# 5mm LED battery drainer



## datiLED (Jun 13, 2010)

I hate to throw away batteries that have any juice in them at all. Of course, even a weak battery can power an LED if the driver is efficient. 

Here is my take on a Joule Thief, that drains my batteries before disposal. The pictures speak for themselves.


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## Lynx_Arc (Jun 13, 2010)

I use several things to drain batteries, I have a dorcy 2AA 40 lumen LED light that will work down to about 1v I can pull the head off and use it like a floodlight, and I use the LED and circuit from a luxeon headlamp wired to a 4AA battery holder and a variable resistor to light my keyboard up that drains them to zero volts using junk nimh to make up to 3 AA/AAAs. 5mm are ok but the focused beam makes them less useful for light output when they dim too much for ceiling bounce.
also a minimag 10mm LED from niteize works down to half a volt I have used them on a single D cell to run for days and days with just a bent paperclip.


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## datiLED (Jun 13, 2010)

I didn't know that the NiteIze board could drain a single cell. I could have picked up a few of those at Home Depot a while back for under $4 each.

I didn't mention that there are magnets on the battery side of the circuit boards. I used conductive epoxy to adhere them to the boards. While it is probably overkill, I also made a PCB for the Joule Thief. I prefer to use SMD coponents, and it made for an easy build.


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## csshih (Jun 13, 2010)

wow, that is some very good work with the pcb and magnets... looks very professional.. interested in selling one?


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## ^^Nova^^ (Jun 13, 2010)

Or 2? They look wonderfully made. I love the magnet idea.

Cheers,
Nova


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## Lynx_Arc (Jun 13, 2010)

datiLED said:


> I didn't know that the NiteIze board could drain a single cell. I could have picked up a few of those at Home Depot a while back for under $4 each.
> 
> I didn't mention that there are magnets on the battery side of the circuit boards. I used conductive epoxy to adhere them to the boards. While it is probably overkill, I also made a PCB for the Joule Thief. I prefer to use SMD coponents, and it made for an easy build.



I took one and transplanted it into a rayovac keychain light and it works fine off 1AAA.


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## JimF (Jun 13, 2010)

Why is draining a battery completely before disposal so important. I am not being critical. I just don't understand the concept. 
Thanks,
Jim


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## Lynx_Arc (Jun 13, 2010)

JimF said:


> Why is draining a battery completely before disposal so important. I am not being critical. I just don't understand the concept.
> Thanks,
> Jim


before the advent of LEDs when batteries hit 1.1v the lights dimmed to unusable levels. There are still some lights and devices that quit working when batteries hit 1.1v or so. at low power levels that can drive an LED for 10-20 or more hours. 9v batteries can run LEDs for a long time as smoke detectors complain when the battery gets below 7v or so. It is fun to drain all the power out of a battery as you cannot do the same with rechargeable batteries.


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## dom (Jun 13, 2010)

It's not so much draining the battery but the light
you get from it.(handy nightlight or for other purpose)

Cheers
Dom


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## dealgrabber2002 (Jun 15, 2010)

oh... i like one...


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## nein166 (Jun 16, 2010)

That is the nicest joule thief build I've seen so clean and tight
And it tailstands 
Blows my Astroboy out of the water




He was a McD toy, Wired him up with the coil under the base.
Magnet to hold a AA on the base. Copper tab under his hand.
Push a button in his back and the arm lifts, release and it clamps the AA
Green LuxIII in the foot, runs for a few days

Could you put together a parts list and maybe a board design?
How about selling kits?


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## TorchBoy (Jun 16, 2010)

Nice work datiLED and nein166.


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## [email protected] (Jun 16, 2010)

I don't have many primary cells to drain with the exception of the odd CR123a/AA cell, nice work guys very environmentally repsonsible of you (minimizing waste)! :thumbsup:


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## daf3m (Jun 16, 2010)

nein166 said:


> That is the nicest joule thief build I've seen so clean and tight
> And it tailstands
> Blows my Astroboy out of the water
> 
> ...



cool!!!!!


