What Causes Car Batteries to Fail?

Driving habits rather than battery defect are often the cause of battery failure.

A German manufacturer of luxury cars reveals that of 400 car batteries returned under warranty, 200 are working well and have no problem. Low charge and acid stratification are the most common causes of the apparent failure. The car manufacturer says that the problem is more common on large luxury cars offering power-hungry auxiliary options than on the more basic models.

In Japan, battery failure is the largest complaint among new car owners. The average car is only driven 13 km (8 miles) per day and mostly in a congested city. As a result, the batteries will never get fully charged and sulfation occurs. The batteries in Japanese cars are small and only provide enough power to crank the engine and perform some rudimentary functions. North America may be shielded from these battery problems, in part because of long distance driving. 

Good battery performance is important because problems during the warranty period tarnish customer satisfaction. Any service requirement during that time is recorded and the number is published in trade magazines. This data is of great interest among prospective car buyers throughout the world. 

Battery malfunction is seldom caused by a factory defect; driving habits are the more common culprits. Heavy accessory power when driving short distance prevents a periodic fully saturated charge that is so important for the longevity of a lead acid battery. According to a leading European manufacturer of car batteries, factory defects amounts to less than 7 percent.

The battery remains a weak link and the breakdowns on 1.95 million vehicles six years or less are as follows:

52% battery
15% flat tire
8% engine
7% wheels
7% fuel injection
6% heating & cooling
6% fuel system

A breakdown due to the battery remains the number one cause.

* Source ADAC 2008 for the year 2007

Acid stratification, a problem with luxury cars

A common cause of battery failure is acid stratification. The electrolyte on a stratified battery concentrates on the bottom, causing the upper half of the cell to be acid poor. This effect is similar to a cup of coffee in which the sugar collects on the bottom when the waitress forgets to bring the stirring spoon. Batteries tend to stratify if kept at low charge (below 80%) and never have the opportunity to receive a full charge. Short distance driving while running windshield wiper and electric heaters contributes to this. Acid stratification reduces the overall performance of the battery.

Figure 1 illustrates a normal battery in which the acid is equally distributed form top to bottom. This battery provides good performance because the correct acid concentration surrounds the plates. Figure 2 shows a stratified battery in which the acid concentration is light on top and heavy on the bottom. A light acid limits plate activation, promotes corrosion and reduces performance. High acid concentration on the bottom, on the other hand, artificially raises the open circuit voltage. The battery appears fully charged but provides a low CCA. High acid concentration also promotes sulfation and decreases the already low conductivity further. If unchecked, such a condition will eventually lead to battery failure. 

Figure 1: Normal battery
The acid is equally distributed from the top to the bottom in the cell and provides maximum CCA and capacity.
Figure 2: Stratified battery
The acid concentration is light on top and heavy on the bottom. High acid concentration artificially raises the open circuit voltage. The battery appears fully charged but has a low CCA. Excessive acid concentration induces sulfation on the lower half of the plate
s.

Allowing the battery to rest for a few days, applying a shaking motion or tipping the unit over tends to correct the problem. A topping charge by which the 12-volt battery is brought up to 16 volts for one to two hours also reverses the acid stratification. The topping charge also reduces sulfation caused by high acid concentration. Careful attention is needed to keep the battery from heating up and losing excessive electrolyte through hydrogen gassing. Always charge the battery in a well-ventilated room. Accumulation of hydrogen gas can lead to an explosion. Hydrogen is odorless and can only be detected with measuring devices.

The challenge of battery testing

During the last 20 years, battery testing lagged behind other technologies. The reason: the battery is a very difficult animal to test, short of applying a full charge, discharge and recharge. The battery behaves similar to us humans. We still don't know why we perform better on certain days than others.

Even by using highly accurate charge and discharge equipment, lead acid batteries produce disturbingly high capacity fluctuations on repetitive measurements. To demonstrate the variations, Cadex tested 91 car batteries with diverse performance levels (Figure 3). We first prepared the batteries by giving them a full charge and a 24-hour rest period. We then measured the capacity by applying a 25A discharge to 10.50V or 1.75V/cell (black diamonds).

This procedure was repeated for a second time and the resulting capacities were plotted (purple squared). This produced a whooping +/-15% variation in capacity readings across the full population. Some batteries had higher readings the second time; others were lower. Other chemistries appear to be more consistent in capacity readings than lead acid. 

