car battery failure -- question
tanya
X-posted
need to get a general idea on how frequently brand new auto batteries
fail (while the car is NOT running and NOTHING was left on)
it was not started for several days
(the battery was 4 months old)
(voltage was 0 and after it was reCharged it was 4 :-)
thank you
--
toAnswerSend2:userName:tjtmd
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separate these with the at sign
Sofie
unless there is a fault in the car's electrical system that is causing
excessive "OFF" drain, once the battery is fully charged, it should be able
to start your car after sitting there for many months..... in the case of
my motorhome, 6 months!
If the battery is draining just after a few days, there is either a problem
with the car's electrical system and charging system.... or the battery is
bad.
A fairly easy check for most shops ..... and some auto parts stores will
even provide a free preliminary check of these things for you.
--
Best Regards,
Dan Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
"tanya" <seeAd...@bot.tom> wrote in message
news:3EF8788B...@bot.tom...
Asimov
--- on the topic of "car battery failure -- question"
ta> From: tanya <seeAd...@bot.tom>
ta> hello
ta> X-posted
ta> need to get a general idea on how frequently brand new auto batteries
ta> fail (while the car is NOT running and NOTHING was left on)
ta> it was not started for several days
ta> (the battery was 4 months old)
ta> (voltage was 0 and after it was reCharged it was 4 :-)
ta> thank you
You might try a solar panel as a trickle charger? Then you would never
have to worry about it. Generally it should be okay for many months but
the car computer might be draining some current. Leaky alternator diodes
will also drain a battery quickly in perhaps say a couple of days or so.
In really cold weather a car battery loses capacity even more quickly.
For instance I would run my vacationing friend's car once a week for 10
minutes in -5'F weather. Car batteries are almost a black art!
... Real techs don't lick nine-volt batteries!
Charles Schuler
"Sofie" <so...@olypen.com> wrote in message
news:vfh00rq...@corp.supernews.com...
> tanya:
> unless there is a fault in the car's electrical system that is causing
> excessive "OFF" drain, once the battery is fully charged, it should be
able
> to start your car after sitting there for many months..... in the case of
> my motorhome, 6 months!
> If the battery is draining just after a few days, there is either a
problem
> with the car's electrical system and charging system.... or the battery is
> bad.
> A fairly easy check for most shops ..... and some auto parts stores will
> even provide a free preliminary check of these things for you.
What with all the computers that keep running in modern vehicles (such as
anti-theft), 2 weeks of inactivity can be a killer!
Bruce Chang
"Charles Schuler" <charles...@comcast.net> wrote in message
news:SCydnWCKYNb...@comcast.com...
computers? While the car is off? I hardly call anti-theft a computer.
What does it compute? How long it's been inactive? How many people have
disregarded the alarm? 2 weeks of inactivity for any brand (regardless of
it being new or not) battery should be a piece of cake.
Now it's possible that the battery you got was not a good battery, albeit
new. Been there, done that. Go back and get it replaced. If the battery
was given enough time to sulfate, it will not charge. Typically I would
think if the battery has been drained for about 24 hours, it more than
likely is toast.
-Bruce
Jim
left for more than a couple weeks. Just ask the guy at your local used
car dealer.
Mike Romain
I went through 3 of one brand in a year. They did the same, dropped to
0.
I changed brands...
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Daniel J. Stern
> What with all the computers that keep running in modern vehicles (such
> as anti-theft), 2 weeks of inactivity can be a killer!
That's wrong. If your car's battery goes flat in two weeks or even two
months, it is because there is excessive IOD or the battery is faulty, not
because of "all the computers".
I'm amazed that *three decades* after computers first appeared in cars, we
still have people who blame everything from hard starting to dashboard
rattles on "the computer".
DS
tanya
thank for the reply...
just wonder since it read Z.E.R.O. on the voltmeter (correct setting:) when it
was found dead (ie was not running etc) and then, we recharged it but it only
went to 4 volts wouldn't those 2 *tests* point to a bad battery? since the
alternator wasn't involved when it read zero... the electrical could be at
fault also but the battery recharger was independent of the car -- isn't it?
i wish i know autoMechanics by tomorrow:)
thanks again!
sincerely
Tanya
--
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tanya
well this is not a modern vehicle............
thanks
tanya
ok so since i hadn't called aaa IMMEDIATELY, I KILLED IT by waiting?
it read zero when it died (a very quick death within a couple of days of running
ok)
Daniel J. Stern
> The parasitic load on today's cars is indeed high. Most will be dead if
> left for more than a couple weeks.