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## datiLED (Jun 16, 2010)

^^Nova^^ said:


> Or 2? They look wonderfully made. I love the magnet idea.
> 
> Cheers,
> Nova


Thanks. I have made dozens of different LED boards, but this was my first design with the magnets. This is actually the Supercharged Joule Thief (high efficiency version) from a cool electronics e-blog site.



JimF said:


> Why is draining a battery completely before disposal so important. I am not being critical. I just don't understand the concept.
> Thanks,
> Jim


It is mostly just me being OCD. I hate to throw out half dead batteries. But, it is also a good opportulity for me to make little gadgets to produce light. I love designing, etching and building circuit boards for LED drivers (and guitar effects). So when I see a cool circuit that I think would be a good build, I draw a PCB in AutoCAD, make a transfer, etch it and make a prototype. If it works, then I refine the design until I am happy with it. If not, then I find out what I did wrong. So basically, it is a hobby for me.



dealgrabber2002 said:


> oh... i like one...


 I might make a few to sell, to cover the cost of the conductive epoxy and other parts that I had to buy. 



nein166 said:


> That is the nicest joule thief build I've seen so clean and tight
> And it tailstands
> Blows my Astroboy out of the water
> 
> ...


 I love your Astroboy! That is really cool. :thumbsup:

Making a kit would be fairly easy. But, the circuit is built with SMT components, and requires a fine tip soldering station, or iron. I have the board documentation ready to go, and a clearly labeled blow-up of the populated board (which makes it easy for me to build). The inductor is wound by hand, and the polarity must be correct for the circuit to work. I could do a kit form of the thing for just a little over my cost. I had to buy the parts to make about 20, or 25 of them just so that I could make the one that you see in this thread. :shakehead



TorchBoy said:


> Nice work datiLED and nein166.


 
Thank you. I agree... Astroboy is cool.


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## nein166 (Jun 16, 2010)

That Conductive epoxy is interesting stuff, but what we need are electroplated steel retaining clips that can be soldered to a PCB and hold the magnets.
Astroboy was a fun weekend project that I made, like you said hand wound coil and I just used discrete components and dead-bugged them together. I salvage components off of PC (and Mac) mainboards (great source for toroids), and other garbage.


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## maxspeeds (Jun 16, 2010)

This is a really cool design. I especially love the magnets so that various battery sizes can be used. 

If you decide to make more to sell, please shoot me a PM. I'm definitely interested . I also try not to throw away batteries with any juice as I'm OCD about wasting everything from water to household electricity.


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## dealgrabber2002 (Jun 16, 2010)

Please let me know when you have a few to sell. 

I wonder what's the runtime like on a fresh alky, any idea?


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## datiLED (Jun 16, 2010)

dealgrabber2002 said:


> I wonder what's the runtime like on a fresh alky, any idea?


 
_Days_. I got 3+ days from a partially used alkaline cell (1.2V). It wouldn't work in my digital camera, but worked very well with the LED driver.


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## Lynx_Arc (Jun 16, 2010)

I just took a 9v battery drainer and hooked it to two 9v batteries I have drained in series to drain them some more.


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## csshih (Jun 16, 2010)

maxspeeds said:


> If you decide to make more to sell, please shoot me a PM. I'm definitely interested . I also try not to throw away batteries with any juice as I'm OCD about wasting everything from water to household electricity.



same! send me a PM if you wish to sell one. oo:


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## dealgrabber2002 (Jun 17, 2010)

Please shoot me a PM when ready to sell them. I LOVE long runtime.

Does this only work for AA batteries?


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## Lynx_Arc (Jun 17, 2010)

dealgrabber2002 said:


> Please shoot me a PM when ready to sell them. I LOVE long runtime.
> 
> Does this only work for AA batteries?



should work for any 1.5v battery I would think and perhaps even severely drained 123 primaries (2v or less)


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## dealgrabber2002 (Jun 17, 2010)

Lynx_Arc said:


> should work for any 1.5v battery I would think and perhaps even severely drained 123 primaries (2v or less)



I hope it can drain cr123 or maybe C or D cells.. imagine the runtime on a D cell.


