iffy battery of ???

[pasadena_commut]

Today after parking at work I realized one of the windows was down. Tried to turn the car back on (by just turning the key, no gas applied) and the motor didn't start, or even turn over, although the dash lit up. Tried it a couple of times and then pushed the gas once while in the "start" position and it started right up. It has been hot the last few days, over a 100, so a cooked battery is definitely a possibility. The gas thing is odd though, usually my car starts without having to press the accelerator.

Later this morning I will go out and measure the battery voltage and check the oil.

Any ideas what else this might be?

 

[Deleted58156]

the does sound kinda odd, but i could be that your charging system is having a hard time. I say this because to my knowledge, i've only heard of battery's dying in the extreme cold, not hot.

 

[slavrenz]

the does sound kinda odd, but i could be that your charging system is having a hard time. I say this because to my knowledge, i've only heard of battery's dying in the extreme cold, not hot.

Hot weather kills batteries a lot quicker than cold weather. To the OP, check your battery voltage and then repost.

 

[pasadena_commut]

Hot weather kills batteries a lot quicker than cold weather. To the OP, check your battery voltage and then repost.

Just sitting there, no load, it was 12.59V which is about 75% charged. Turning on the headlights (not the brights) caused it to drop immediately to 11.74 volts and it fell from there at about .01 volts per second. I could not test how low the voltage went when the motor was turning over since I was working alone and didn't have a clamp on voltmeter. The battery was installed in 2005 and that's about it for a battery in LA. Since I had an appointment to get to this afternoon I took the morning off and changed the battery. All the local Pep Boys had in that size was a Bosch. Put it in, and the car starts up fine. I will check the voltages on it over the next few days - if the charging system is going it should be obvious.

The Bosch is a little shorter than the battery I had in there, so I had to put a stack of washers under the tightening nut on the battery clamp and crank away to lock the battery in place. The near side of the battery clamp is nowhere near the battery. This will do for now but it isn't ideal. Anybody have a better solution?

Also, what is the proper torque for the nuts on the front sway bar?

 

[slavrenz]

Just sitting there, no load, it was 12.59V which is about 75% charged. Turning on the headlights (not the brights) caused it to drop immediately to 11.74 volts and it fell from there at about .01 volts per second. I could not test how low the voltage went when the motor was turning over since I was working alone and didn't have a clamp on voltmeter. The battery was installed in 2005 and that's about it for a battery in LA. Since I had an appointment to get to this afternoon I took the morning off and changed the battery. All the local Pep Boys had in that size was a Bosch. Put it in, and the car starts up fine. I will check the voltages on it over the next few days - if the charging system is going it should be obvious.

The Bosch is a little shorter than the battery I had in there, so I had to put a stack of washers under the tightening nut on the battery clamp and crank away to lock the battery in place. The near side of the battery clamp is nowhere near the battery. This will do for now but it isn't ideal. Anybody have a better solution?

Also, what is the proper torque for the nuts on the front sway bar?

12.59 volts is exactly what it should be for just sitting there (that is fully charged, not 75%), although it sounds like it was still defective since it apparently couldn't hold the charge once a load was applied.

If you want to check your charging system, measure the voltage at your battery terminals with the car running. It should be about 14.5 volts.

 

[SocialStealth]

I would defiantly have your alternator tested, they tend to last 10 years or less.

A bad alternator will kill your new battery....
A bad battery will kill your alternator...

So they both tend to go bad at the same time.
Your old bat probably did some harm to your alt, that is if your alt didn't do the harm to your battery.

 

[pasadena_commut]

12.59 volts is exactly what it should be for just sitting there (that is fully charged, not 75%), although it sounds like it was still defective since it apparently couldn't hold the charge once a load was applied.

Oops, you're right, I omitted part of the description. It was 12.59V when I got to the car, with (some) surface charge on the battery. Turned the headlights on for a few seconds, then off again, and it remeasured at 12.46V (where it was stable). 12.46V is 75% charge.

 

[Deleted58156]

Hot weather kills batteries a lot quicker than cold weather. To the OP, check your battery voltage and then repost.

my bad partner i forgot to take into consideration sulfation in hot weather, which can ruin crank and deep cycle power....

 

[pasadena_commut]

my bad partner i forgot to take into consideration sulfation in hot weather, which can ruin crank and deep cycle power....

Its usually simpler than that - the heat dries out the battery. Even the sealed ones will evaporate away their water eventually, and being sealed, there's nothing you can do to rehydrate them.

 

[slavrenz]

I would defiantly have your alternator tested, they tend to last 10 years or less.

