On 11 Apr 2015 03:23:51 GMT, DoN. Nichols wrote:
On 2015-04-10, Frnak McKenney wrote:

[ ... ]

Has anyone here used -- or even seen -- a pair of "cigarette lighter"
plugs wired together and sold as a "jumper cable"? The concept certainly
has appeal -- battery-to-battery jumper cables are heavy, bulky, and
stiff -- but how would it handle the (say) 100A "cranking current" needed
to get an automobile with a dead battery started? Ian's "8-10A", which is
an order of magnitude lower, seems like a good working figure for that
kind of connection, and with that limitation even a superconducting cable
wouldn't be enough.

Or have I missed something?

I think that the intended application is to plug it into both
car's outlets and leave the supply car idling for some time. This can
get sufficient charge into the "dead" battery -- and likely current
limited by the fairly small gauge wire used. (I'll bet the wires get
noticeably warm in use. :-)

If the dead battery is sufficiently dead, this won't work, of
course.

Okay. Thanks, DoN. And Larry. And Lloyd. And anyone else i missed. grin

Using it to recharge the battery makes a lot more sense. I think I saw
the two plugs and the cable, noticed that it was advertised for starting
a car with a dead battery, and mentally filed it under "You've GOT to be
kidding!" As you all point out, limited to 10A it (probably) won't smoke,
and in 10-20 minutes would pump enough electrons into a discharged-but-
still-good battery to let someone attempt to start a car with it.

Hm. Let's see... add overcurrent protection, voltage measurement, a
Coulomb counter, and an LED/LCD display, and the gadget could tell you
when the recipient battery was ready to "take its shot". Not a
guarantee, of course, since I assume different vehicles require more or
less amperage to get started, but a hint at least of when _not_ to try.
And the package would still weigh a heck of a lot less than regular 12'
100A jumper cables (even the aluminum ones).

Interesting...

Toss in a pair of lighter-plug-to-pair-of-battery-clips adapters for
those cases where one or the other party (or both) lacks a "cigarette
lighter" socket and it's a really useful gadget. I think I owe some
company an apology for my nasty thoughts. grin

Thanks again for the enlightenment.


Frank
--
"No, the captain does not believe in indiscreet questions.
He believes the only way to get pertinent information is to
ask impertinent questions."
-- Findell to Lennier / Babylon 5:Meditations on the Abyss
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney aatt mindspring ddoott com