How To Test A Car Battery (With And Without A Multimeter)

Knowing how to test a car battery is a valuable share of car maintenance that can save you clock time and money down the channel .
But how do you know when you should be testing your battery in the first place ?
In this article, we ’ ll answer that interview and usher you how to test your battery life sentence with and without a barrage tester. then, we ’ ll go over some FAQs to give you a better understand of testing a car battery .

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Let ’ s get started.

How To Test A Car Battery With A Multimeter 

Using a multimeter is one of the most common ways to test your cable car battery .

You can grab one at your local hardware store for less than $ 10 .
Some other car battery examiner tools, like a voltmeter or exponent probe, can besides get the job done. however, a multimeter is your best stake since both a voltmeter and a baron probe are more limited in their capabilities to test battery performance .
The procedure is quite childlike, fair follow these steps :
1. Remove the surface charge from the battery
2. Perform a flying ocular inspection
3. Set up your multimeter
4. Connect the multimeter
5. Check the multimeter ’ second display
6. Turn on your cable car
however, before testing your battery with a multimeter or any other car battery tester, there are a few things to remember .
1. These instructions are for what ’ mho referred to as maintenance-free batteries.
These batteries don’t have fictile caps on each cell. If you have a battery with fictile caps, you will need a hydrometer to test it, not a multimeter .
2. Always wear rubber eraser gloves and goggles when working on your battery. This will protect your skin and eyes from battery acid .
With that taken wish of, let ’ s get into how you can start testing your battery liveliness :

Step 1. Remove The Surface Charge From The Battery

To do this, t urn your headlights on for about two minutes. Don ’ thyroxine turn the car on, precisely the headlights. We do this because we need to test the barrage ’ randomness resting voltage ; otherwise, you can get a assumed learn, as the battery might distillery be holding a charge from the alternator .

Step 2. Perform A Quick Visual Inspection

While you ’ ra waiting with the headlights on, you can go ahead and give the battery a quick ocular inspection. You want to look out for any corrosion buildup which could be affecting your battery performance .
It normally looks like a white or yellow crust that forms around your battery terminals . Corrosion might flush explain why you ’ re having battery issues in the first gear stead .
If you see some corrosion, you can clean that off with a battery-cleaning solution, like baking pop and water or some finely emery paper. Read this template for instructions on safely removing corrosion from your barrage .
While you ’ re there, double-check that you fastened each battery cable correctly .
If everything looks all right, move ahead to the adjacent step .

Step 3. Set Up Your Multimeter 

now that you ’ ve prepared the battery, you can start setting up your digital multimeter to test your battery voltage .
To do this, adjust it to about 20V DC volts . Setting it to 20V isn ’ t a must ; the important thing is that it ’ second above 15V DC volts , so you get the adjust understand. You can go ahead and turn your headlights off .

Step 4. Connect The Multimeter 

Touch the probes on the digital multimeter to the corresponding points on the battery .
first, connect the negative cable television ( black ) on the multimeter to the negative terminal on the battery. then connect the positive point ( bolshevik ) on the multimeter to the convinced end on the battery .

Step 5. Check The Multimeter’s Display

When connected to a in full charged battery, the multimeter will highlight your car battery electric potential as being between 12.5V to 12.6V if everything is working as it should be .
Remember, the outside temperature and your battery type affect your battery electric potential .
For exemplar :

  • For a standard lead acid battery at around 80℉ (27℃), a good battery that’s fully charged will be in the 12.2 – 12.6 volt range. Whereas a fully charged AGM battery will have an open circuit voltage of about 12.8V to 12.9V. 
  • At 30℉ (-1℃), the battery voltage will be around 12.58V and 12.51V. 
  • At 0℉ (-17℃), your volt reading will be slightly less if you have a good battery.