A bad alternator will kill your new battery....
A bad battery will kill your alternator...

So they both tend to go bad at the same time.
Your old bat probably did some harm to your alt, that is if your alt didn't do the harm to your battery.

Explain to me how a bad battery can ruin an alternator...(eyeballs)

 

[MS3_KIDD]

Explain to me how a bad battery can ruin an alternator...(eyeballs)

the alternator or generator in the field will want to charge the battery anc cause it to ge full fielded at all times for maz out put

this will eventually causer the generator to commit suicide

 

[slavrenz]

the alternator or generator in the field will want to charge the battery anc cause it to ge full fielded at all times for maz out put

this will eventually causer the generator to commit suicide

While that can theoretically happen, for 99% of people, they aren't going to run their vehicle with a dead battery for that long. I'm thinking that after 5 or 6 jump starts they might start thinking about replacing the battery

 

[MS3_KIDD]

you'd be surprized

i see it all the time at the shop i work at

 

[i12drivemyMP5]

Walmart everstart - 3 yr full replacement, 8 yr prorated replacement for 70.00. Same size 35 series that came in it to begin with.

 

[slavrenz]

you'd be surprized

i see it all the time at the shop i work at

If that's the case, then I think those alternators were on their last legs anyways.

 

[MS3_KIDD]

If that's the case, then I think those alternators were on their last legs anyways.

not necesarly

when you put the kind or stress on a charging system that is pushing its capabilitys for longer than normal amounts of time

ex: recharging after a hard cold start, versus a battery with 1 dead cell with 10.5v causing the generator to be full fielded 100% of the time

excessive heat from the constant high charging output demand kills the generator

 

[SocialStealth]

not necesarly

when you put the kind or stress on a charging system that is pushing its capabilitys for longer than normal amounts of time

ex: recharging after a hard cold start, versus a battery with 1 dead cell with 10.5v causing the generator to be full fielded 100% of the time

excessive heat from the constant high charging output demand kills the generator

Correct,
The battery, even if it doesn't need to be jumped, if its constantly low it will over heat/over work the alt.

You'll want to have your alt load tested. However, often the auto-store tests (which are usually free) will not prove to be accurate.

If your alt is damaged, it will charge your new battery incorrectly and drastically shorten its lifespan.

 

[MS3_KIDD]

or even worese, heres what i been working on lately

i wont name a vehicle because the brand doesnt change any thing, this can still happen


intermitantly driver complains of hesitation, stumbling when trying to accelerate, poor drivablity, vehicle on its 4th battery and 3rd alternator, had multiple sets of injectors done, etc

turns out that it wasnt intermitent, it was only when he had his system cranked up, 850-1000 watts i think it was

when ever he had the system on, it was creating to large of a demamd on the battery and charging system, causing the diodes in the rectifier bridge of the generator to opening up allowing the battery to be charged with AC voltage, causing voltage spikes in circuits, shorting fuel injectors, and damaging the battery and charging system

all batterys recieve some amounts of A/c Voltage from the generator but the demand he was putting on the car was beyond normal conditions

 

[pasadena_commut]

You'll want to have your alt load tested. However, often the auto-store tests (which are usually free) will not prove to be accurate.

So which test is the appropriate one?

There is no obvious problem with this alternator. The voltage on the new battery when the car was off overnight was 12.75V (without doing anything to eliminate surface charge). So driving it on two very hot days did not run it down. With the car started (cold) the voltage rose quickly to exactly 14.0V and stayed there, only varying by around .01V. Which is all pretty much as it should be for a new battery and a working alternator.

I have never experienced a heat killed battery (the usual cause of battery death here in LA) damaging an alternator. Probably this is because the battery fails relatively quickly to the point where it cannot start the car. Consequently there is only a limited time where the alternator is miore heavily loaded, so it is not damaged. Another way to think about it is that a battery has (essentially) a resistor between its two connectors, and when healthy, that resistor has a very high value. As the battery fails the resistance decreases. A resistance small enough to drain the battery in a few hours and cause starting problems pulls about as much current as leaving the headlights on, which is well within the capacity of the alternator.

 

[youngbull]

a battery is a chemical reaction. set to be used optimally at a set temp range. going outside those ranges, really hot or really cold can cause it to fail. basic chem says reactions happen faster at high heat, which doesnt mean more usable power. but can cause the surface of the batt plates to sufate too fast which stops the reaction.

and store tests do not always take into account amperage which is usally the part that fails on the alt. still can put out volts but not amps which is what charges the batt