"J Burns" wrote in message
When I got home, I automatically opened the driver’s door and pulled the
hood latch release. Well, how about that! My car has one, too!
I don’t remember what I don’t think about. I’ve been opening that hood
30 years without thinking about it. If I wanted to open the hood, I’d
open the door and release the latch. The rest was automatic, without a
thought in my head. A couple of days ago, when I was already standing
at the hood, I couldn’t remember that there was something before it in
my mindless sequence.
JB When the hair turns gray the memory goes away. DAMHINT WW
New fangled safety stuff. I had the hood open on my '60 Plymouth. It
certainly is interesting driving while looking through a 4" aperture. iirc,
my wife had the same situation driving her father's Checker.
Yeah, I've thought about that. Think I'll see if I can get a bent
wire under the hood. Keep it in the trunk. Some you can at from the
ground. Have to look so I'll be prepared. Then it'll never happen.
Actually I'm more concerned with the gas cap door on my Grand Am.
The only car battery I ever got less than 5 years out of was a
lifetime guaanteed battery from Canadian Tire. It took 3 to get
through 5 years. Usually I get 7 or more years out of a battery -
have gotten as much as 12. And that is with no extra-ordinary
maintenance - heck I don't even LOOK at the battery between oil
changes. The only time I ever connect a charger to it is if I leave a
door open or lights on for too long while tinkering on something else
on the vehicle and the battery gets too low to start.
On 10/3/14, 2:00 PM, email@example.com wrote:
I never paid attention to state of charge until I traded my generator
BMW motorcycle for an alternator model. It was 180 Watts, but it turned
too slowly. In high gear, I think I had to be up to 45mph to start
lifting the load from the battery and 55mph for the full output.
The headlight law meant the battery had to supply 6 amps or so, below
highway speeds. It also meant the regulator put out 13.8 volts instead
of 14.4. Suppose the battery was down 5 amp hours and I got on the
highway, charging at 10 amps. One might think half an hour would do it.
It would take a much longer run because the battery would accept less
and less current, especially at 13.8 volts.
Chronic undercharging meant big, expensive batteries didn't last long.
That's how I got into routinely checking the state of charge and using a
A battery in a vehicle with the alternator that charged full-time,
wouldn't have the same problem, but I got into the habit of checking
states of charge, out of curiosity. Some were fully charged. Others
were at 50 or 75%. They still functioned well enough that one might not
have known they weren't fully charged, but leaving them that way would
shorten battery life.
A lot depends on how a car is used. My neighbor used his car for
errands. It may have run an hour a week. The battery was apparently
My neighbor bought the battery in 2000 and discarded it in 2002. By
occasionally putting it on a charger overnight, I got reliable service
until 2013. That's 6-1/2 times the rated life of the battery. I don't
think it would have lasted so long with the chargers I used to have.
VW 412 had hit a cow and was in the body shop for months. When it came
out the hood latch would not release. I was on my way from Livingstone
to Lusaka on the old Nakambala sugar estate road - a level, straight
gravel road - at about 80mph when all of a sudden there was a "snap" a
quick shadow across the windsheild, and a gaping hole where the
"bonnet" was a split second before. Looking in the nirror I saw it
settle to the road behind me -, not a mark on the roof or windscreen.
Snapped the hinges clean off and went straight up!!!. I tied it down
with rope and a strap to the next "town" where I had the hinges welded
back together and continued my trip to lusaka with it tied to the
front bumper, where I bought a used hood , hinges, and latch and
bolted them on.
To get a voltage rading on a battery that means anything , the battery must
be under a load. An almost dead or bad battery will still show about 12.6
volts without a load. Turn the headlights on to put a load on the battery
if nothing else. Do tht on a new battery and you will have a baseline to
compair readings on at a later time.
Even if the only load is a small ammount like you say, if that drags a
battery down while taking a voltage measurment, the battery is bad. Drawing
even 100 milliamps should not effect the open circuit voltage of a battery
enough to be measured with most meters.
This email is free from viruses and malware because avast! Antivirus protection is active.
That's a whole different subject.
We've been talking about full charge voltage.
What we have /not/ been talking about is the actual condition of the
If a battery can hold approx 10.7 volts under a moderate load that means
the battery is in good condition...but does /not/ let you know if you
started out with a 100% or a 90% charged battery.
There is no mechanical or electronic regulator on an alternator
equipped vehicle that measures or controls output current. On the old
generators, yes - you had a 3 unit regulator - one limitted the
voltage, one limited the current, and the other disconnected the
battery from the generator when the output voltage was lower than the
battery voltage to prevent the generator from "motoring" and wearing
the battery down.
