Car Battery Question....

[Floppyman]

Hi all,

I fired up my car this morning and it cranked pretty slowly (almost as if there wasn't a lot of juice left in the battery), but it turned over right away. I had to some shopping in a bigger city about 25mi away so I had a dealer check the battery out quickly. The battery is rated for 675 CA (Cold Cranking Amps), and when it was tested (after the half hour drive to the dealer) it came back as 512CA, needing recharge but GOOD result. The service tech told me I just needed to drive my car, or maybe put in on a charger to recharge the battery if not that. The weather around here has been pretty cold lately. Highs in the single digits with windchill's pushing things 10 to 20 below zero. At college the car can sit at times for a couple weeks without being driven, but I had just driven it the day before. What do you guys think? Was the tech right and I don't have to worry, or do you think the battery might be on its way out? If not, what are some of the telltale signs (beside a battery not holding charge) that foreshadow a car battery going dead? I know some of you guys are car buffs so I'd appreciate your input. Thanks in advance.

[bailey]

I would with out hesitation go for a new battery.
usally it is one of the first signs of it getting ready to retire, and this is not the time of year that you want to be cought with a dead battery.
there will be a lot more load on it this time of year with the lights, wipers and heater all running and it is better to be safe than sorry.

[Byte 2.0]

I agree with bailey on this.

When I have a battery that goes almost dead on a cold night, Off to autozone I go.

BTW I put the highest cracking amp i can in my cars, like 975 normal 800 cold or some crazy hi number.

[mc2phat]

I will agree with these gentlemen in your situation. I have a shop and a couple good trickle chargers that I could use if I was in a similar situation. You need your car to start, and having to replace a dead battery early one morning would cause undue hardship that spending fifty bucks now would prevent. IMO, cheapo batteries (i.e. Wal-Mart brand) last 2 - 2 1/2 years, good brands like Interstate or AC Delco last twice that. That's with regular maintenance. Another thing to consider with a vehicle sitting for so long without being driven is the possibility of condensation in the exhaust causing rust & the exhaust needing replaced sooner. If you drive it 60-70 miles at a stretch usually this won't happen.

[Floppyman]

Thanks for the input fellas. Looks like I'll be off to buy a new battery tomorrow. I've never put one in myself (sad, I know, but hey), so would it be best to go ahead and buy one and have a local shop install it for me? I know it's not quite as easy as just disconnecting and putting a new battery in with all the computer stuff cars use nowadays. Or should I go to a dealer directly (which will probably end up being more expensive)? Thanks in advance.

[bailey]

I belive autozone and other places will install it for you free.
and yes you will loose any data that may be in the computer, and the clock and radio settings too.
but that is ok it will not degrade anything for you. the dealership would be the last and most expensive place to go.

[HAL9000]

How about a more simple solution... check your belts. It might be slipping just enough on the alternator to not be getting enough of a charge. Or alternatively (no pun intended), get your alternator checked to make sure it's putting out enuf juice, mebbe the weak battery is a sign of low output on the alternator.

[Floppyman]

Thanks for the reply bailey. I'll have to see if there is an autozone or similar near me where I can get this done. I was looking at batteries.

This Interstate one looked nice:

http://www.ibsa.com/estore/view_prod...2KEHFAX6F&js=1

And then there are these ACDelco's:

http://www.acdelco.com/html/pi_batt_main.htm

Is any brand better than the other? Which ACDelco series would you guys pick? The Interstate is an 85 months battery and ACDelco also makes one that's close to 7 years. Thanks again for your help.

[Floppyman]

Originally Posted by HAL9000 How about a more simple solution... check your belts. It might be slipping just enough on the alternator to not be getting enough of a charge. Or alternatively (no pun intended), get your alternator checked to make sure it's putting out enuf juice, mebbe the weak battery is a sign of low output on the alternator.

Are there any other signs that you can look for to see if the alternator is not working properly? Thanks again.

[HAL9000]

OK... this may sound funny... but it's a neat little hack method that works quite nicely... start your car and hold the end of a screwdriver to the back bearing on the alternator. There should be a fairly strong magnetic pull.

[Floppyman]

Originally Posted by HAL9000 OK... this may sound funny... but it's a neat little hack method that works quite nicely... start your car and hold the end of a screwdriver to the back bearing on the alternator. There should be a fairly strong magnetic pull.

Thanks Hal. Are there any more obvious ways to tell that the alternator may be going bad? E.g. dim driving lights, etc...?

[bailey]

ok, you asked for it:
autozone will also connect a special tester that will test all the functions of the alt, and also test the battery, and for free too.
I had mine done there last month.

[lil Jimmie]

Batteries die most often when the temps change to very cold or very hot. If you have a volt meter you can check the voltage output while the engine is running w/ lights on the voltage at the battery should be between 13.75 to 14.25. If the car won't start and you throw the volt meter on the battery and the voltage is below 11.50 get a new one. Make sure the posts and cables are clean, corrosion can cause cranking and charging problems as well.

Interstate make a good product.

FYI I will not warrantee the labor to my customers for installing any product sold by AutoZone. I like to do the job once.

[Floppyman]

when the tech tested in it came back as 12.45V, 512CA (of course with the engine off). Is that normal, or not? Thanks again, guys.

[lil Jimmie]

I'd rather see what the voltage is running with a load and after it has sat idle for 24 hours.

[DragonNOA1]

You have to run your car at least once a week, drive it for 5 minutes on the highway, bring it back and park it for another week.

But the biggest Gold series DieHard battery, you thank yourself with this cold weather we have now. And yes, AutoZone or Advanced Auto... places like that should install the battery for free. Just mention it to them and they should.

I forget what mine is but it can definately go higher than the 500's for cranking amps.

