I've seen that, where the car starts or at least almost starts just as
one lets go of the key. You've explained it.
The tendency was to think, I stopped cranking just a moment too soon and
if I'd cranked another second, it would have started, so of course
people keep trying. But your explanation accounts for why that's not
It is, in slightly more detai, that the voltage goes up the moment the
key is released, because the starter is not connected anymore, but the
flywheel etc. are still turning and the higher voltage is enough to make
That used to be a common problem in the days of point fired (and
early electronic ) ignition systems using ballast resistors, where the
"crank bypass" failed. Inadequate spark voltage when cranking because
you basically had a 7 volt coil running through a resistor, with a
resistor bypass when cranking to give it cranking voltage (generally
closer to 9 volts) when starting. If the bypass failed you had only 9
volts feeding the coil/resistor and closer to 5 across the coil itself
- not enough to fire. Releasing the starter allowed the full 12 volts
to the coil/resistor - and 7 or 8 to the coil - lots of spark to fire
the engine over.
Also not out of the ordinary when an ignition switch would start to
fail - no connection to IGN when in STart position. - or if someone
wired the ignition to the ACCessory position (which was shut off
during crank to take heater and wiper and defrost loads off when
On Sat, 05 Jul 2014 18:30:48 -0400, Stormin Mormon
On my '53 Coronet I had lucite rods mounted on the edge of the
headlight with a little red "gumdrop" on the top that lit up when the
lights were on. For as common as they were "back in the day" it's
strange I can't find a picture of them on the internet!!
On 7/5/2014 10:47 PM, firstname.lastname@example.org wrote:
I remember them
about halfway down the page
I have a 6 amp trickle charger and a digital timer that I want to use
for charging a spare battery for my car. Batteries can go dead just
about any time 5 years after purchase, and so I'd like to keep a spare
battery on hand.
I connect the leads of the trickle charger to the battery posts, plug
the trickle charger into the digital timer and plug the digital timer
into the wall.
My digital timer will allow me to charge the battery for any where from
1 minute to 23 hours and 59 minutes every day.
What's a reasonable amount of daily charging time to use?
My own thought is that if people commute to work every day in their
cars, and the trip is anywhere from a 10 to 20 minute drive, then their
alternator spends approximately 1/2 hour every day charging the battery.
However, this seems excessive to me. I'm more thinking of 5 to 10
minutes of charging every day just to keep it fully charged.
Does anyone have any rules of thumb to go by or experience in this
Self-discharge is much faster in summer heat than in winter cold. I use
a digital volt meter when the battery has been sitting several hours.
For a fully charged conventional or low-maintenance battery, the fully
charged voltage is about 12.6, depending on temperature (12.6 at 90F to
12.8 at 40F). A maintenance-free battery varies less (12.8 at 90F to
12.75 at 40F).
Both types lose about 0.2 V at 75% charged, 0.4V at 50%, and 0.6V at 25%.
So if you take a voltage reading 12 hours after charging a battery fully
and subsequent readings are taken at roughly the same temperature,
they'll tell you the state of charge. I like to charge before it's down
I have a manual 6 A charger but don't use it anymore. A good
microprocessor charger not only regulates the voltage but takes
temperature into account in setting the correct voltage. Mine doesn't
say so, but I've discovered that it charges with pulses. That's kinder
to the plates than a steady voltage.
A lot of modern chargers charge a battery fully, switch off, monitor the
voltage, and turn back on when it drops a certain amount. That way, you
can connect it and forget it.
Well, if the car is driving to and from work it is being started at
least twice and you need to put that power back in. With a battery
just sitting, that is not required 5 minutes a day should be more than
adequate. I'd be more likey to do 10 or 15 minutes every saturday, or
I've been surprised by batteries before.
I had a battery that didn't have enough juice in it to turn over the
starter motor. The starter would just make a ticking sound when I
turned the key.
So, I checked the battery voltage with a multimeter. 11.2 volts.
I figured "Well, that's pretty close to 12 volts, it should start."
Then I phoned up a battery place, and they said the battery was garbage.
It should have about 12.6 volts, and 11.2 volts is a dead battery!
11.2 volts is almost 90 percent of 12.6 volts. Does anyone know if the
cold cranking amps of a battery with 11.2 volts would be almost 90
percent of it's rated cold cranking amps?
I'm thinking that maybe when the voltage gets down to 11.2 volts, the
ability of the battery to deliver amperage is much more severely
reduced, and that's why the starter motor wouldn't turn the engine over.
I can see how it's possible to have 11.2 volts in the battery and
almost no amperage. If you simply connect two 9 volt TV remote control
batteries in series you'll have 18 volts, but almost no amperage. I
guess it's really the amperage that determines if the starter MOTOR
cranks because motors work on magnetic fields, and it's the amperage
through the wire that determines the strength of the magnetic field
around that wire, not the voltage across the wire.
As you found out, "nope".
The ~11 V indication is you've got one bad cell. In Pb-acid battery,
the voltage/cell is just a little over 2V/cell when in good
It'll either be that or it's not charged or it's bad; those are the
perhaps the vehicle isnt charging good?
put your volt meter firmly on the battery terminals with the vehicle running, it must be at least 13.8 volts
the only way to really test a battery is to charge it overnight, then load test it to see if it puts out enough current like 200 amps and stays around 11.8 volts for x time.
OP needs his alternator tested, a new battery, and since he repeatedly leaves his lights on, a alarm....
its easily added by any shop that does auto electronics for under 20 bucks
perhaps the battery is still under warranty? of some type?
sfor awhile sears and others sold a battery with a switch on it that could be moved to access reserve power, for people who leave their lights on.
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