Battery Testing Basics – A Few Tips Can Get You a Long Way. Are battery testers accurate

Battery Testing Basics – A Few Tips Can Get You a Long Way

Batteries are a wear item. That’s a fact. Whether you purchase a budget battery or the most advanced AGM battery, at some point it will fail. Whether you live in Phoenix and experience extreme heat much of the year, Grand Forks, SD and experience extreme cold, or in San Diego and have weather most of us would trade for in a minute, your battery is going to die (hint: it will last longer, all things being equal, in San Diego). This makes battery testing critical for vehicular happiness, whether you are a vehicle owner hoping to avoid a future No Start situation or a shop trying to provide the best possible service to your customers.

Battery testing doesn’t have to be overly complicated or difficult, especially if you keep in mind a handful of guiding principles that will allow you to get the most accurate and predictive result. Batteries are relatively predictable and (usually) behave according to a pattern tied to their lifecycle. That said, there are always twists and turns if you test enough batteries in enough vehicles. So, as is true for almost any aspect of vehicle repair and maintenance, deploying a repeatable, logical diagnostic strategy is critical. Below, we’ll suggest a few components of such a strategy.

The Connection is Critical

A theme you will hear expressed a lot in this article is that accuracy comes from making good decisions and putting in the effort, and nowhere is that more true than when it comes to making a good connection. This has many implications, but is most obvious when testing a battery installed in a vehicle. Sometimes, the battery posts are easily accessible despite the vehicle connections, but often they are not. If the battery’s terminals are obstructed by harnesses and other connectors, it is worth the effort (and hassle) to remove those connections to provide proper access to the battery terminals. This can make a huge difference in the results you receive, since those harnesses can (and often do) add resistance, which your tester sees as inside the battery. If you must test through the harness or other hardware, make sure it is tightened properly on the battery posts and that there are no signs of battery corrosion or rust in the connection – this is not ideal, but much better than testing through loose or corroded connections.

In addition, it is important to review the battery design and factor for that specific design when planning your testing regimen. A great example is a battery designed with a terminal composed of a lead base with a steel threaded stud protruding above ( see photo ). This one can be tricky. You’d think, connect to that threaded stud and you’re good to go. Not so fast. Connecting to the lead base (which isn’t always easy) yields a much more accurate read on the battery’s condition. This sort of makes sense – harnesses and other connectors are typically flat and secured/smashed against that lead base, so the connection isn’t really with the stud but with the base.

State of Charge Matters

A battery’s State of Charge (SoC) can and will impact your testing regimen and results. First, there’s surface charge. Surface charge, if we get down to the chemical definition can be relatively complicated, but in this case, we are referring to excess voltage typically found in a recently charged battery. If you attempt to test a recently charged battery, you might find that its open circuit voltage (OCV) is 13.05V or 13.12V or higher. Since your lead acid battery is fully charged at 12.6V or 12.8V, depending on its construction, the excess voltage represents surface charge.

But, surface charge can cause issues in the testing process, depending on the testing method used. If using an invasive load tester, surface charge is not a big concern, because the testing process will pull down that surface charge almost immediately. If using an electronic tester, it is best to relieve the battery’s surface charge by adding a load to the battery, such as turning on the high beams for 15 seconds. This will stabilize the battery, allowing you to get a more accurate assessment of battery health and reduce the likelihood of a “charge and retest” result.

What about low SoC batteries, do they also need special handling? Again, it’s a yes and no, but this time in the opposite direction. For invasive load testing to be accurate, the tested battery needs to be at or above 85% SoC when tested. If it is below this level, which is likely, considering that problem batteries are what get tested the most, it must be charged prior to testing. This takes time, potentially slowing down the diagnosis and eventual repair, but it is absolutely necessary to achieve an accurate result. One of the great benefits of digital testing is that you can accurately test a discharged battery. Of course, there are limits to this. For instance, even though our BA327 can read batteries down to 1.5V, we’d suggest charging a 12V battery prior to testing if it is below 7-8V.

Testing Batteries Over Time

In a recent Product Spotlight, we focused on the value of battery testing when it comes to predictive maintenance. As we noted, all batteries have a certain level of internal resistance, since their internal components are not perfect conductors of electricity. For instance, a battery’s electrodes and electrolyte are not 100% conductive. So, each new battery starts out with a natural level of internal resistance. This resistance will increase as a battery ages, due to the natural chemical process that takes place within all lead acid batteries.

Monitoring and tracking the internal resistance of a battery can be very useful in assessing where that battery is in its lifecycle. Granted, this usefulness only applies to vehicles and batteries that you will see repeatedly over time. So, for service operations that might see a vehicle for service one time or only sporadically, this aspect of battery assessment is not helpful. But, for captive fleets and other service operations, as well as vehicle owners, using battery internal resistance as a predictive tool can be very beneficial. It can essentially eliminate equipment downtime before it strikes, which has tremendous value for fleets and other captive service environments.

