Joule Thief Goes Legit

yes ha ha very funny.

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John Devereux

Miniaturization is only necessary for using same size battery. Someone can probably come up with a down-sized converter (i.e. using AAA for AA). I know, i know, you are going to tell me it's already been done.

Maybe I need to patent the idea that a battery can be made with such a circuit built in to give 799% longer battery life (you loose a tiny bit by adding the circuit). This won't be limited to devices with extra space in the battery compartment.

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Rick

Well, it's legitimate in that it will be making money soon:

It's a Joule thief built into a stainless steel and plastic sleeve that fits over a 1.5V cell. According to the patent holder, it can extend the useful life of that cell by 800%:

Notice that a specific Joule thief circuit isn't what's being patented; it's the idea of putting any circuit that does what a Joule thief does into a sleeve that fits over a battery.

800% looks a tad optimistic (depends on the power draw obviously) but I still will buy a metric crapload of them until the battery mfgrs eventually break down and get licenses to build them into each battery they sell. It's the only sensible thing for them to do once they put two facts together; the inventor says they'll sell for ~US$2.50 each, and we will be buying one-eighth (whatever) of the batteries we used to, killing the battery folks' profits. If a battery lasts that much longer, we'll probably be willing to pay more per, but three or more bucks for a damned AA cell is just ridiculous. I'm guessing the inventor is overly pessimistic and serious mass production can cut the cost per thief.

Fun fact; the patent holder's space was *broken into* and material specific to the patent was stolen but the patent had already been quietly obtained.

Mark L. Fergerson ==========================================================================================================

I want two NOW for AAA batteries :-). I use a fingertip pulse-oximeter data logger each night that runs on 2 AAA batteries and has a low battery shutdown at 1.25 volts per cell. A pair of alkalines will only last about

24 hours so I bought some NiMH's that have enough energy to run for at least 24 or 36 hours but because of the internal shutdown they only go about 12 hours which really means one night of 7-8 hours and then I have to recharge them when they are really only about 30% down. So it's a daily morning ritual, take 2 cells off the charger, put them in the logger for use that night, put the low cells in the charger, and repeat each day. I'm tired of this, and it's not good for the NiMH's to be short cycled either, I have to deep discharge them every now and then to keep their capacity up.

One caveat about the batteriser, it will render any battery level indicator in a device useless since it will show 100% until the cells hit .6 V and the output drops to zero suddenly.

----- Regards, Carl Ijames carl.ijames aat deletethis verizon dott net

Ooh, very good point. No real way to address that unless the "real" terminal is brought out for metering.

Mark L. Fergerson

Too late, I already blabbed it, so it's "prior art". Damnit.

Mark L. Fergerson

Most things that use batteries will run until the batteries are 99% done. So no saving there. If there's a piece of equipment that will stop working when the cell voltage is only 1.4V then its design is flawed... It should use at least 3 cells... This should have been posted on April

1st... Duracell can breathe easy :)

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Sigh. Let's see if it works on paper. I'll start with the best case scenario:

The discharge curve for a AA alkaline battery looks something like this [1]. I'll use the Ray-o-Vac Max (green) line. According to the PC World article, the mythical device quits when the voltage drops to 1.35v. Assuming a constant discharge current, the power (watts) available is the area under the curve between full charge at the left, to wherever the mythical device cuts out. Total available power is the area under the entire curve: The area bounded by the red box is that available power until the battery voltage drops to 1.35v. The area in the green box is what's left unused, until the battery voltage drops to 0.5v. The green box area seems about 8 times larger than the red area, which means that for a AA alkaline battery at 1A discharge, one might actually get 8 times the battery capacity with the joule thief.

However, let's try it for a rechargeable battery, such as a NiMH AA battery, which would be worst case. I'll use my own test curve. This is a series of 1C (2.3A) discharges of an Energizer 2300ma-hr cell: Notice how flat the curve is. Usually, the device this powers gives up when the cell voltage drops to about 1.0v. If I draw the same boxes as I did with the alkaline cell, I would guess(tm) that about

90% of the battery power is used before it gets to 1.0v with maybe 10% remaining. If you're luck, you might squeeze an additional 10% more power out of the cell. It's much the same for NiCd and LiIon cells that also have flat discharge curves.

Bottom line: Probably a usable idea for alkaline batteries. Carbon-zinc might also work. However, it's worthless for NiCd, NiMH, and LiIon. They don't make lead-acid batteries in size AA, so that's out.

[1] Scraped from:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

It's not a U.S. patent -- it is a pending U.S. patent application. It has not issued as a U.S. patent.

You can check the status by going to:

and searching for application number 13/236,436 to see the current status of the application.

Executive summary: the fun hasn't really started yet as far as prosecution on the merits goes.

Details:

Current status shows they received a restriction requirement on

2015/4/8. The examiner is telling them they've got more than one species, and they need to restrict prosecution to one species.

Looking at the restriction requirement, the examiner says they've got three species -- the battery sleeve of fig 2, the battery sleeve of fig

3, and the battery sleeve of fig 4. The examiner is telling them to pick one for prosecution. They can argue with the examiner on this; well, they can try, but this is an argument the examiner usually wins.

Looking at the file history, they've submitted a lot of documents, and also revised the claims after the thing was printed.

They're still a ways away from arguing this thing on the merits, let alone having an issued U.S. patent.

** That is not one bit likely. ** That is not one bit likely either. ** So it's a Pie in the Sky patent ... ** ROTFL - it reeks of scam.

** Cripes you are gullible.

The whole thing looks exactly like "vapourware" - all hype, no specs.

