Owned and driven an automobile for a few years? If so, you have probably suffered the agony of a bad battery.
Your car’s battery plays a part in getting you off on the right foot for a drive to work, to the store or just a ride in the country. When that battery fails or even starts to weaken, enjoyable trips may never leave your driveway.
So how long does a car battery last? Read on to find out.
Note: In this article we will discuss batteries for conventional gasoline and diesel fueled cars, trucks and SUVs. See this article for batteries for electric and hybrid vehicles.
How Long Do Car Batteries REALLY Last?
Once, when your purchase of the new car included the manufacturer’s very best quality battery, life expectancy could be five years plus. How many miles would we see from it, perhaps 60,000. But not in the majority of new cars today.
To lower the first cost of car, most manufacturers have reverted to putting out a run of the mill battery with every vehicle made. It may even have a label or name on the side. But be assured, it is more than likely the same or similar to one your Trusted Repair Shop would install.
Generally, replacement lead-acid batteries will age and lay down in the interval of 2 to 5 years.
This is where AGM batteries excel and we’ll consult on them below. These types have proven to be more reliable. AGM batteries can last up to 10 years.
The warranty in years on a lead-acid battery will fairly predict when it is going to give up the ghost. AGM-type batteries sold today in general do not carry warranties to match the life expectations put forth by the different manufacturers.
When you purchase a new battery, put the receipt into the glovebox. It is your proof-of-purchase and gives the baseline date for any warranty benefit you might be entitled to.
Car Battery Basics
Let’s take a closer look at the two types of automotive batteries available today. These are the lead-acid and the AGM (absorbed glass mat) battery.
Lead-acid battery
Lead-acid batteries have been around dating back to 1800s. This old technology is still serving us well. Lead-acid batteries have six individual cells, each with a free volume of acidic electrolyte liquid. Each of these cells produces just more than 2.1 volts of electricity.
As a result, a car battery will test at 12.6 volts when fully charged. This type of battery can leak the electrolyte if it is laid on its side or turned upside down.
AGM battery
AGM (absorbed glass mat) batteries were developed quite a number of decades ago and were initially intended for military use.
These batteries also contain six cells, but the electrolyte is “soaked into” glass-fiber mats not allowing the fluid to spill or leak if the battery is tilted upside down.
For consumers, the use of AGM batteries came to motorcycles first and, more recently, to pleasure boats and cars.
Alternator role
No discussion regarding automobile batteries would be complete without a look at the function of your car’s electricity generator, the alternator.
The alternator provides electrical power (direct current or DC) to charge the battery when your engine is running. It also provides the power necessary to run the engine control systems as well as all the electrical accessories in your car.
What Affects a Car Battery’s Lifespan?
Both your driving habits and where you live can impact battery longevity. Your home location, for instance, and where you work may dictate a daily use pattern that can’t be easily changed.
How might the actual driving pattern either shorten or extend the battery’s life? Consider:
#1. Short Daily Trips (20 minutes or less).
This cuts down on battery life. Such trips restrict alternator operation so that it may not fully recharge the battery.
Beyond just the battery, your automobile’s complete mechanical and electrical systems, plus tires, will wear out faster when driving like this.
#2. Frequent Stops (engine running).
Trips that pick up and/or drop off people fit this description. Think of a taxi cab driver’s habits. Starts and stops, engine running, lights on, air-conditioning and sound system blaring. This draws down the battery, and it may not be topped off again next segment of the trip.
If you can, plan to incorporate these little short trips into a run of 5 to 10 miles and go down the freeway regularly. The battery will benefit from getting a good charge. It will be well worth it, with the engine and drive train fully warmed up.
#3. Longer Trips.
Regularly make the drive a long one, and keep to moderate, to greater than highway speeds. These longer trips will enable the battery to charge fully. You are also cleaning out water-based contaminants in the system, lubricating your engine, and this in itself will help increase its life.
#4. Where You Live.
Do you live in a neighborhood or region that requires you to constantly drive over rough or unpaved roads? Mountains and farm country come to mind.
Rugged roads will subject a battery to sharp impacts. The battery can be jarred, all it takes, so that electrical continuity is interrupted. If this happens the battery is finished, instantly.
If your battery is ruined by rough road driving, replace it with an AGM battery.
You’ll be better off in because they are more rugged and will stand rough roads longer. Note also that AGM batteries are something besides lead-acid types.
Clearing roads of ice can jar the battery, and hold down clamps loose, too. Sometimes, a loosely fit hold-down clamp simply falls off. A loose battery can be jarred to pieces under any driving conditions.
Now and then, you should open the hood and verify that the clamps are in place and the battery resting firmly in position. With hands to wrap in paper towels, grasp the battery in preparation for a shake. Take corrective action if it is loose in the battery compartment.
#5. Extended Periods of Non-Use.
Sometimes your car might sit in the garage for one or two months. Even though the car is parked, guess what? Computer systems will still be business as usual, draining the battery but at low power.
Of course if winter is here with sub-freezing temperatures, the battery drain will be accelerated. With two months of this and a restart may not be possible. In addition the dead battery may refuse to accept a charge and it will have to be replaced.