Testing Every Vehicle Boosts Revenues

If you are running a shop, the battery tester can be one of your most valuable tools, with a massive return on investment. The trick is, you have to use it to get that return. First, using your tester on every vehicle that enters your service bays improves customer satisfaction. You are able to advise customers about the state of their electrical system and warn them if they have a potential problem. It is just one more way for you and your team to earn the role of trusted advisor. Second, using your tester drives revenue. There are many vehicles rolling around with batteries that are approaching end of life. In addition, many vehicles have problems with a rotating electrical component, such as a faulty starter. Finally, your tester can help to identify problems with belts and battery cables. These items potentially add revenue to each service ticket while helping your customers – win/win! But, these items and issues might go undetected if you aren’t using a quality battery testing tool consistently on every vehicle that enters your shop.

What Testing Method is Most Effective?

This is really a trick question, since there is no “best” testing method. Ultimately, the best testing method is the one that a.) you are most comfortable with, b.) best meets your workflow and c.) you are going to use. There are essentially two approaches, without getting into more complex methods, such as using a scope, etc. The two main camps are digital testing and invasive load testing. There are pros and cons to both methods, which are worth exploring as you develop your testing regimen.

Electronic/digital testing usually involves a variant of passing a signal through the tested battery and reading the response of that signal (more on our approach below). This method has many benefits, one of the most significant of which is that you can use this method to accurately test a discharged battery. Another benefit is that it has the ability to dial its testing process in to match the battery type being tested, assuming that you are using a quality testing solution. This means that an AGM flat plate (traditionally shaped) battery can be tested/judged differently than an AGM Spiral Wound battery – side note: when going the digital route, it should be, and if your digital tester doesn’t distinguish between these battery types, you should be concerned. Another benefit is that digital testing opens the door to a much more detailed analysis of system performance than can be achieved by an invasive tester. When performing a starting system test, for example, you get a specific level that the system voltage dropped to versus watching a needle deflection in the blink of an eye. So, you get 10.2V rather than seeing the needle dip to about 10V. Often, that level of detail is important and useful. Of course, you can get that with your DIMM, but now, you’re grabbing two tools.

Invasive testing involves placing a fixed or variable load on the battery for a specific period of time and monitoring the battery’s reaction to that load, as in, “Can it hold the load or not?” Although this is a more simplistic approach, it is also fundamentally reliable. Proponents of this approach will say that’s all that matters – either the battery holds the load or it doesn’t. For most professional applications, a carbon pile (variable load) tester is the most appropriate choice since it allows the operator to dial the load in accordingly to the battery’s rating. The Battery Council International Standard is 50% of the battery’s rated CCA, so for a 600 CCA rated battery, you would load it to 300A for 15 seconds and follow the assessment provided by the tester. Is the needle holding steady in the green? Battery is good. Is the needle dropping or steady in the red? Battery is bad. Simple and straightforward.

So, where does this leave us? Well, if you’re a vehicle owner with a variety of vehicles and other toys in your stable, we’d recommend a small, quality digital tester, such as our SOLAR BA9. It is quick, accurate, easy to use and versatile. If you’re a pro… well, there are many options, but most advanced diagnostic technicians and leading shops would suggest using both methods. The reality is that there’s always that one weird battery that can fool either method. There’s also the fact that newer battery types, such as AGM and Spiral Wound batteries, don’t die on a straight line, like traditional flooded batteries do. If you’ve had a driver’s license for decades, when you learned to drive, you learned to recognize the sound of a battery reaching end of life. The starting event got dragged out and sounded awful and you knew it was time to head to Sears or your local repair shop to address your obviously weak battery. That’s not how it typically works with AGM, Spiral Wound and other newer battery types. Now, a typical customer complaint is, “On Tuesday, it was cold and the car started right up, but on Thursday, the car won’t start at all.” So, many technicians suggest testing using both methods if there’s any reason to suspect the battery is a problem, using both a digital option and a carbon pile tester.

A Complete Solution for Battery Analysis

The great news for technicians and home wrenchers is that the battery analysis offering from SOLAR provides great options for both testing methodologies. All items are designed for everyday continuous professional use and are built to our exacting standards.

Our BA Series line of Digital Battery and System Testers provides accurate battery analysis in easy-to-use packages with convenient features for efficient and hassle-free use. Our top selling professional testing tool is our BA327 Digital Battery and System Tester with Integrated Printer. It offers comprehensive testing of 6 and 12 Volt batteries and 12 and 24 Volt systems. It has an operating range from 1.5-30V and testing capacity from 40-2000 CCA. It can test many different lead acid battery types, including Flooded, AGM, Spiral Wound, Gel Cell, Start-Stop AGM and Enhanced Flooded batteries. It walks the operator through the testing process, enabling anyone in the shop to achieve an accurate, reliable battery and system assessment. It features 10’ cable reach, multilingual operation, the ability to test against numerous battery rating systems and a counter that enables shops to track the number of tests performed in any given time period.

