X-Cal covered the voltage thing (Thanks!), so I guess I don't need to go there.

Really- I was just kidding about sticking a 9V in there- It would fit with some modification, but would be more trouble than it is worth.

A battery holder wouldn't work (no room for it.- You have to make a pack- get three tabbed AAAs and solder them in series, with enough "slack" to "fold" up the batteries and fit them in the case. (You would have to use a little bit of wire between each solder joint as the tabs won't be long enough. Simple.

If I do convert another to 3 AAA rechargable I'll post some pictures.

As far as making LED lights to use 9V batteries- I have made three different ones "from scratch" in project cases- One with 5 series LEDs that run off of two series connected "heavy duty" or alkaline 9V batts. (18 V total) No resistors needed! Another with 10 LEDs (in 2 Parallel series of 5 LEDs) They both are great- Last longer than I would have expected (5 days + of "usable" light, Several hours of "BRIGHT") on the 5 LED unit.

Also made one using 4 LEDs running off of 2 rechargable 9V (7.2 actual V) batts. You can do this configuration as straight series- (4 series LEDs 2 series batteries for 14.4V or, you can do 2 series LEDs off of each individual battery- {gives you a redundant system

But requires 2 switches

}

The one I did is straight 14.4 V series- It is very bright (does run hot) but battery life isn't as good as I hoped {2-3 hours at good brightness, a few more at moderate brightness and tapers off to really dim in 10-12 hrs}. I don't know if it is just the capacity of the batteries or if I'm not getting a good charge- I'm not using a regular NiCd charger- just a 15V "Wall Wart" transformer plugged into a jack on the light.

For whatever it is worth---

 

[X-CalBR8]

Doug P: If you use a 9 volt battery, then you would need to used 2 LEDs in series (not parallel) in order to send 4 volts to each and then you would need a resistor to drop the extra volt. Although if you wanted to try it, you could probably get away with not using a resistor at all and just send 4.5volts to each LED. A lot of people run their LEDs at 4.5volts and get away with it (me for one

). By using the full power of the battery, you will have a significantly brighter light, but you will shorten the LEDs life somewhat by pushing it so hard. Considering that LEDs will last for 10 years of constant use when not overdriven, I wouldn't be too worried about shortening that by a few years.

I've not made a LED light powered by a 9volt yet, but it's such a small battery that it's internal resistance would probably (I think) keep the LEDs from running away too badly. Just to be on the safe side, you may want to put a heat sink to carry away the heat from the negative leads on the LEDs. I used a Penny on my last mod and it worked very well. Remember that it has to be a pre-1982 Penny in order to get a solid copper one. After that it is copper plated zinc. Just drill a hole through the penny the same diameter as the lead on the LED then solder it on. I plan to use silver epoxy on my next one to keep from heating the LED too badly when connecting it to the Penny. I had rather use a heatsink and have a brighter light than use a resistor and burn up power to no real use. If you still decide to use a resistor, I would use a 10-Ohm and it should work fine and be at a very safe range. 10 Ohms is a very common resistor value and any electronics shop such as Radio Shack will definitely have them.

The formula that you are looking for is: Resistor Value = Supply Voltage - LED Voltage / Desired LED Current in Amps.

In this case, Supply Voltage = 9volts, LED Voltage = 4volts x 2= 8Volts and the desired LED Current in Amps would = .040 x 2 = .08amps. Now remember that all of these calculations take into account that you would use 2 LEDs in series, NOT ONE SINGLE LED. This is very important to remember. If you were to do the calculations to use a 9volt battery with a single LED and a resistor to take up the rest of the voltage, then you would waste over half of the batteries power just turning electricity to heat via the resistor (that's what resistors do). I hope this info helps and good luck with your mod. BTW, I couldn't agree more about your assesment of Radio Shack salesmen (and especially saleswomen). LOL.

 

[danno]

Here's a web page that outlines how to compute the proper resistor value:
http://www.caving.org.uk/gear/led/wiring.html

 

[Silviron]

OK- I did the rechargable 3AAA conversion. It is definitely a more difficult project than I originally conceived for this light, but it works.

I took pictures during this conversion and will try to get the illustrated instructions posted on my LED web page in the next day or two. Will post a link when I get it done.

This light is a bit brighter to start with than the 2 AA Lithium conversion- Haven't done any longevity tests on it yet, but am not expecting anything exciting.

Did figure out a couple of shortcuts that would have saved a little time on the first project, so will ammend that one too.

Also, if you want to do one of these lights and are a cheapskate like me, shop around- I found the light at Fry's Electronics a dollar cheaper than at Lowe's. If Wal-Mart carries them they will probably be even less there.

I notice that there is a 7 LED conversion of the larger D cell swivel light up on Ebay. I looked at one of them (non-converted)yesterday: Big, bulky light with plenty of room to do mods if you want to carry something that size around.