Sorry, no, repeating this nonsense does not make it true.
DS
BillW
regularly leave my car for two and three weeks at a lot while traveling and
have never came back to a dead battery. Since the battery went dead in a
couple days either the battery was defective, something was left on
(lights), or there is a short. Speculating can't solve the problem, only
proper diagnosing it will....
"Jim" <jv9...@yahoo.com> wrote in message news:3EF8C85D...@yahoo.com...
Lon Stowell
I wonder what the load actually is? Any anti-theft or similar
stuff would be expected to be extremely low current, but dunno
if it is in the range similar to a modern watch innards where
a measly battery runs 3-4 years [at least on mine]. Have left
vehicles sitting for a coupla months with no noticeable
difference in startup.
Now, if all those sirens, horns, etc. on the typical misadjusted
alarm system were to drain the battery in a matter of days, this
would not be an entirely bad or unjustified thing...
Mark
says...
>
> > > need to get a general idea on how frequently brand new auto batteries
> > > fail (while the car is NOT running and NOTHING was left on)
> > > it was not started for several days
> > > (the battery was 4 months old)
> > > (voltage was 0 and after it was reCharged it was 4 :-)
> > > thank you
> > >
>
>
> was found dead (ie was not running etc) and then, we recharged it but it only
> went to 4 volts wouldn't those 2 *tests* point to a bad battery? since the
> alternator wasn't involved when it read zero... the electrical could be at
> fault also but the battery recharger was independent of the car -- isn't it?
> i wish i know autoMechanics by tomorrow:)
> thanks again!
> sincerely
> Tanya
>
substantial, constant drain on it, and not something as
minor as the on-board diagnostics. It would require a
fairly substantial external drain, something pulling 5 Amps
or better, OR a catastrophic internal short, to cause this.
As to the battery returning to only 4 volts after charging,
this indicates the battery is shot and you've only got 2
good cells. The battery Could have been damaged, however,
as a result of the (possible) external drain. So...if
you're angling to get a new, free battery to replace the
"defective" one, you may or may not have a case. Without
checking the rest of the electrical system, there's really
no way to know.
--
Mark
The truth as I perceive it to be.
Your perception may be different.
Robert Hancock
not exceed the battery reserve capacity, in minutes, divided by 4. For
example, with a 100-minute RC battery, drain should not exceed 25 mA.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hanc...@nospamshaw.ca
Home Page: http://www.roberthancock.com/
"Lon Stowell" <lon.s...@attbi.com> wrote in message
news:3EF8DC00...@attbi.com...
Bruce Chang
"tanya" <seeAd...@bot.tom> wrote in message
If it were the case that you left your lights on and drained the battery and
then left the battery alone without charging it, yes. If the battery was
bad in the first place then you didn't do anything to speed its death.
There have been batteries (not deep cycle) that will survive a long time of
being discharged but I've found the longer the battery is discharged, the
less of a chance that you can recharge it and have it retain charge.
Immediately, no.. How long did you wait?
-Bruce
Ricardo Matos Abreu
"tanya" <seeAd...@bot.tom> wrote in message
Do a simple test: when recharging the battery with an external charger, do
it with the car leads disconnected, i.e., let the charger and battery
romance together ALONE.
After recharging, can you get read 14V or so at the battery terminals?
If not, yeah, the battery is gone.
Anyway, you have to buy a new battery. Recharge your new battery in the same
way, i.e., ALONE. Then connect it, but with an DC ammeter inserted at th
'plus' (+) lead, on the 10Amp or 20 Amp position (don't even THINK in
running the starter with the ammeter in place! You'd get roast ammeter for
dinner!).
Now you have a way to measure how much current your car is draining when
idle. Remember to turn of lights, shut doors, remove key, etc. Must be some
miliamps at most. If not, get the car serviced.
Once had a friend with a similar problem. Believe it or not, it was a faulty
dashboard clock draining the battery flat...
Ricardo
Charles Schuler
> computers? While the car is off? I hardly call anti-theft a computer.