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## Lynx_Arc (Jun 17, 2010)

dealgrabber2002 said:


> I hope it can drain cr123 or maybe C or D cells.. imagine the runtime on a D cell.



I expect it would drain 123s that are almost fully dead as they would sag under the load but 123 cells that have even 20% left in them may have too much voltage for the circuit would be my guess.


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## dealgrabber2002 (Jun 17, 2010)

Lynx_Arc said:


> I expect it would drain 123s that are almost fully dead as they would sag under the load but 123 cells that have even 20% left in them may have too much voltage for the circuit would be my guess.


 
Oh, sorry. I am very limited when it comes to voltage/circuit and almost all technical stuffs. I thought it can be use with a new cell or almost dead cell.

Something like the MC II from Milkyspit.


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## Lynx_Arc (Jun 17, 2010)

dealgrabber2002 said:


> Oh, sorry. I am very limited when it comes to voltage/circuit and almost all technical stuffs. I thought it can be use with a new cell or almost dead cell.
> 
> Something like the MC II from Milkyspit.



I am guessing the boost circuit is designed for an input of about 1.5v while a 123 cell has a voltage (new) of about 3-3.2v which is way too much voltage. It would be like putting 2AA cells in a 1AA light , you can only do that when both cells are half dead so together they equal only 1 cell instead of 2. I would just figure it wont drain 123 cells but if you had a 123 cell drainer it may be able to finish them off after it quits working.


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## aurum (Jun 17, 2010)

Please shoot me a PM when ready to sell them. I LOVE long runtime.


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## alantch (Jun 18, 2010)

Would love to have one that'll work for 123 cells as well. Let me know once you have them ready for sale. I have lots of exhausted cells that can be put to good use with this gadget.


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## dealgrabber2002 (Jun 23, 2010)

Does this work with fresh batteries? And what is the max. voltage?


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## nein166 (Sep 1, 2010)

Looking forward to picking up a couple of these up when you make them datiLED, saving my dead batteries


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## Phaserburn (Sep 1, 2010)

One of the easiest AA battery drainers I love is a stock, headless incan minimag; no circuits required. Just plug your 5mm led of choice in, and it will run a looooong time on "dead" cells. I sand the leds for a 180 degree even flood. An amber led like this while the MM is standing in it's head for candle mode works well. Extremely easy to mix and match cells, colors, etc.


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## Lynx_Arc (Sep 1, 2010)

Phaserburn said:


> One of the easiest AA battery drainers I love is a stock, headless incan minimag; no circuits required. Just plug your 5mm led of choice in, and it will run a looooong time on "dead" cells. I sand the leds for a 180 degree even flood. An amber led like this while the MM is standing in it's head for candle mode works well. Extremely easy to mix and match cells, colors, etc.



I have a 2AAA incan I put a newer cree 5mm LED in that I use as a nightlight off nimh it can run for weeks without changing a battery. If you could easily get a 3AA incan minimag and make a variable resistor tail cap you would be able to drain batteries even better.


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## Phaserburn (Sep 1, 2010)

Actually, even drained alkalines run many weeks because the low voltage only sends a trickle of current to the led, giving decent brightness and prolonged runtimes, as I'm sure you know. Reds and ambers work especially well with their lower vfs.


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## Illum (Sep 1, 2010)




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## alantch (Oct 3, 2010)

I got an SJT circuit recently from datiLED and this was what I came up with over the weekend, all with parts I could find around the house.


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## sidewindsixty9 (Apr 4, 2011)

Actually for the past 6 months ive had a green led light on constantly on my window ledge out towards the porch its visible and shines a small spot
powering it is a 3volt battery of the type you find in a watch
its not full brightness just enough to see and greet visitors from 10 feet away and glows fine.. i cant explain exactly why but i think its the low current and recharge rate of that effect


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