From: John De Armond
Subject: Re: Who sells jumper cables that connect to cigarette lighters?
Date: Thu, 10 Feb 2000 22:22:32 EST
Newsgroups: rec.autos.tech

Jacques Labonte wrote:
> 
> Unless the laws of physics don't apply to everybody, charging a batterie for
> 15 mins at 10 amps hours will transfer 2.5 amps. If it is enough to start a
> car it must be EXTREMELY small. 

Well Jock, the laws of physics apply apply regardless of whether you
understand them or not.  The current flow is in amps and not
amp-hours as you mistakenly said.  The total energy delivered is
amp-hours and not amps as you mistakenly said.  I know, this is
complicated but keep trying.  You'll probably get it.

For a battery that is just below the threshold of cranking, an
additional 2.5 amp-hours is more than enough to kick things off. 
2.5 amp-hours discharged in, say, 1 second is 150 amps over that
interval - more than enough to spin up the starter on most vehicles.
If not, wait 30 minutes next time.

>And you cannot boost 12 volts D.C. unless you
> have an electronic inverter that cost 10 times a good booster cables set and
> the net result after reconverting to 12 volts D.C into the other car would
> still be 2,5 amps less the loss in the booster. Sorry it doe's not work

Electronics isn't one of your strong points, is it?  let's see if we
can work on it.  If you take a look at
http://pdfserv.maxim-ic.com/arpdf/AppNotes/A0217.pdf, you will see
an application note from Maxim describing a nifty little inductive
boost converter that uses a chip, a couple of transistors and a
dozen minor components - surely under $10 worth.  This DC-DC
converter will produce whatever voltage you desire at a current
limited only by the capacity of the FETs.  This little puppy will do
the conversion at a 97%+ conversion efficiency.

On a more practical level, if you go to http://neonjohn.4mg.com,
/files/car/dc_dc_converter.jpg, you can see a photo of one of my
cigarette lighter-to-cigarette lighter charger, in this case, one
designed to charge portable battery packs.  It provides 1 amp at 14
volts.  I paid $10 for it and use it to charge the battery pack I
use with my radar gun.

And finally, here is where you can buy one, complete with a
picture.  A tiny little romp on any search engine would have saved
you from looking really dumb.  Try it next time before posting.

John

> 
> Neon John wrote:
> 

> > > I don't think you quite understand what you are looking for.  As some
> > > people here pointed out, you cannot start a car by connecting it to the
> > > other car's cigarette lighter.  There is absolutely no way to do that.
> >
> > Interesting.  Wonder why it always works for me.  With the jumper
> > car's engine running, connecting the cig lighters together for about
> > 15 minutes will transfer enough charge to the jumpee's battery to
> > get it to crank. The really good cig to cig jumpers contain an
> > electronic voltage booster so that the charging will take place even
> > with the jumper's engine off.
> >
> > The bit about this procedure being mandatory for new cars is, of
> > course, bunk.  Conventional jumpers work just fine.  But it's awful
> > nice to be able to pull a coil of wire out of the glove box and give
> > a quick boost to someone whose car won't quite crank than it is to
> > drag out a heavy set of jumper cables.

From: John De Armond
Subject: Wally-World  heads-up - Emergency Jump starter
Date: Fri, 31 Mar 2000 05:40:05 EST
Newsgroups: rec.outdoors.rv-travel

There's a nifty new product on the market called the "Start Me Up!"
(gag) emergency jump starter.  this is a little package about the
size of a couple of packs of cigarette packs that will charge a weak
battery enough to crank the engine.  Inside the package is a high
voltage (36 volt) "polapulse" style flat cell battery and a male
cigarette lighter plug.  When the battery is activated, it will
produce enough power to bring a car battery that is just barely
discharged (clicks the solenoid, etc) up enough to crank a healthy
engine.  Claims to do it in 5 minutes.  It has an LED that burns red
while charging and flashes green when charging is complete.  It
claims a shelf-life of several years.  It easily fits in the glove
box.  It is disposable and is discarded after use (after salvaging
the very nice cigarette lighter plug, of course :-)

I tested one on my Cadillac with the 425 cu inch engine by leaving
the lights on until the solenoid clicked and then applying the
device.  It cranked the engine - barely.  This is pretty much a
worst case example because the Caddy has a weak starter anyway.  My
wife actually had to use one of these on her Camry and it worked
fine.  The label says it will not work on diesel engines.

