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Death by 9V battery design challenge

Hi all,

Just wondered if it is possible to come up with a circuit which would enable a single PP3 9V battery such as this:

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to function as the power source for a taser? I'm sure proprietary tasers are manufactured with far more suitable batteries than a PP3 and it wouldn't be hard to come up with a near- lethal/lethal design if a significantly higher capacity battery were permissible. But there's no challenge in that. This is just a bit of fun (remember when we had fun?). If you had to come up with a design concept for a taser-like weapon which HAD to run from a PP3, how would you go about it? Given that you would probably incorporate some sort of switcher, which topology and ancillary concepts would you choose to most efficiently convert the *very* limited amount of energy these cells contain into something that could kill or disable an assailant? I'm not looking for a specific circuit here; I'm not planning on building one; it's essentially just a thought experiment - a fun conceptual challenge - to establish if it could be done AT ALL with such limited power, and if so - how?

Your thoughts invited!

CD.

Reply to
Cursitor Doom
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The best way to use the energy in a 9V to kill or disable an assailant would be to use it to accelerate a projectile, probably.

Reply to
bitrex

Where is the challenge?

NT

Reply to
tabbypurr

According to this page:

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an electric shock of 50 J can be fatal.

According to Wikipedia

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one of these batteries has a capacity around 500 mAh. At a nominal 9 V, that's over

16 kJ.

If you could use the energy to charge a large capacitor to a high voltage, you could perfectly well make death trap.

--
RoRo
Reply to
Robert Roland

Ballpark thinking stuff:

An alkaline 1604A has a capacity of 565 mAH. The lithium 1604LC variant is about twice that.

565 mA * 9 V * 3600 sec = 18306 Joule

Tasers, cattle prods and other electro-torture devices are claimed to deliver between 1 and 10 Joule/shot.

--
Grizzly H.
Reply to
mixed nuts

Mostly if not entirely in the battery's internal resistance I would imagine. How would *you* deal with it if you're so smart?

Reply to
Julian Barnes

A 9V alkaline battery stores ballpark 18 kilojoules of energy. That is a way-lethal amount. Use it to charge up a lot of electrolytic caps to a kilovolt or so and grab the leads.

I have papers here that consider anything above 10 j to be dangerous.

Killing people is just a bit of fun?

Reply to
John Larkin

A stab in the dark here. Determine the 'high voltage' by multiplying a 'typical' fatal mA level by a 'typical' figure for skin resistance and hope for the worst. :)

Reply to
Julian Barnes

Den fredag den 2. oktober 2015 kl. 23.00.02 UTC+2 skrev John Larkin:

a defibrillator is something like 200J

I guy I know used to work on those, afaiu if you got shocked while working on one the standard procedure was 24hour observation

-Lasse

Reply to
Lasse Langwadt Christensen

CD-

How much energy is stored in the battery? Suppose it holds one Ampere-Hour. That is one Joule per Second times 3600 Seconds, or 3600 Joules.

Now, how much energy is required to operate your taser? If it is less than 3600 Joules, then such a battery could be used. You would need to figure out how to transform the energy to a useful form. Perhaps an oscillator and a voltage multiplier, with a rectifier to charge a capacitor to a high DC voltage?

Fred

Reply to
Fred McKenzie

Of course if I can have _two_ 9V batteries, I can make a couple of megatons' worth of explosion, and erase a small city. Oh, of course one does have to be antimatter. ;)

Cheers

Phil Hobbs

Reply to
Phil Hobbs

OK, I mixed up Watts and Amps! And someone else beat me to it. That is

9 Joules per second times 3600 Seconds, or 32,400 Joules. (Perhaps a lithium battery would be required for that much capacity.)

Fred

Reply to
Fred McKenzie

Urgh. I picked the PP3 off the top of my head. If it's a piece of cake, then how about a 1.5V AA battery instead? Or perhaps a button cell? Now

*that* would be something!

Come off it, John. You know perfectly well I'm referring to the design challenge.

Reply to
Cursitor Doom

My wife managed to almost set herself on fire with an alkaline 9V battery. She threw it in a coat pocket with some coins in it, and discovered it when it started smelling like smoke! Getting the hot battery out of the pocket without getting burned was tricky.

Anyway, these batteries are not able to deliver their full energy content in a short time, but still can deliver a fair bit of energy in a few seconds.

Jon

Reply to
Jon Elson

There's enough energy in a 9v alkaline battery to accelerate it to 780 m/sec, or 2600 fps. About 9 times the energy in an AK47 round.

That would hurt.

Reply to
John Larkin

You're just being silly, no? Sure it'd make for an awesome explosion if all the mass of the battery were to be converted into energy but that's never going to happen in the real world.

Reply to
Cursitor Doom

Luxury. A CR2032 (~250mAH), at 2.7kJ, holds more than enough.

"Watch the coin cell, Johnny!" "Aw gee, Mom..."

Cheers, James Arthur

Reply to
dagmargoodboat

I read once that a fully LiIon 18650 holds a great deal more energy than a hand grenade. That makes a thousand or so perfect for cars.

"Sir, your suici^H^H^H^H^H^HTesla is ready."

Cheers, James

Reply to
dagmargoodboat

d

-PP3-

come

om a

orate

ou

gy

lding

d

ne

a hand

handgranate is ~700KJ, roughly the same 1 kg LiIon

or 15 grams of gasoline

-Lasse

Reply to
Lasse Langwadt Christensen

No need for aunti-matter. Just short the terminals and you'll have a nice small chemical explosion: There's a small chance that the 9v battery was a counterfeit, but I'm not certain as the remains were recycled before I had a chance to dig deeper.

9v batteries suck. In about 1998, I helped redesign a product that ran on 9v alkaline batteries. My task was to make the circuit tolerant of all the problems presented by the 9v battery, such as high ESR, wide voltage variations[1], bulging packages, intermittent terminals, and chronic leakage problems. I was originally told to leave the 9v battery alone as it would require retooling some plastic. However, after the initial performance tests performed, it was apparent that the original design was just fine, and it was the battery that was the real problem. I replaced it with 4ea AAA batteries, haggled with injection molding people, tweaked a linear voltage regulator a little, and lived happily thereafter. I even convinced the FCC that it didn't require re-certification. [1] For example, 8.8V to 5.5VDC: 
--
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
Reply to
Jeff Liebermann

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