Figure 3: Capacity fluctuations. Capacities of 91 car batteries measured with a conventional discharge method show a fluctuation of +/-15%.

From the beginning, load testers have been the standard test method for car batteries. The year 1992 brought us AC conductance, a method that simplified battery testing. Now we are experimenting with multi-model electrochemical impedance spectroscopy (EIS) in a portable version at an affordable price.

Getting a fast and dependable assessment of a failing battery is difficult. Most battery testers in use only take cold cranking amps (CCA) and voltage readings. Capacity, the most important measurement of a battery, is unavailable. While taking the CCA reading alone is relatively simple, measuring the capacity is very complex and instruments offering this feature are expensive. 

The Spectro CA-12 by Cadex Electronics is the first in a series of high-end battery testers capable of measuring capacity, CCA and state-of-charge (SoC) in a single, non-invasive test. The technology is based on multi-model electrochemical impedance spectroscopy (EIS). The system injects 24 excitation frequencies ranging from 20 to 2000 Hertz. The sinusoidal signals are regulated at 10mV/cell to remain within the thermal battery voltage of lead acid. This achieves stable readings for small and large batteries. 

During the 30-second test, over 40 million transactions are completed. A patented algorithm analyses the data and the final results are displayed in capacity, CCA and state-of-charge.

EIS is very complex and until recently required dedicated computers and expensive laboratory equipment, not to mention chemists and engineers to interpret the readings. The hardware of a full EIS system is commonly mounted on racks and the installation runs into tens of thousands of dollars. 

The tough choice

No battery tester solves all problems. Entry-level testers are low cost, simple to use and capable of servicing a broad range of batteries. However, these units only provide a rough indication of the battery condition. A lab test at Cadex demonstrates that a battery tester based on EIS is four times more accurate in detecting weak batteries than AC conductance. Conventional testers often misjudge the battery on account of low state-of-charge. Many batteries are replaced when they should have been recharged, while others are given a clean bill of health when it should have been replaced.

Acid stratification is difficult to measure, even with the EIS technology. Non-invasive testers simply take a snapshot, average the measurements and spit out the results. Stratified batteries tend to show higher state-of-charge readings because of elevated voltage. On preliminary tests, the Spectro CA-12 also shows slightly higher CCA and capacity readings than normal. After letting the battery rest, the capacity tends to normalize. This may be due to diffusion effects in the stratified as a result of resting. Little information is available on how long a stratified battery needs to rest to improve the condition, other than to note that higher temperatures will hasten the diffusion process.

Ideally, a battery tester should indicate the level of acid stratification; sulfation, surface charge and other such condition and display how to correct the problem. This feature is not yet possible. Much research is being done in finding a solution that offers a more complete battery evaluation without the need for a full discharge. The knowledge gained on lead acid batteries can then be applied to other battery systems, such as traction, military, marine, aviation and stationary batteries.

Comments

On December 15, 2010 at 10:12am
jerry White wrote:

i have not read anything this thorough in any auto service magazine or training manual in decades.  Congratulations on a great presentation of a complex subject.

On January 25, 2011 at 7:32am
Stefanie H. wrote:

I have a Lexus and drive short distances every couple of days. Once a month I may go on a longer trip. Is this enough to charge my battery? I didn’t realize that the further you drive the more charged your battery is. That sounds silly but I guess I never thought of it. Stefanie H.

On April 11, 2011 at 3:15pm
Al Miller wrote:

What causes a battery to pass the voltage test with no load and then fail when a load is put on the battery?  Is sulfation the culprit?  Is this what used to called “dead cells?”

On April 30, 2011 at 8:56pm
tye wrote:

The 30 year old truck only gets driven 2x/month 20 miles or less
The truck turns over but wont start.
could the 4 yr old battery that was tested & showed low cca (about 250 instead of 650) be charged back to normal? 2-3 of the cells were also low on fluid.  What causes the cells to lose acid?

.

On September 5, 2011 at 4:27pm
rex wrote:

i have a nissan sentra 1998 super saloon and i encountered a problem once when i did not start my vehicle for 2 weeks. it just crank and the remedy that i make is to jumpstart the vehicle then it when okay. if you do not use or even warm up your car every week i think you are in deep trouble. lots of rust also pilled up in my coolant tank.

On September 5, 2011 at 4:35pm
ronie wrote:

so i am not the only one experiencing problems with clogging of rust in my coolant tank.