For reference book, a go acidic battery that ’ s about 75 % charged will have a volt read of around 12.45V. Anything below 12V suggests something is wrong with your battery and credibly won ’ deoxythymidine monophosphate start your car .
If the multimeter displays the battery ’ second voltage as anything between 12.3V and 12.5V, it could use a commission. If it doesn ’ deoxythymidine monophosphate depart, you can jump-start your cable car from person else ’ mho with a pair of jumper cables . once your vehicle is running, the alternator can charge your battery. alternatively, a barrage charger suited to your car battery type will besides work .
Anything below 12.2V suggests the battery ’ mho resting electric potential is decrepit, and you ’ ll need a substitute .
Tip: Owning a working set of jumper cables is a must. Of course, knowing how to use them is besides full of life .

Step 6. Turn On Your Car 

Have person else turn the car on while the digital multimeter is placid attached.

The electric potential read should change, but the electric potential dangle shouldn’t go below 10V. If it does, your battery international relations and security network ’ triiodothyronine producing the chastise voltage to power your car .
If you ’ re getting a bombastic electric potential drop, your best bet would be to organize a new battery.
however, if the readings are about 12.6V, you should have a good battery, and something like a bad alternator may be causing the publish .
But what should you do if you don ’ t have a multimeter available ?

How To Test A Car Battery Without A Multimeter

While performing battery testing, although a multimeter is the most efficient method acting, it ’ s not the only method .
If you don ’ t have a digital multimeter or another type of battery tester on bridge player, there are a few things to help figure out how your battery is performing .

1. Perform A Quick Visual Inspection

see the battery international relations and security network ’ triiodothyronine leak and it ’ s not bulging — your battery case should be a perfectly square box. besides, count for corrosion around your battery terminals and ensure that each battery cable is connected securely .
If everything seems fine, go to the following step .

2. Test The Battery

start by turning your car off and switching the headlights on. Leave them on for about 15 minutes .

3. Crank The Engine 

After waiting round 15 minutes with the headlights on, crank the engine and see what happens. You ’ ll probably need some help here so you can keep an eye on each headlight. You might see your headlight dim slenderly as you start your cable car ; this is convention .
however, there are a few things that suggest you have a problem with your charging organization :

  • Your headlight gets much dimmer or turns off entirely 
  • The engine takes a while to turn over
  • There’s a clicking noise 

Remember that this international relations and security network ’ t about angstrom accurate as using a digital multimeter, but you can use it to tell if your battery is performing as it should .
If your car turns on fine and the headlights aren ’ metric ton dim, your charging organization is credibly functioning normally .
Having said all of that, how do you tell if you have a bad barrage ?

4 Signs Of A Bad Battery

generally, you should conduct a car battery electric potential screen about twice a year to avoid sum battery failure. however, there are several other signs to look out for to help prevent a absolutely car battery. If these symptoms appear, don ’ thymine wait for routine car maintenance to get your battery checked :

1. Slow Engine Starting 

This is frequently the first gear sign of battery failure .
When something ’ s ill-timed, your battery will struggle to hold a wide charge, which frequently manifests as a dense locomotive startle .
The main reason for this is the barrage not sending adequate power to the crank motor to get the engine to turn over. If this is a common issue for you, there ’ s a good luck you ’ ll have a dead car barrage reasonably soon .

2. Dim Lights

As mentioned above, dimming lights is another estimable indicator of something incorrect with your battery, though this besides refers to your interior lights .
For exemplar, you may besides notice issues with another electrical component, like the power windows or radio. An electric component like this is more probably to fail wholly, while your lights will start dimming before they fail instantaneously .

3. A Clicking Noise 

If your battery can ’ t send enough might to the appetizer drive to turn your car on, you ’ ll likely hear a series of clicks . This will tell you that you have a dead battery and your car won ’ t start .

4. Battery Light On Your Dash

You may notice a battery indicator light on your splashboard when your battery starts acting up. Some cars will throw up a general confirmation locomotive unaccented, whereas others may show an prototype of a battery .
If that light is on in your daunt and you ’ re noticing a few early symptoms, it ’ s a safe bet you ’ rhenium dealing with battery failure, and you ’ ll credibly need a battery surrogate .
now let ’ s front at some FAQs to give you a better understanding of your car battery .