The biggest problem with these devices is they were expensive -
$19.95 from Wal-mart.  Apparently they didn't sell because tonight I
noticed them on the clearance rack for $10 ea.  At this price, they
are a real bargain.  I bought a bunch.  A couple can easily be
stashed in the RV for just in case you really do run both the house
and cranking batteries down.  Grab 'em while they're available.

One should not get one of these devices intending on using it to
power some sort of 12 volt device.  One, the voltage is high to
rapidly charge and warm the vehicle battery.  Two, the life is very
short, whether the power is used or not, once activated.

The patent that applies to this device is 5,883,491 and can be
viewed here: http://www.uspto.gov/patft/index.html.  It's an
interesting patent to read.  One, it illustrates just how BAD patent
verbiage can be.  Two, it illustrates the critics' charges that the
USPTO will now issue a patent to almost anything, relying on the
courts to validate the patent.  Three, he makes some interesting
claims about how the device works.

John

From: John De Armond
Subject: Re: Wally-World  heads-up - Emergency Jump starter
Date: Fri, 31 Mar 2000 13:08:32 EST
Newsgroups: rec.outdoors.rv-travel

Joe Kasunich wrote:
> 
> I've seen these disposable devices on the shelf and thought about trying
> one.  Thanks for doing the test and sharing with the group the results.  One
> concern I have is the "disposable" principle of it.  Anyone know the type of
> internal battery contained within these units.  I wouldn't consider myself a
> diehard conservationist, but I would question the disposal of these
> batteries.....most battery packages now recommend recycling waste batteries

The Polapulse battery is a special version of the LeClanche (aka
carbon-zinc) battery.  In other words, the same chemistry as
ordinary flashlight battery (not alkaline).  Contents include zinc,
potassium hydroxide, carbon dust and manganese dioxide and usually a
little powdered copper.  Nothing bad.  I can't imagine anyone
objecting to this stuff being thrown away. (Actually I can, among
the irrational enviro-radicals but...)  What Poloroid did when they
developed the Polapulse battery was invent a physical arrangement
with a small footprint and the ability to supply a large surge
current over a short period of time - just what was needed to
operate the film transport in the Poloroid instant cameras - and
boost off weak car batteries!

The only concern I have with this produce is that if the car battery
is weak and approaching the end of its life, i.e., having a
relatively high internal impedance, the 36+ volts this thing puts
out could injure vehicle electronics.  With a healthy battery, this
is of no concern.  However, if you know your battery is on its last
leg, it's a good idea not to use this thing if you also have a
computerized engine.

John

From: John De Armond
Subject: Re: Wally-World  heads-up - Emergency Jump starter
Date: Fri, 31 Mar 2000 13:14:15 EST
Newsgroups: rec.outdoors.rv-travel

Miffed One wrote:
> 
> <<I've seen these disposable devices on the shelf and thought about trying one.
>  Thanks for doing the test and sharing with the group the results.  One concern
> I have is the "disposable" principle of it.  Anyone know the type of internal
> battery contained within these units.  I wouldn't consider myself a diehard
> conservationist, but I would question the disposal of these batteries.....most
> battery packages now recommend recycling waste batteries >>
> 
> I saw a piece on TV from Consumer Reports in which they opened up the "battery
> pack." It was a bunch of D-cells strapped together! And the D-cells
> specifically said "Do Not ReCharge". Don't know if it was the same one you're
> looking at, but they said it was bought at a large discount store, and the
> price was around $20....