In the winter the dead battery may freeze and crack the case. Acidic electrolyte then seeps on to the metal structure below with all of the potential corrosion damage that might entail.
Storing that way should go with proper use of a good quality low amperage charger (sometimes called a battery maintainer) on that battery, such as the DieHard 71219. NOCO Genius 2 is another excellent, inexpensive model.
How Old Is My Battery?
So glad you asked. Since age is tied to your battery kicking the lifespan, knowing when your battery was built can be useful. There is always a date stamp imprinted on each battery at the factory when it is shipped.
Typically referred to as the date sticker on the battery, most batteries are date-marked as follows:
- The simple and obvious date format (MM/DD/YY) or (MM/YY). Usually stamped on the top of the battery. Example: 05/20 would be May 2020.
- The date code. Stamped on the top of the battery. A four or five-digit alphanumeric code with the date in the first two characters as follows:
- First character: one letter, which is the month. For example: A = January, B = February, etc.
- Second character: one digit, which is the year within the most recent decade. For example: 8 = 2008, 9 = 2009, etc. C7XXX would be March 2017.
Battery Warranty Start Date
Notice that the manufacture date stamped on the car battery is different from the warranty start date. When the person on the street refers to the date sticker on the battery, he/she is actually talking about a label denoting the purchase date of the battery.
Usually a circle for the year and date is punched out when you buy the battery so you can easily see when the warranty began (along with the receipt for purchase).
Most of the time a car battery manufacturer provides a free replacement if the battery fails during a certain time of the warranty period. For example a battery claiming a 48 month warranty may provide a free replacement if the battery fails in the first 24 months.
If it fails in more than 24 months but less than 48 months, you will usually get a prorated credit to help you buy a replacement battery according to how far away from warranty end you are.
It’s pretty much the same way with 60-month, 72-month, or 84-month batteries, except the period for replacement and prorated is likely different.
Does My Battery Need Replacing?
Since some of the same information is in another article (5 Symptoms of a Bad Car Battery) we’ll be brief here. Your car battery may need servicing or replacing if you observe these symptoms:
- Noted the steadily lit battery warning light in your instrument panel.
- Hard/impossible to start the engine.
- Slight ‘rotten egg’ (hydrogen sulfide gas) smell when you open the hood.
- Dimming of headlight brightness in night driving. Other accessories (windshield wipers) run slowly.
- The battery case is swollen.
Most of the above problems (Items 1 through 4) may be from insufficient charging by the alternator. Check this out and rule out a bad alternator before you purchase a new battery.
You can also get your battery condition checked out at no charge with a “load test” at most good auto parts stores such as AutoZone, Napa, O’Reilly, and others. This can assure you of more battery life remaining or tell you that you may have trouble just around the corner. Highly advised that your battery has survived past the warranty period.
Following any hands-on attention you might give your car’s battery, wash your hands well. This will remove any trace of the acidic electrolyte that may be present on an older battery. You could irritate or even burn, hands if you don’t clean them thoroughly.
Can I just have the Battery Recharged?
Very possible. If your battery suddenly goes dead and you can’t start your car, the battery may not have to be replaced. Two questions should determine what you do about recharging it.
First, ask yourself the question, why did my battery go dead? A faulty alternator, a loose alternator drive belt, corroded battery terminals or cables, any of these faults could cause a battery to discharge little by little. Where the fault lies with one of these items, you need to replace the part, not the battery.
If you simply recharge the battery without ascertaining and correcting the cause of the discharge, the battery will soon go dead again.
Second, how old is the battery? Is it older than its warranty period? If so, you will be better off replacing it. In many cases, the battery may need replacing prior to the warranty period expiring.
In these cases, take your battery back to the original place of purchase and they will usually give you a prorated credit on a new battery (depending on how much time remains of the warranty). This works in much the same way as warranties on new car tires.
Can a Dead Battery be Recharged by Your Alternator After a Jump Start?
Not necessarily. Here’s why. If the battery is simply weak, a recharge from the alternator is fine. But if the battery is completely dead, this can materially shorten an alternator’s service life.
With the engine running, the alternator has the ability to charge a moderately discharged battery while at the same time providing power to engine control systems and accessories.
However, it is not designed to bear the high current drain needed to recharge a dead battery and power everything else as well. A totally dead battery should only be recharged using a quality battery charger such as the Schumacher SC1280 or Tower Top.
How to Test Whether a Battery Charger is Needed
You can quickly determine whether your battery is safe for recharging with your cars alternator with this quick test. Before jump-starting the engine, and with the ignition turned off, check the voltage across the battery terminals with a DC multimeter like this one or one from a local auto parts store.
- If the voltage you read is 12 volts or above you can safely recharge with your alternator.
- If the voltage is below 12 volts, a conventional battery charger will be required.
Situation conditions may affect your decision on this as well. Ex: If you are marooned in the desert wilderness and cannot start your car, getting a jump that restarts it and then driving to a repair facility may be your only option.
In that case, the inevitable recharge by alternator that will happen may, indeed, be your only choice.