And a few days ago it was like in the negatives (outside temp) and my car turned slow at first then fired right up. I'm not worried about a battery tho, it was colder than crap!

[Byte 2.0]

autozone and places like that will normally test the alternator for free as well. They offer free installs as well normally. I have never had them test any of mine as I kind feel they will probably try to sale me one, but for pace of mind they can do it.

[Floppyman]

Thanks guys. I'm just going to drive up to a local shop in town tomorrow and have him check things out (alternator et all). In the worsy case, I'll just bring it there have it sit a couple hours and have him start it cold to see if there is indeed a problem with the battery. Personally, I think it's going out but we'll see. Thanks for all the help so far guys.

[colecifer]

I'm a little confused, i don't know much about cars just some random things. I thought that all your battery did was send power to the alternator to start the car and then get recharged by the alternator. I thought that the alternator then did all the work from there. You guys are confusing me though with all your talk about the stress lights and the heater put on the battery. Can someone please explain.

[i8uiky]

colecifer the battery sends power to the starter to start the car then the alt is supposed to supply all the power to run all excessories(lights, radio, heater...) and recharge the battery.

[bailey]

and when you do a lot of stop and go city trafic, you can draw more amps than the small alt that most cars have, which can draw more from the batt than the alt can supply, most cars only have a 25 to 30 amp alt and that is not at a idle speed.

[HAL9000]

You want CC Amps... every time I need to get a battery for a car... I buy one of the 1000-1300 CCA batteries at Canadian Tire... no problem starting my car.... ever.

[lil Jimmie]

The battery supplies the initial power to start the car and the alternator maintains the voltage at or around 13.50-14.25 to charge the battery, run all lights, fans, windows and power seats.. yada.. yada... By the voltage running slightly higher than 12.50 volts it keep dips in voltage from interfering with the ECM and other vital sensors from reporting erroneous voltage to the ECM when supply is needed for other components and charges the battery.

Load tests while running ensure that the alternator is doing it's job, letting the battery set over night will determine if the battery will hold a surface charge.

One other thing to consider is the possibility of a current draw which a good tech should check once the battery and alt are found to be good and the problem persist.

most alternators I see are 45-60 amps

[Floppyman]

Originally Posted by bailey and when you do a lot of stop and go city trafic, you can draw more amps than the small alt that most cars have, which can draw more from the batt than the alt can supply, most cars only have a 25 to 30 amp alt and that is not at a idle speed.

Ah I see, makes sense as the alternator is also belt driven. So the higher the rpm, the more electricity the alternator can produce (up to a certain point), right?

[bailey]

that is correct, they are really supposed to deliver the full amps at idle, but in reality, they don't always do what there supposed to do, if the idle rpm of the engene is correct, it should work ok, but as the load on the alt is increased, so is the load on the engene, and the rpm can drop some, and when that happens so does the output of the alt,
so there is a number of things that can afferct it, and the test that are performed will usally detect where the problem lies, and the problem will be corrected. even as mentioned earler, a loose or worn belt can do it too.

it is always best to replace the battery every so many years anyway.

[colecifer]

I'm still a little confused, what i was saying earlier is correct though right? Thats the impression i got. Like i said i don't know a whole lot about cars. If something happens i can usually get an idea of whats wrong with it after some looking around, but thats more of a point to something and say i think that thingy is messing up that thingy which makes your car not work. So obviously i'm not much of a gear head.

[Floppyman]

Originally Posted by colecifer I'm still a little confused, what i was saying earlier is correct though right? Thats the impression i got. Like i said i don't know a whole lot about cars. If something happens i can usually get an idea of whats wrong with it after some looking around, but thats more of a point to something and say i think that thingy is messing up that thingy which makes your car not work. So obviously i'm not much of a gear head.

Yes, pretty much you are correct. However, at a given rpm the alternator can produce only so much electricity (current) -- rememeber it's belt driven by the engine just like a supercharger. So if you do a lot of stop and go driving (i.e. a lot of idling at stop lights) and have your heater running fullcore, radio blaring, windshieldwipers, and lights on, the alternator may not be able to produce quite enough, so the extra juice needed can only come from the battery.

That's why these guys suggested I take a look at the alternator in my car. If it's not working correctly (and not producing enough current when it should be), that could be what is running down my battery.

[colecifer]

Ok, i understand now. Thank you floppy man.

[bailey]

Originally Posted by colecifer I'm still a little confused, what i was saying earlier is correct though right? Thats the impression i got. Like i said i don't know a whole lot about cars. If something happens i can usually get an idea of whats wrong with it after some looking around, but thats more of a point to something and say i think that thingy is messing up that thingy which makes your car not work. So obviously i'm not much of a gear head.

you can look at it this way, the output of the alt is connected to the battery, and all the load is connected to the battery too.
so say you have a 30 amp load and you are driving down the freeway at 70 mph, the alt may be delivering a 40 amp currant to the battery, the 30 amps will supply the load and the extra 10 amps will go into charging the battery.
then you get off the freeway and get to a traffic light, now the alt will only deliver 25 amps at engen idel, but the load is still 30 amps, so now you are drawing the extra amps from the battery to supply the same load, which is more than the alt can deliver. if you continue this for X amount of time, the battery will go dead,

[glc]

If the battery is more than 3 years old, replace it on general principle. When was the last time you got the oil changed and what weight oil is in it? Thick oil will cause slow cranking - in this weather you should be using nothing heavier than 5W30 in a modern car with an engine in good mechanical condition and less than 100K miles on it.

I was over at Sam's Club buying tires a couple of weeks ago - noticed that they sell Interstate batteries now, and they do install them.

Wherever you get your battery and have it installed, make sure they use a parallel battery setup to preserve the computer memory. Any reputable shop that replaces batteries should have something for this.