NO!  It is not that type of device.  To get 36 volts, one would need
24 cells.  That would be a huge device.  D-sized batteries cannot
supply the surge current of the Polapulse batteries because their
physical construction is not correct for that type of service.  This
applies to both ordinary and alkaline batteries.  The type device CR
tested might do the same function but it would be slow and it could
not perform the other functions claimed by this device in the patent
(cell warming, cell surface scouring, etc).  

John

From: John De Armond
Newsgroups: rec.autos.tech
Subject: Re: Are Cigarette lighter Jumper cables bad or good?
Date: Sun, 25 Jun 2000 04:28:32 -0400

AZGuy wrote:

> On 25 Jun 2000 03:35:15 GMT, sails97@cs.com (Sails97) wrote:
>
> >I have been hearing a lot about jumper cables that just pop into your
> >cigarette lighter, does this REALLY work?  Is it going to bugger up the
> >electrical on my car.  Will my wife no longer have to call to figure
> >out how to jump a car?
> >
> >This really seems to good to be true.   Please email me with feed back.  -
> >sail97@juno.com
> >
> >Thanks
> >
> >Craig
>
> Lets do the math.

Yes, do the correct math, though.

> A starter will draw anywhere from about 100 amps to
> 300 amps depending on lots of factors.  If your battery is not strong
> enough to start the car then it means it can't put out the 100+ amps
> needed.  So if you jumper to another battery you will have to provide
> the missing amperage.

Nope, sorry.  Unless your jumper cables are made from welding cable
(as mine are), one cannot supply cranking amperage through jumpers.
The typically 8 gauge wire that "k-mart specials" simply have too
much resistance to allow that kind of current to flow.  What they DO
do is allow the donor car to fairly rapidly charge the receiver
car's battery.  Since a "dead battery" that will still chug the
starter or click the solenoid is almost capable of turning the
engine over and since it takes a lot less current to turn the motor
than to start it turning, the few minutes of charging that typically
takes place is usually enough.  And who hasn't had to stop and wait
for the battery to "rest" after the first attempt to jump-start
failed?  In reality, giving the recipient battery time to charge
some more.

> The cigarette lighter is fused with a 15 amp
> fuse typically.  So the most amperage you can supply without blowing
> the fuse is going to be 15 amps.

Correct.  And the better cig lighter jumpers have DC-DC inverters
inside the black box to regulate the current flows even if the donor
car's engine is off.

> I suppose there may be some cases
> where that's all the extra omph you need to make it start but I'd hate
> to count on it being enough.  Instead of thinking of the cigarette
> lighter "jumper cables" as jumper cables, think of them as a way to
> easily connect to do a recharge of the battery.  Even then the donor
> vehicle could put more then 15 amps into it, but assuming it doesn't,
> you could let it recharge for 15 minutes and then try starting it.
> I've had jumper cables get so hot during a jump that the insulation
> melted on them - I'm pretty sure you would not want that kind of
> current going thru your cigarette lighter.

Doing a little math with Ohm's law will show you that heavy current
will not from lighter to lighter through 12 gauge or lighter jumper
wire with only a couple of volts to drive it.

The fact is, these cig lighter jumper sets work most of the time -
all the time if you have patience to give it enough time to work.
They're practically idiot-proof and fit in a glove box.  Certainly
better than conventional jumpers in the hands of a novice.  I
imagine that it's a whole lot easier to get a stranger to allow you
to plug  into his cig lighter than it would be to pop the hood and
muck around with his battery.

I keep a set in my wife's car.  She doesn't want to know how to use
conventional jumpers.  She's successfully used the set more than
once.  To her, math doesn't mean squat.  That they work does.

BTW, good jumpers don't get hot.  My 25 ft long jumpers made from 00
gauge welding cable and NAPA 300 amp clamps don't get the least bit
warm while cranking another engine - even if the battery is missing
from the recipient car.

John