5 Car Battery FAQs

here are the answers to a few general questions about car batteries :

1. What Is A Multimeter?

A multimeter is a simple barrage examiner used to measure volts ( V ), Amps ( A ), and electric resistance ( Ω ) from an electric source. Most frequently, though, a multimeter is used to test the intensity of car batteries .
Using it to test your car battery will give you an accurate voltage reading. A multimeter can besides indicate how your battery holds up while powering respective electric components .

2. How Long Should My Car Battery Last?

several factors affect your car battery ’ mho life. The first factor is clock — batteries have a finite lifespan. Generally, a raw battery will last between three and five years, but your drive habits and how long the car remains undriven can reduce that .
Some other factors that affect your barrage ’ mho life include :

  • Excessive heat 
  • Cold 
  • Vibrations 
  • The alternator

3. How Do I Know When My Battery Needs To Charge? 

here ’ s a battery voltage road map when your engine is not run :

  • 12.6V or more  — 100% charged
  • 12.4V+ — 75% charged
  • 12.2V to 12.4V — 50%, needs to charge
  • 12.05V — 25%, needs to charge
  • < 12V — Discharged

4. What Is A Load Test, And How Do I Perform One?

A barrage load test is a battery testing serve that involves measuring the amperes produced by a charged battery . Cold cranking amps ( CCA ) is the condition used to describe the barrage ’ second exponent .
Performing a burden test helps determine if your battery can might the starter centrifugal based on the cold crank ampere denounce .
You ’ ll need a battery load examiner to perform a successful load examination.
You can pick up a battery load examiner for about $ 20 .
here ’ s how you use it :

  • Step 1 — Begin by fully charging the battery. You need to do this to ensure you get an accurate result. You can use a battery charger if you have one on hand. Use your multimeter to check if your battery voltage is the same as on the battery label. 
  • Step 2 — Then, make sure your multimeter is ready to measure voltage and connect it to the battery. If the voltage reading is lower than 10% of what’s on the label, you’ll need to charge the battery before doing a load test. 
  • Step 3 — You need to disconnect the multimeter from the battery. 
  • Step 4 — Examine the battery label again, this time looking for its ampere rating. You should notice a “CCA” followed by a number. This number indicates the cold cranking amps. Take that number and halve it to get to the figure for your load test. For example, if your cold cranking amp rating is 500, then 250 is the figure you’ll need. 
  • Step 5 — Connect the sensors of your load tester to the positive and negative battery terminal, making sure to connect the positive to the battery’s positive terminal and the negative to the negative battery terminal. 

Be certain to leave the sensors for at least 15 seconds.
then, read the lode tester and compare it to the number you calculated in step 4 .
If the read is 10 – 15 % less than your account number, your battery can ’ deoxythymidine monophosphate produce the power to run your locomotive .

5. What’s An Easy Solution To My Car Battery Troubles? 

If you find yourself with a defective barrage, you ’ ll need a battery substitute .
fortunately, RepairSmith can help you with all your fomite rectify and car battery care needs .
RepairSmith is a commodious mobile fomite care and haunt solution. here ’ s why you ’ ll want us to handle your barrage issues :

  • Replacements and fixes can be performed  in your driveway
  • Professional technicians perform the vehicle inspection and servicing
  • Online booking is convenient and easy
  • Competitive and upfront pricing
  • We only use high-quality equipment, tools, and replacement parts in repairs 
  • RepairSmith offers a 12-month | 12,000-mile warranty on all repairs

Fill out this shape for an accurate price appraisal of a car battery successor and other repairs .

Final Thoughts

Performing a barrage screen and regular car battery maintenance can help avoid a dead battery down the line.

Remember, as your battery ages, it ’ ll start becoming less efficient, and it ’ s helpful to know what those warning signs are .
And while it ’ s possible to replace a car battery yourself, it can be complicated. If you ’ five hundred prefer to leave it to the professionals, you can always rely on RepairSmith .
just contact us, and our adept mechanics will be at your driveway to take wish of all your cable car battery needs .

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Category : Tutorial

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