Stuff like this appears in the media regularly, claiming to do the impossible and fix a crying need that simply does not exist.

.... Phil

The 800% figure depends on the device being powered having an unreasonably high voltage at which it quits, such that it leaves most of the energy unused.

The patent says that some do - and that's probably true - but I'd be surprised if they represented a large proportion of devices. After all, a device that chews through batteries unnecessarily fast is likely to get bad reviews.

Looking at figure 7 in the patent, a device that accepts 1V per cell would use most of the energy in the cell, and the Batteriser would provide little benefit.

Indeed, pumping the voltage above what the device needs is just wasting energy in the device, and the Batteriser itself consumes some.

My overall take on this is the Batteriser could be legally sold, provided the claims are couched in careful terms, but that for most devices it will prove to be less than worthless.

Sylvia.

On a sunny day (Tue, 2 Jun 2015 15:05:46 -0400) it happened "Carl Ijames" wrote in :

You can buy these, one 3.2 V and one dummy in series:

Although I bought from a different seller, I can testify that these last ++ hours in my wireless keyboard. You can charge them from a voltage and current limited lab supply for example. Very low self discharge too. Gives you the equivalent of 1.6 V per cell.

I do not believe in that joule thief invention, interference (radio), high current (camera), all come into play. And for something as simple as a flashlight it does not matter if it gets a bit weaker, good warning to replace or re-charge. For the uA range (temp meter etc) it makes no difference and may actually be worse. What uses exactly 50 mA ? I dunno.

fits over a 1.5V cell. According to the patent holder, it can extend the u seful life of that cell by 800%:

it's the idea of putting any circuit that does what a Joule thief does int o a sleeve that fits over a battery.

still will buy a metric crapload of them until the battery mfgrs eventuall y break down and get licenses to build them into each battery they sell. It 's the only sensible thing for them to do once they put two facts together; the inventor says they'll sell for ~US$2.50 each, and we will be buying on e-eighth (whatever) of the batteries we used to, killing the battery folks' profits. If a battery lasts that much longer, we'll probably be willing to pay more per, but three or more bucks for a damned AA cell is just ridicul ous. I'm guessing the inventor is overly pessimistic and serious mass produ ction can cut the cost per thief.

ific to the patent was stolen but the patent had already been quietly obtai ned.

Where'd you see it was a Joule thief (blocking oscillator boost topology)? I didn't see it.

Pretty tough to make that

Oops. Replace the "power (watts)" with "energy (joules)" in several places in my rant. Sorry(tm).

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

I'm not sure it matters. You switch thresholds from 1.35 V for alkalines to 1.0 V for rechargables. That is pretty unrealistic. I have a device that uses AAs and does not understand NiMH. They work but I get a small percentage of the "juice" available. (notice my use of the vernacular to avoid the entire issue of technical correctness, joules vs. watts vs. mAHrs)

The point is that your conclusion does not follow from a realistic comparison.

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Rick

Correct. Each battery chemistry has its own discharge characteristic. The concept behind the jewel thief works best with a battery chemistry that does NOT produce a fairly constant voltage during discharge, which would be an alkaline cell. With my switch in threshold voltages, I'm assuming that the jewel thief vendor will have different models for different cell chemistries, or possibly a settable threshold.

I don't believe the inventor claimed that his device would magically convert battery chemistry and characteristics or work with every type of battery chemistry.

True and my comments are not really a perfect comparison. They're an attempt to determine how it would work using a given chemistry. I selected two such chemistries, alkaline and NiMH. It works with alkaline if you accept the 1.35v assumption in the PC World article, and doesn't work with with NiMH where the the 1.35v assumption in the article is unworkable. I then changed the 1.35v threshold to 1.0v to accomodate the change in chemistry.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Irrelevant. The device you use the batteries in knows nothing about the chemistry.

You are making inconsistent assumptions about the devices. You are focusing on unrealistic scenarios.

You can make all the assumptions you wish. They don't justify any expectations in the real world.

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Rick

I didn't see it.

Eh, SOT-523s (or smaller!) mounted on FPC would do.

Magnetics would be hard, but perhaps there are enough 0402 range inductors to handle the energy.

It would be useful on a conventional incandescent flashlight, where the light intensity and light quality steadily degrade over time. Or a cheapo LED, where the intensity decays without the warning of color.

Anything with a battery controller, assuming it's functional down to voltages suitable for the chemistry (for alkalines, 0.75V is the usual cutoff, which would also be more than enough for NiCd/NiMH), wouldn't have any use for something like this.

I wonder if it's charge tolerant, in case a dummy leaves it on the cell and puts the cell in a charger.

Tim

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Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: http://seventransistorlabs.com

The device is presumably design for a specific type of battery. Plugging alkaline AA batteries into my ancient Canon A30 camera blew it up because the camera was specifically designed for NiCd and NiMH batteries, which have a lower voltage. There are many devices that have built in DC-DC converters that will run over a wide range of battery types, but then, such a device would not need the joule thief.

Given only the information in the PC World article and the patent application, that's about all I can do. One thing we do agree upon is that the piggy back device will need to know something about the battery chemistry in order to (allegedly) function.

I think I made a tolerable case that it might work with alkaline cells if the device cut off at 1.35V. I also demonstrated how it would not work with NiMH cells. I don't see a problem with what I wrote. I will admit to making assumption, but that's typical when I try to convert the usual incoherent marketing gibberish, as interpreted by a popular magazine, into something digestible by engineers accustomed to numbers, test results, calculations, and specifics. Since I don't work for the designer of the joule thief, you'll just have to settle for my assumptions, assertions, conjecture, and anything else you care to accuse me of using.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558