Car Battery Mystery

Last year I had my (proven trustworthy & good reputation) garage replace the original battery in my 1998 Lumina 3800 LTZ. The seven year old battery never was a problem but was load testing weaker and winter was close. Normally I do routine maintenance but the car needed new tires, alignment, and other work, so I had them do the battery, too.

Several months later in cold, February, temperatures, the car was harder to start after sitting, unused for several days. The starter almost stalled and was slower than I remember it being. This was a borderline occurrence and I wasn't absolutely positive a problem existed because the temperatures warmed up soon after.

This winter the car became hard to start and the starter would stall on first attempt after sitting outside overnight in zero degree temperature. This was never a problem so I took the car in to have the battery checked. The starter and alternator were new and their health was verified. Unfortunately, the battery load tested OK, although on the low end for a one year old battery. They are perplexed.

The one mile drive to the garage seems enough to have it pass load tests - they've done several. Next step is to drop it off at night and have them load test it outdoors before starting and to note how well it starts.

The battery voltage drifts to 12 volts or less after sitting unused for a few days, but no abnormal drain was evident. My hunch is a bad cell which isn't showing itself under these conditions and the garage tested all the normal suspects.

Any experts care to add a few cents worth? The battery has another six months of the 100% warranty. I'll appreciate any advice or further testing that I or the garage might do. They are GM certified and have experienced, long term, mechanics.

How many mA's were measured for your "no abnormal drain"?

<200mA

jayflash said:

<200mA

Click to expand...

That's kind of high, but it should still last at least 7 days before you have the above kinds of problems even with a marginal battery. Is this a sealed battery?

What voltage is your alternator charging at? A slightly low charge can cause similar issues to a dead/weak battery.

Alternator output is steady between 14.5 & 14.7v - pretty tight regulation even when loaded down.

The battery is sealed. It's an Interstate brand which has been all over the map regarding quality, IRRC.

Be sure to take care of the little things like making sure the terminals are clean and the cables are tight. You can even lose a charge if the battery tray is really cruddy. Checked the belts lately? A loose alternator belt won't help things.

Lastly, if it's not holding a charge and it's only a year old, find the warranty and take it back. Beats changing a battery in an old, rusty car when the weather is 10 degrees F and it's windy and starting to snow -- want to bet how I know all about that?

difinitely check all connections -- in fact, remove them, brush them (brass brush wheel on a drill works well for this) to a bright new-penny shine and reattach them snugly, (and coat with grease or vaseline or what have you)
and please advise to the following;
what kind of battery did you used to have?
what kind of sealed Interstate battery is it? AGM? Gel?
what was the temperature when it measured 12 volts outside?

could it be that the battery is not getting charged, ie you're not driving the car as much? or making more short trips, starting and stoppingthe engine more frequently?

did you get a smaller capacity battery than last time?

has it been colder than in the past? the temperature will decrease your starting capacity by about 10% per 15 degrees F below 68-77F (depending on manufacturer)

if it's a gell or even an agm battery 14.7 volts is the absolute limit to charging. if it really is charging above 14.7 you're gassing the battery and depleting it's capacity..this wouldn't have happened when you were using with a wet lead acid battery, if you were..well it does, but you add water periodically to a wet cell..

*

The only thing I can think of is one or more of the plates inside the battery might be damaged.

I had a battery a Canadian Tire battery that had a problem like that and we noticed after the battery vented blowing a hole in the side. The Alt also died because it was running for extended duties for too long.

You should be able to exchange the battery in a such a short period of time.

Ted already asked, but are you running more short trips not fully charging the battery?

Otherwise you could have gotten unlucky and got a weak cell. Otherwise I would put a good charger on it overnight to make sure it is fully charged.

The biggest factor in how 'good' a car batttery is is how long it has been since it was manufactured, accoring to Consumer Reports. The companies that manufacture batteries use codes for the manufacturing dates; and I don't know them.

Initial manufacturing quality isn't really a big factor: all the batteries sold in the USA are made by only three manufacturers. Gould is one ( I think they have a new name, and batts made by them have a three letter code beginning with 'G.' 'GBC'?) I can't remember the other two. This information comes from an older Consumer Reports article; and may be out of date; sorry.Anyway, according to CR, newly manufactured batteries of equal capacity are so similar they couldn't detect any statistically significant difference.

