so when im driving, and its in gear, the battery will stay around 12v. when i slow down, and let it idle, it gets closer to 8v and my headlights and all lights go dim. i switched batteries with my dads car, and it works fine. so its the battery right? well i put my battery in my dads car...and it works fine. stays above 12v, lights are fine at idle, starts easy. so could my alternator not be charging the battery? let me know if you need any more information...thanks



its a 82 with 160,000 miles, but the engine is from an 87 with 100,000. i dont know which one the alternator is from though...

 

CHeck the connections on your battery for corrosion, that is the probable cause on most battery problems. If that isn't the case, its either the battery or the alt.

 

absolutly no corrosion

 

Sounds like an alternator. test for voltage at battery should be at least 13 volts. of course test this voltage with both batteries and get battery on question tested.
batteries can really throw you for a loop sometimes, just go to auto zone or somewhere like that and have the charging system and battery tested. but don't buy one of their shitty batteries, you can get the same one from wal-mart for less, just a different label.

 

the easiest thing to do is take it to a parts store that does battery and alternator testing. they usually don't have to pull anything out of your car. you just start it up, then they hook some stuff up to your battery and then they tell you whats wrong. then they try and sell you whatever you need, but if it is your alternator, you can usually have them rebuilt for a lot cheaper than buying a new one.

 

the easiest thing to do is take it to a parts store that does battery and alternator testing. they usually don't have to pull anything out of your car. you just start it up, then they hook some stuff up to your battery and then they tell you whats wrong. then they try and sell you whatever you need, but if it is your alternator, you can usually have them rebuilt for a lot cheaper than buying a new one.

 

Have you EVER changed the battery cables? Even ones that look OK can have serious conductivity issues. Amazing how many electric gremlins vanish with a fresh set of cables. Victoria British sells a set for...$35? victoriabritish.com.
Stu Aull
80GS
Alaska

 

It would definitley be the alternator first, that would be my guess. Did you take your battery out and put it in your dads car, or take his battery and put it in your car?

 

i replaced my alternator when i had those same problems. now it stays steady at 12v.

 

i switched both, so the old battery now works fine in my dads car......i think.


and i took it into pep boys, they said it was a good battery, and recharged it. but they gave a a little thing that said my battery couldnt hold a charge, but when i put it back in it worked....

 

CONNECTIONS!!!

 

I got my battery from Autozone last year, and it ain't shitty. It holds charge perfectly and when I was having starting problems recently, I was able to crank the engine for about 10 minutes, almost non-stop!

 

First of all there's no such thing as "holding charge"
if it's not "holding charge" it's probably worn out, this means the battery dosen't have the reserve it used to.
(On some rare occasions I've seen batteries self-discharge at high rates, by this I mean new batteries that were shorted inside. not some 4 year-old battery someone is wondering why it won't charge up.)
This is really important for deep cycle batteries used for trolling or ups applications. My boss put really old deep cycle batteries in the company vehicles that weren't any good for cycling anymore but still would have the short cranking to start anything. Deep cycle batteries last much longer for this purpose because the plates inside are so thick. Cranking batteries have really thin plates so when they go-they go.


Most auto-parts stores sell the same battery just a different label (jci aka johnson controls), there's only one or two companies in the us that make batteries in the us. And new castle(turbo-start) is about to if not already stopping production, no one wants to buy quality batteries anymore. So that leaves one or none. American batteries are of much higher quality. Look at delco, they had their last plant in flint michigan close and now their quality is ****, they used to be the best. Ask anyone with a 2000 on gm truck or any other vehicle with a group 78. I've purchased cars with jci batteries already in them and never had a problem But I've Also spent some time in the battery industry and seen a lot of ****, I've seen brand new ever start's from wal-mart(jci) have dead cells in no time.
The place I worked for for a few years used to sell douglas batteries under the "astro lite" label, they moved their plant to mexico and the return rate went from less than 3% to more than 10%, and over 50% of batteries made in november of 1999 came back with dead cells. hence the term "dead cell douglas" lol
Never buy a douglas battery, Never buy an automotive battery from "batteries plus" they are all made by douglas. Absolute junk.

Many people think Interstate batteries are some haven of quality-Not True.
Interstate dosen't make any batteries, they sub the lowest bid, usally jci. People pay more than $100 for the same 50 month battery they could have gottan at wal-mart for 39.95 or less.

Optimas aren't worth the money, don't let anyone convice you otherwise. I might consider one if I had a civic, because they make a 51 now and nothing else fits there.
My advice, buy a sealed deep-cycle battery, group 22 or 24. If you live somewhere warm buy a sealed U1 (sealed version of lawn-mower battery used for wheel chairs etc).
I ran a wet U1 in my race car, 520 ca lawn mower battery, i think it weighed 18 lbs. I don't reccomend a wet u1 unless it's rated over 500 cranking amps, these are difficult if not impossible to find.

When buying a battery from somewhere like auto-zone or advanced look at the date on the side, it's a round two-color sticker. it will say something like A4(1-04 january 04) or B4 (2-04), etc etc I was in autozone the other day and their was a group 51 on the shelf that read C3, if you've figured this out you already know that this battery was sitting on the shelf for a YEAR!!!!
Do you think auto-zone looks at the batteries or even know's how old they are ? You think they charge them every couple months? NO! The next guy that buy's that battery for his civic or whatever other honda's a 51 goes in is going to get fucked, his battery is already a year old, it will still start his car, and probably last over a year but the life expectancy is much lower.I was in another auto-zone about a month ago and there was deep-cycle group 31 that was dated 1999!!! I really feel sorry for the guy that buy's that on the way to the lake to run his trolling motor. This battery did appear to have been charged, and the terminals had been cleaned but regardless....
If you are going to buy a cheap battery go to wal-mart, they usally have very fresh stock due to high volume, generally less than month old if not less for comman group sizes.

other maufacturers have different code dating systems, they're pretty easy to figure out if you look at few batteries.

With any battery always check the dates, when in question ask how old they are, see what response you get.

Sorry for the rant, just my $.02 on batteries.
Joe

oh yea 12 volts flat is dead. if the voltage is less than 12.5 the battery needs charging.

 

Thanks for that info.. that was some good stuff.