An alternator regulator only LIMITS the output voltage of the
alternator. Current control is looked after by the resistance of the
stator windings and the circuit at the output voltage. When the
current is high, the regulator does absolutely nothing. The alternator
puts out whatever current it can, with the voltage being controlled by
the load. As the load drops and the voltage goes up, the regulator
reduces the voltage, and therefor the current, going into the rotating
field of the alternator - which reduces the output voltage of the
alternator, which reduces the current passed into the higher
resistance of the battery as the battery charge increases.
In MOST alternator systems, the diodes in the 3 phase bridge rectifier
are the only thing preventing the battery current from flowing back
into the alternator stator windings.
Most alternator sytem regulators are, in effect, constant voltage
regulators with a "soft" supply.
On 10/3/14, 4:02 PM, firstname.lastname@example.org wrote:
Ah, one long word looks about the same as another to me!
You've refreshed my memory and you're right. Maybe I'm getting mixed up
with a generator regulator I've seen. Alternator resistance might
account for what I've observed, slightly less voltage with more load.
I seem to remember that the regulator contact was like a SPDT switch.
Maybe I can find a diagram on the internet. I remember the motorcycle
had a rectifier board with 6 big diodes for the output current and 3
small diodes to feed the exciter current to the regulator. If there
wasn't enough output there, the exciter current came from the battery
through the alternator indicator bulb. Instead of switching off, it
faded as the engine sped up.
On my Dodge Ramcharger service truck I had a set of welding cable
receptacles on the front fender, controlled by a starter solenoid -
and a set of 30 foot welding cables with battery clamps on the end. I
could pull in the driveway behind a limo with a dead battery and give
it a boost.
And a 75% charged battery can still read 12.6 volts open circuit.
AT REST the difference in voltage of a given typical automotive 12
volt battery is less tha .1 volt between 70% and 100% charge at a
given temperature. A warmer battery will produce a higher open
circuit voltage than a colder battery.
Also, the initial SG of a lead acid battery varies by geographic
region - with SG of 1.245 beig quite common in equatorial regions to
eliminate or reduce corrosion and self discharge. Stationary batteries
can be even lower, while deep cycle batteries for arctic use may well
excede 1.300. An expanded scale voltmeter can be effective at
measuring state of charge for a particular battery set under
particular conditions - by comparing the voltage to a pre-determined
discharge voltage profile.
I've had totally dead AGM batteries from a UPS read 13.6 volts open
circuit, and they wouldn't make a #194 bulb glow (and read less than 3
volts with that small load).
On 10/03/2014 03:26 PM, email@example.com wrote:
I should probably mention the ".84" rule which those in the industry use
There is a .84 difference between a LA cell's open circuit voltage and
specific gravity. (at 77F)
Viz 2.12 volts minus .84 equals a specific gravity of 1.280
On 10/3/14, 4:26 PM, firstname.lastname@example.org wrote:
I've heard of manufacturing batteries with different acid concentrations
for different climates, but I don't know much about it.
This page has a link to download a spreadsheet of
temperature-compensated SOC tables.
It shows that SG changes with temperature. The same battery can have a
SG of 1.25 at 120 F and 1.30 at 0 F.
I had a truck battery that apparently had an internal fracture.
Occasionally, it would produce no current, but the open-circuit voltage
was good. Then it would start working again.
Pulsetech says they have a patented pulse charger that will restore dead
AGM and flooded-plate batteries by getting rid of sulfate crystals.
They have a contract with the Army. In one command, the battery turnover
rate dropped 90% after Pulsetech converted it to AGM and gave the Army
techs a short training course.
> couldn’t remember that there was something before it in my
> mindless sequence.
There are two latches on a hood release. The inside latch unlocks the
hood, so it's not locked down, but you also have to depress the spring
loaded hood release latch before raising the hood. Otherwise, if you
were to pull the hood release inside the car while driving down the road
at 60 mph, the hood would fly open and block your view of the road and
possibly cause a very serious accident. That second spring loaded latch
ensure the hood doesn't open unless and until an actual human being
depresses the spring latch and lifts the hood.
I think that "something before" you couldn't remember was the spring
loaded latch that needed to be depressed before the hood would open.
I would close the hood normally, and see if you can open it normally.
Do that several times. If all seems to be in order again, put that
experience about not being able to open the hood in the same bag as crop
circles and lights in the sky.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.