> What does it compute? How long it's been inactive? How many people have
> disregarded the alarm? 2 weeks of inactivity for any brand (regardless of
> it being new or not) battery should be a piece of cake.
>
> Now it's possible that the battery you got was not a good battery, albeit
> new. Been there, done that. Go back and get it replaced. If the battery
> was given enough time to sulfate, it will not charge. Typically I would
> think if the battery has been drained for about 24 hours, it more than
> likely is toast.
Many call microprocessors and microcontrollers "computers." Lot's of cars
go dead in airport long-term parking lots. A static drain of 50 mA can
quickly add up to a big part of the capacity of a small car battery. For
example, in two weeks it's 50 mA x 336 h = 16.8 Ah.
Tomcat14
I just worked on a Mitsubishi Eclipse where the battery was going dead
constantly and was supposedly new.
The immediate current drain was 850MA for a few seconds before the
computer went into sleep mode and the losses dropped to 35MA. I look
for reasons when the drain is over 50MA.
Batteries can drop dead at any time. They can be intermittent also.
Plus you can have a malfunctioning relay that keeps something on
sometimes, but not at other times.
The only way to diagnose is to check with a meter.
William Walsh
If you really think it's nonsense, I suggest you read the manual that
came with your car.
Fact is, at least minimal portions of the engine computer and possibly
other computers DO keep running. All the time. Ever notice you've got
to pull the ECM fuse or disconnect the battery to get stored error
codes out or to force the thing to relearn how it runs the engine?
William
Sofie
All of this is very true..... but for your battery to go completely dead
(Zero Volts) in an few days, or even a week or two.... there has to be
something wrong with either the car or the battery. You are not going to
get to the bottom of this without a knowledgeable mechanic or battery
replacement shop checking the electrical system and the battery.
Here on the newsgroup, all we can do is GUESS and CONJECTURE ......
.... so you can make an intelligent repair decision with facts instead of
guesses you should take it to a shop, a auto parts store, etc...... someone
with a meter and with know-how.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
--------------------------------------
"William Walsh" <wm_w...@hotmail.com> wrote in message
news:ef0f88e5.03062...@posting.google.com...
Larry Smith
news:Pine.SOL.4.44.030624...@alumni.engin.umich.edu
If you were to make some very rough calculations, using a hypothetical
500 ampere hour battery, with a drain of 0.150 amperes, the darn thing
should go flat in about 4 months.
150 milliamperes is a significant off current.
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
Charles Schuler
>
> If you were to make some very rough calculations, using a hypothetical
> 500 ampere hour battery, with a drain of 0.150 amperes, the darn thing
> should go flat in about 4 months.
>
Lon Stowell
Totally missing from this is any mention of what the actual
power drain is for all of this. Trivial to design electronic
systems for sleep mode with minimal ongoing power drain, then
add a high impedance power loss reset circuit.
Lon Stowell
Which is just under 20% of the Amp/hour rating of a tyical auto
battery. I rarely see dead batteries in longterm lots, and
when I do, it is usually a car where the battery cables look like
toxic waste, the battery is 15 years old, or there is some
unusual power drain. On the other hand, on cars with more
electronic doodads than a mall full of Sharper Image stores,
know folks who leave them alone for well over a month frequently
with never a problem. But then these folks tend to replace
batteries every 3-4 years and buy surplus capacity.
If there is a larger power drain due to a light left on and this
happens frequently, a typical non-deep cycle car battery will
usually sulfate so bad it can't be recovered. Particularly
if it was marginal in the first place.
Charles Schuler
> Charles Schuler wrote:
> >>computers? While the car is off? I hardly call anti-theft a computer.
> >>What does it compute? How long it's been inactive? How many people
have
> >>disregarded the alarm? 2 weeks of inactivity for any brand (regardless
of
> >>it being new or not) battery should be a piece of cake.
> >>
> >>Now it's possible that the battery you got was not a good battery,
albeit
> >>new. Been there, done that. Go back and get it replaced. If the
battery
> >>was given enough time to sulfate, it will not charge. Typically I would
> >>think if the battery has been drained for about 24 hours, it more than
> >>likely is toast.