On January 24, 2012 at 3:03am
Rainer wrote:

A very good article. But I miss a solution of this problem. Please allow me to mention one solution that I provided as a OEM in cooperation with a major German battery manufacturer. My company developped a system providing a small air pump sitting on top of the battery connected by tubes with every battery cell. Thus the acid was stirred by ais bubbles avoiding stratification while charging or in operation. For big batteries such as floor transportation carts we provided pumps with integrated electronic control unit with microprocessor. These units had a port to read out system up time, system down time, number of chargings etc.for more information don’t hesitat to contact me.

On January 24, 2012 at 11:46pm
Hank wrote:

Also understand that your charging system is not designed to charge a dead battery. if you jump start your car driving it around will not charge the battery properly and youll only be wearing out your charging system. After jump starting a car The battery needs to be charged on automotive battery charger. Equality battery charger will usually cost at least 100 dollars. Box stores sell inexpensive battery chargers that are charging at 2 to 3 amps after only 15 minutes. That is so the battery will not experience gasification. and blow up your garage, etc. Fast charging is very harmful to batteries.It is best for discharge battery to be charged for 2 to3 hours. Hope This helps.

On January 26, 2012 at 1:21pm
Bill wrote:

Hello, My 2004 Toyota Tundra is making me crazy!  It starts and runs well for a month or so and then I’ll try to start it and all it does is go, “click, click, click” over and over. The battery is fully charged by the way and my horn and other accessories still function as they’re supposed to? I have undone and re-tightened the cables a number of times and even bought new cables and installed them?
Maybe I’m way off here but my thought process now leans toward the steering wheel or gear shifter? Could that possibly be the problem?

On January 30, 2012 at 7:23pm
meaty wrote:

Well batteries really wear out and that is normal to any <a >car</a>

On February 8, 2012 at 10:38am
Fred wrote:

I have a battery I currently am trying to revive it with a BatteryMinder charger/maintainer/ desulphator-conditioner.  After two weeks, I have four well-charged cells and two that are dead.  Because the battery is from a car that I bought used, I do not know if it ever went low on water. 

I am intrigued by Rainer’s air bubble solution to stratification.  Can I accomplish the same thing by using a bicycle pump and a piece of plastic tubing to stir up the acid in the bad cells?

Also, how can I contact Rainer?

On February 9, 2012 at 5:32pm
anonymous wrote:

I was told by my car dealership that my car battery had a short in it. can a car battery have a short in it?

On February 17, 2012 at 10:19am
James wrote:

How about just a simple fish tank type air pump maybe $10-15 since you can control the amount of air with a simple plastic valve that is connected to the air hose. I think this would work or do it to!

On March 11, 2012 at 7:39pm
John Smith wrote:

I have a battery that was loosely connected to the terminal. I drive short distances on the weekend and during the week I drive 12 miles back and forth to work. Is this enough to charge my battery?

A local auto store tested mine a couple months ago and it was at 76% according to them. Today it wouldn’t start I took it out to look at it and charge it, then put back on the connector and it started back up. I also shook up my battery a little bit.

it’s only 2 years old, does shaking it hurt it? Also, is it possible for my battery to get back up to 100% again?(Assuming it was a bad terminal connection)

Thanks,
John

On March 19, 2012 at 3:31pm
Terry wrote:

I purchased a new battery for my 1987 190E Mercedes Benz 2.6 on Sept. 8, 2011 and it went dead on March 15, 2012. I took the battery back to O’Rielly’s Auto parts on a warranty and all they did was recharge my battery. How long will this battery stay charged?

On September 5, 2012 at 11:52pm
High Frequency Trading wrote:

Wow! I need to say. Actually not often do I encounter a weblog that is both educative and entertaining, and let me let you know, you’ve hit the nail on the head. I am hoping the same high-grade blog post from you in the upcoming as well.I agree that a web designer must have a creative approach and must have a understanding user. 

   
  Regards:-
High Frequency Trading

On December 15, 2012 at 6:44am
James wrote:

Well, its about time that battery manufactuers sorted these problems out.  If drivers are predominately using vehicles for short trips and low recharge cycles and the battery is becoming stratified then that’s the way we use our cars.  The batteriy and alternator manufatuers need to bang there heads togeather and sort the problem and not expect us to alter our driving habits to suit their outdated equipment!  I too have to charge my battery once a month to keep it ‘charged’... I also give it a good shake to stir the battery acid juice.
WE SHOULD NOT HAVE TO DO THIS!