A dealership may have a battery sitting in inventory for far longer than 6 months. After 6 months (approx.) a car battery starts to break down, and it will never be a good battery. Precipitates form on the bottom of the cells and harden there; they will not go back into solution. Shorts between individual plates lower the capacity of the battery, and greatly shorten it's lifespan. Given enough time, one or more cells may actually die.

A fully charged battery should read exactly 13.2 volts when fully charged. Six cells, 2.2 volts per cell.

Like any rechargeable battery, just after charging, the voltage may read higher; this is called 'surface charge. This must be discharged to get an accurate reading.

Drive the car for 30 minutes, turn off the car. Turn on the headlights for 5-10 seconds to drain off the 'surface charge' and check the voltage. If it's not 13.2 volts, you have a problem. If it reads low, try charging it with a charger, with the negative terminal to the car disconnected.

If you charge the battery with a charger, and it doesn't read 13.2 volts, the battery is junk, and should be replaced under warranty. You should reconnect the terminal, and turn on the headlights for 5-10 seconds to drain off the 'surface charge'. Disconnect one of the terminals before taking a reading.

If it reads 13.2 volts off the charger, but lower when it's charged in the vehicle, the battery is OK, but you have a problem with the vehicle.

Good luck.

I was working with Johnson Controls on a project this past year I learned that they make MOST of the car batteries in the US, including AutoZone, Wal-Mart, Sears, Costco, Pep Boys, Interstate Battery and making the OEM batteries for chrysler, ford, toyota, honda, and nissan I believe, and the Optima line

just random trivia

The problem may be somewhere else than in battery. Are you sure that the wiring to the starter is ok? E.g. sometimes solenoids get oxidised and do not provide good enough electrical path to start the engine properly.

-N

Goldenlight may be on track in that after removing the "surface charge" the battery only has 12.3v after sitting overnight. After running the engine for 15 minutes with an initial charge voltage of 14.9 dropping to a steady 14.4v the battery only shows 12.9v after using the high beams.

The battery may have been old stock which could explain its behavior.

I used a more accurate meter to retest charging voltage. When the battery is partially charged, the charge voltage is initially higher than the normal 14.4v reached after a few minutes.

My background and employment is in the electrical field so I've tried to cover the basics and had the garage recheck. If the new starter or connections were bad it would show up in the current it draws. The problem only happened after the new battery was installed.

Thank you all for your assistance. Back to the garage we go. I'll have to sit with the mechanic and plug my meter in to prove my point, perhaps.

just a random idea

i wonder how many CR123 primaries or optionally 18650's we'd need to get enough amperage to start a car. It would be a damn nifty little emergency pack if small enough, and good for 10 years in the trunk

Sounds like the battery to me,their like everything else anymore CHEAP regardless of price.I would get another like you had.other than that,just like Flashlights,resistance fixes.

14.9 is too high a charge voltage for sealed batteries above 60F and much too high for sealed gel batteries. Unless the battery is really cold.
12.9 after a drain isn't shabby at all. normal resting voltage is lower than that, but tto get that figure you'd have to remove the battery from the car, let it sit 12 or 25 hours then measure it at 68 or 77 degrees F., (and who ever does that?) then it should be 12.6 - 12.9.. 12.9 while still in the car and just after a load is good, 11.9 would be good at 0F...
but if you have been regularly charging it at 14.9 or above you may have depleted the load capacity esp. if it's a gel..(but come to think f it a gel wouldn't work much at all below 32F..) so just a load tester can test it..

some good suggestions here, you only require a marginal cell to bring down a seemingly heathly battery, especially in the winter months when the electrical demand for starting is greater.. the internal resistance of a battery increases when its cold... coupled with an increase in oil viscosity just might be enough... athough from what ive read here you may have had a marginal battery from the kickoff
At 10.8v your battery is completely discharged... so it doesnt take a great deal.. overcharging is just as bad & will sulphate the batteries plates..

also if its a sealed type do you have a plastic window in the top showing the 'state of charge' usually green for OK.. what does it look like ( if you have one - window that is)

It's a normal wet cell and the 14.9 charging volts were only right after starting at 10F outdoor temperature where the car sits. It went down to 14.4v after a minute or so and holds regulation pretty well at various RPMs and electrical loads.

I parked the car outside at the garage yesterday so it would sit in the cold (zero deg. F. last night) overnight. They're going to retest it this AM. At this point I'm still suspecting a weak cell. Of course other problems can imitate a bad battery but we've tested for them - hopefully the starter and cable checks were accurate.