> >
> >
> > Many call microprocessors and microcontrollers "computers." Lot's of
cars
> > go dead in airport long-term parking lots. A static drain of 50 mA can
> > quickly add up to a big part of the capacity of a small car battery.
For
> > example, in two weeks it's 50 mA x 336 h = 16.8 Ah.
>
> Which is just under 20% of the Amp/hour rating of a tyical auto
> battery.
Some are only rated at 40 Ah.
> I rarely see dead batteries in longterm lots, and
Happens often in the winter in states like New York.
> when I do, it is usually a car where the battery cables look like
> toxic waste, the battery is 15 years old, or there is some
> unusual power drain. On the other hand, on cars with more
> electronic doodads than a mall full of Sharper Image stores,
> know folks who leave them alone for well over a month frequently
> with never a problem. But then these folks tend to replace
> batteries every 3-4 years and buy surplus capacity.
>
> If there is a larger power drain due to a light left on and this
> happens frequently, a typical non-deep cycle car battery will
> usually sulfate
There is some degree of sulfation in any 3 year old battery.
Mike Berger
car manufacturers for glove compartment lamps, under hood lamps, etc.
do short, and the light can drain the battery pretty far down in a few
days.
A glove compartment lamp that always stays on won't be obvious.
Larry Smith
Note the term hypothetical.
Whatever unit I might have used would have been challenged.
Lon Stowell
>>>Many call microprocessors and microcontrollers "computers." Lot's of
> cars
>>>go dead in airport long-term parking lots. A static drain of 50 mA can
>>>quickly add up to a big part of the capacity of a small car battery.
>>
> For
>
>>>example, in two weeks it's 50 mA x 336 h = 16.8 Ah.
>>
>> Which is just under 20% of the Amp/hour rating of a tyical auto
>> battery.
>
>
> Some are only rated at 40 Ah.
I can only wonder if the owner is partially at fault here, but
decided to investigate with a real example.
Looked up a gewgaw laden vehicle in the factory service
manual. Ignition off battery drain is 5 to 20 milliamps,
with 20 milliamps being the threshhold where the service
tech is instructed to FIX the drain issue before
swapping the battery. The vehicle switches to the nominal
5 milliamps after 3 minutes of ignition off. This particular
vehicle has memories for everything, but admittedly it does
spec a fairly beefy battery with a big alternator. Not sure
where your 50 ma came from, it would be a "fix this" item
according to this FSM. [And a 40 ah battery in a vehicle
with that big key off drain would be manufacturer negligence
or owner negligence].
For the original question, this particular FSM is from the
same manufacturer, and it notes that after disconnecting
the battery from all load, wait 5-10 minutes. Then measure
the battery open circuit voltage.
Even a nominally "dead" battery should read near 11.7 volts.
Less most often means a dead cell.
A normal 75% charge, which the manual is clear about "don't
waste your time on load or alternator testing if not correct"
is 12.4 volts open circuit.
Jeff
"Tomcat14" <drilli...@yahoo.com> wrote in message
news:f1e74c2c.03062...@posting.google.com...
> constantly and was supposedly new.
> The immediate current drain was 850MA for a few seconds before the
> computer went into sleep mode and the losses dropped to 35MA. I look
> for reasons when the drain is over 50MA.
> Batteries can drop dead at any time. They can be intermittent also.
> Plus you can have a malfunctioning relay that keeps something on
> sometimes, but not at other times.
> The only way to diagnose is to check with a meter.
I see a lot of these Mitsubishi engine and computer
moduals, the internal problems could cause excessive
current draw.
Jeff
acidburn
thing was it would still charge but at 16v AC
Steve
Its easy enough to compute how long the car can sit idle IF you know
what the parasitic current draw is.
A typical battery has about a 50 tp 55 amp-hour storage capacity. That
means that if you know the current draw in amps, dividing it into 50
tells how long the battery will last.
Example: if you have a car that draws 20 milliamps (0.020 amps) of
current with everything shut off, the battery will be dead in (50/.020)
hours or 2500 hours. Dividing by 24 (hours per day) means that the
battery will be drained in 104 days, or 3 and a half months.
Now in all likelihood the battery will be too dead to start the car a
few weeks before then, so call it 2-1/2 to 3 months.
If the parasitic draw is 40 milliamps, then you've only got about 6
weeks storage capability.