Perhaps the battery fluid cycler would be an idea (but expensive to instigate)

On March 10, 2013 at 5:02am
Inus wrote:

Hi Bill,

Your Toyota Tundra is equipped with a v8 diesel ? Petrol. I would have the starter motor checked out. The buses tends to wear out check them for play. It needs to be a tight fit.Also inspect for lubricant that has become gooey. Alternatively the solenoid contacts tend to burn or even burn away which in turn resist / block the battery current from turning the motor. Make sure that the battery terminal clamps inside is properly cleaned with baking soda and hot water. Hope it will help.

On April 17, 2013 at 11:28pm
Alwis wrote:

i have a 2007 toyota kdh220. I didn’t start it in nearly 3 or 4 days. So now i try ane it didn’t start. Only had a ‘click’ sound. So is rainer’s method suitable for this? Then can you explain me to how i do it with my small fish tank air motor.

On June 22, 2013 at 9:28pm
Helenjerry wrote:

I always forget either spare clothes or wipes! And of course, whatever I forget is what I end up needing!

On September 11, 2013 at 3:53pm
Charley J. Wagner wrote:

Question, can any conditions exist in a cars electrical system that will completly kill a battery.  Not drain it so it can be recharges but totally destroy the battery.

On December 31, 2013 at 10:36am
John Dawson wrote:

I installed a new battery. The vehicle started several times. When left overnight
would not start. I noticed when I installed battery connections there was a large
spark. Volt meter on dash shows 14-15 volts which should tells me the alternator
is working. What should I look for?

On February 10, 2014 at 7:27pm
Dennis Burton wrote:

If vehicle is standing for longer than 5days best to disconnect battery terminals which should prevent discharge.How long can a battery last if topped up with tap water?

On March 18, 2014 at 11:01pm
Creative Web Systems wrote:

I am hoping the same high-grade blog post from you in the upcoming as well.I agree that a web designer must have a creative approach and must have a understanding user.

On March 21, 2014 at 5:03am
southernbatteries wrote:

I go through your website it’s very good and having good information about the Lead acid battery manufacturers, and we are also having similar website you can visit us.

Lead acid battery manufacturers

On March 25, 2014 at 6:56pm
James Powell wrote:

Had my car radio, taken out for repair { CD player }, car would not start next morning.  Car dealer put in new battery and three days later it did not start again

On March 25, 2014 at 7:03pm
James Powell wrote:

Had car radio taken out ,CD player not working ,next morning car would not start ,car dealer then put in new battery and that failed after three days

On March 27, 2014 at 7:41am
Laddie Bolden wrote:

Had a new battery installed in my 1998 Grand Marquis Nov.11, 2013.  Within four months I had to jump-start my car 3 different times.  A NEW battery was installed March 17, 2014. Seven days later my car would not start.  Hence, another jump-start.  I did not drive the car every day, but, after seven days and the battery wouild not start my car?  Thank you.

On April 14, 2014 at 6:32pm
Mindy wrote:

Great article.  Finally an explanation of why my battery has been dying every 2 years: my roundtrip commute is an average of 10 miles per day in city traffic.  Then, when I park, I pop open the trunk for a few minutes while I unload items - thereby, runnng the interior lights.

On May 15, 2014 at 3:46pm
linda davis wrote:

this guy i know i think has put a tracking device on my car and its draining the battery,cause for the last two years every six months..When it goes to every day light savings time, this is when the battery goes…then when i tell him what is going on he will start saying all these stupid things about what could be daring the battery.Then all the sudden he comes up with oh i can’t use my computer it crashed again..i’m waiting for the computer people to come fix it..It sure does happen every time my battery dies… please help me with a possible answer to this mysterious bullshit i have been going through for the last two years….IS MY THINKING POSSIBLE???ABOUT HIM PUTTING THE TRACKING DEVICE ON MY CAR,,,if someone can help me call me….linda 707-455-1591..thanks anyone…

On August 24, 2014 at 9:46am
MUKUL BHARDWAJ wrote:

how much amount of battery comsume when any vehicle starts?

On September 22, 2014 at 11:37am
al periquet wrote:

about batteries, is all business. manufacturers can make them last forever if they want to but the company will shut down in no time.

On October 30, 2014 at 7:19pm
asda wrote:

manufacturers can make them last forever if they want to but the company will shut down in no time.