On 2014-10-26 18:40, jdebert wrote:
On Sun, 26 Oct 2014 15:18:17 +0100 (CET)
"Carlos E. R." <> wrote:
Language barrier here: What is "jumping a battery"?
Shortened form of "jump start", a method of starting a car with a flat
battery by using another fresh battery, attaching cables (the "jumper")
between the two batteries so they are in parallel.
Ah! Yes. I have done it myself. I usually carry in the trunk a pair of
cables for the purpose. So that's how you call it, jump start. :-)
There is a very large current surge from the other
car's battery to the
flat battery that generates gas, heats the flat battery and creates
some defects on the plates, etc. Sometimes old batteries pop their caps
or even crack when jumped.
Wow. I have not seen that!
I had to "jump start" my previous car about two years ago. I left it on
the long stay airport car park, for a month. When I came back, it would
not start. The parking lot had a battery they use for that very purpose,
specially made, and we started the car effortlessly. Later on that same
day, I stopped for a coffee - absolutely needed, after more than 12 hour
flight with changes - and it would not start. I had to jump start it
from a friend's car, with whom I was taking that coffee.
So I drove straight to a battery shop, left the car running at the shop
front, and bought a new battery then and there. If I went home to sleep
first, it would not have started and I could not have bought a battery...
I had decided already that it was damaged, if it could not hold enough
charge for a month in summer, to even power the lights.
On another occasion, on that same car, when the garage was doing
scheduled maintenance on the car, they "detected" that the battery
wasn't in good shape (I suspect they apply a heavy load). Sure enough,
it would not start on leaving the garage. So the garage person, not a
mechanic, but the office chap, applied a fast charger to the battery,
without unplugging it first. The car started and I left. About three
weeks later, my dashboard electronics (speedometer, etc, all indicator)
froze. Everything. Seconds later, it was working again. This happened
more and more over the following months, till it finally died
completely. Also, my remote car lock stopped responding. Radio was
perfect (because it was off during the charge).
I did not then relate these problems with the battery fast charge, but
it was surely the culprit. Years later I read that the procedure applies
a high voltage (22 volts?) which can fry any electronics not disconnected.
But I did not know this, and had to pay for replacements parts...
Live and learn.
When we learn enough, our cerebrum fills up and we die, because we are
not Cylons and can't replace ourselves. >:-P
He. While waiting for the replacement instrumentation, I drove around
with a multimeter connected to the alternator, tied to the dashboard.
That multimeter has a frequency meter. I made a table relating road
speed and alternator frequency, on several gears, to avoid crossing the
speed limit and getting a fine. ;-)
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 "Bottle" at Telcontar)