I can't imagine a car with a normal parasitic load of more than about 50
milliamps, so I think that pretty well establishes that the "couple of
weeks" estimate is a bit excessive.
Old cars that have no parasitic draw can easily sit 9 months to a year,
even longer with a low self-discharge rate battery like an Optima.
Charles Schuler
"Steve" <n...@spam.thanks> wrote in message
news:MxudnUyZTZD...@texas.net...
Your calculations are correct. However, they assume full capacity.
Capacity is greatly reduced at low temperatures. This is a double whammy
since the engine is also tougher to crank. Second, batteries that are a
couple of years old suffer from sulfation of the plates which means reduced
capacity at all temperatures. Third, all batteries have a self-discharge
characteristic. Fourth, some cars have closer to 50 mA of static drain.
Folks who work in used car lots will tell you that this is a real problem
(if they are honest about it). So, perhaps we can conclude several months
best case and several weeks worst case. Many prefer to use worst case since
a car that won't start is no fun at all and can be a very bad situation.
Lon Stowell
No argument with your points... however, do you have an example
of a car that actually draws 50 milliamp when there is NOTHING
broken? And as important, what is the recommended battery for
that vehicle? Did some engineer really screw the pooch there?
I can come up with several instances of 5 milliamp, with notes
that 20 is not only the max, but indicates something drawing too
much power. And the one where I have the FSM specifies a rather
beefy battery for the vehicle where 5 milliamps is the nominal
drain. Admittedly that same FSM recommends a low power external
charger if the vehicle is to be left for several weeks.
Tomcat14
The Mitsubishi in question above only was drawing 35MA in sleep mode
and the new battery is not going dead. The charging rate maintains 14V
all the way up past 50AMP output so I think that's all it was, just
the battery.
Charles Schuler
> No argument with your points... however, do you have an example
> of a car that actually draws 50 milliamp when there is NOTHING
> broken? And as important, what is the recommended battery for
> that vehicle? Did some engineer really screw the pooch there?
> I can come up with several instances of 5 milliamp, with notes
> that 20 is not only the max, but indicates something drawing too
> much power. And the one where I have the FSM specifies a rather
> beefy battery for the vehicle where 5 milliamps is the nominal
> drain. Admittedly that same FSM recommends a low power external
> charger if the vehicle is to be left for several weeks.
I found several on the web and have personally measured a few. Check
http://autorepair.about.com/library/faqs/bl283.htm
Steve
talk to about battery life. Remember, they start a car once every few
weeks and only run it for a few minutes to shuffle it around the lot or
maybe at most for a test drive- the battery never really gets re-charged
between discharges. Between that and turning on all the hazard flashers
as an advertising gimmick, its no wonder that they have lots full of
cars with perpetually dead batteries.
Lon Stowell
Thanks. Wow, 300 milliamp being the high side of nominal drain!?!
And without also specifying a huge reserve battery on the
vehicle, unless the new Jetta has a land yacht cadillac grade
battery standard. That really seems awfully high, wonder why
they don't drop the system into high impedance and use
[charged] caps to keep it alive for longer with way less
drain.
Gad, thought my Grand Cherokee Limited had gewgaws
in it, but it only drops 20 ma max after the 3 minute
standby period.
Charles Schuler
It's one of those obscure and neglected areas of engineering design. What
with all the law suits about exploding gas tanks and vehicle rollovers, it's
just not a high priority. Maybe if someone sues after being mugged because
their car wouldn't start it will be pushed up the list. We know about chips
with sleep modes and EEPROMs and other technologies that would allow the key
off static drain to be reduced to a few mA and so do the car makers. Some
have already made a few passes at it and some seem to be not too concerned.
It was good to keep this discussion alive since there is a lack of general
understanding in this area. I appreciate your input and that of others.
It's a great way to learn and share.
Jeff
Yea proably was, 95 year and back is more common
and they are in other vehicles also.(Mitsubishi built ECUs)
Just something else to look for if the draw is over specs.
Jeff
Bob Kos
draw system and tie other useful systems into it. Then the aftermarket
electrocrap will be piled high & deep into the vehicles rendering the zero
draw system useless or pointless or worse.
Lon Stowell wrote in message <3EFC989C...@attbi.com>...