  • 6/12 Volt battery testing
  • 1.5 to 30V operating range
  • 40 to 2000 CCA testing capacity
  • Temperature compensation
  • Integrated printer

Our SOLAR invasive tester offering also provides reliable and lasting performance for busy shops, fleets and dealerships. Our 1876 1000A Carbon Pile Tester provides variable load testing and can test batteries to 2000 CCA. It features an adjustable scale for 6/12/24V assessment, 54” cable leads to allow easy connections, and heavy-gauge clamps for efficient transfer of the load to the tested battery. It’s a beast and much loved by customers.

We hope this review of battery testing best practices proves helpful to you. For many, it is just a question of familiarity. The more you use your testing tools, the more comfortable you’ll become with them. If you are an enthusiast, your battery tester can really make your life easier. We all have more and more batteries in our life. A quality tester can help you get your arms around your battery investment. If you’re a professional, the tester can really become one of your most valued tools. It can be used to drive customer satisfaction while at the same time growing revenue. That’s an unbeatable combination.

  • Variable load capability to 1000 Amps
  • Tests batteries to 2000CCA
  • 56″ cable reach
  • Large, easy-to-read gauges
  • 1 Year Limited Warranty

What is your approach to battery and system testing? Are you committed to one methodology or do you deploy both methods? Have you ever had a battery-related diagnostic nightmare? We’d love to hear about it in the Комментарии и мнения владельцев below.

6 Responses

How do either of the testing methodoligies work on the AGM batrery when there seems to be no sign of degrading untill it’s too late

The 2 methods are very basic and each has an advantage and or disadvantage. The 2 methods are digital/conductance, and Load testing. Conductance testing was designed to allow testing of cell degradation by passing a signal into 1 post and recording its travel through the battery and back out the other post. Knowing the degradation characteristics of the materials, this is actually a very accurate way to measure the aging and decline of the cell health of a battery. It works! (It was designed to test remote mounted batteries in inclement temperatures where techs would be at risk if they had to charge and discharge and load test for minutes or hours). Since you are passing a signal through the cells, and you are measuring the degradation of that signal (using an algorithm that adjusts for temperature, voltage level, stated capacity, materials etc) the testing can compensate and still be very useful down too extremely low voltages. This can save time! (Which is the main reason it was developed). Especially on an AGM or GEL battery where the charging could take hours before you could run a load test only to find out the battery is junk anyway. A conductance tester can tell you SHORTED CELL or LOW CAPACITY even on a mostly discharged battery and you can then not waste the time to charge it and replace it immediately! Sounds awesome right. However, cell integrity is not the only thing that makes a battery good, and definitely not the only thing that makes a battery fail. imagine a chain on a bicycle. It spins the wheels when pedaled and makes the force of pedal press apply rotation and you have a tool measuring wheel speed to tell you the chain did its job. Now take a hacksaw and saw through 1 of the links 90%. If that bike is upside down on a worktable, there is no weight or pressure of resistance on the wheels which arent in contact with the ground. That 90% damaged chain will pass the RPM test forever because there is no LOAD so the chain will not break that last 10%. Every time you check the RPM sensor, it says the rear wheel is spinning when you turn the pedals, so the chain did its job and is therefore GOOD. Flip that bike over and place a 150-lb rider on the seat and the chain will snap as son as he tries to pedal. The RPM test could not measure that, see it coming, or warn you. Its the wrong test for that type of failure. Load testing solves that issue. In battery testing, load testing is demanding electrical current from the battery cells, either using load devices in the connected circuits (Headlight high beams and blower fans) or applying an external load (Carbon pile testing). Now you arent measuring electronic signal integrity passing through the cells. You are real-world testing the battery the way it will be used! Power was put in by charging the battery, so how stable does it deliver that power and how stable does its charge rate remain after a fixed amount of delivery? Lets get it out of the way and say it once and for all: LOAD TESTING IS A SUPERIOR TEST IN EVERY WAY BUT CONVENIENCE. It measures the battery in ways conductance cannot. You could have a battery that has good cells and they are all fully charged and the conductance tester will accurately say “800CCA available, Charge rate 100%, GOOD BATTERY”. Then install it and for a moment its all good, then you go to crank it and there is a CLICK and the power drops from 12v down to say 5v or 3v, battery goes from full charge to suddenly seeming DEAD. Huh? But my Hi tech digital tester just measured it at 12.6v and 800cca. The tester probably isnt wrong. The CELLS have that voltage and potential in them. But conductance is simply a voltage level check and a signal degradation measurement. Now we are back to the bicycle chain analogy. If the internal connection of those fully charged perfect condition cells is resisted then what good are they? They have 12v and 800cca in them but you cant get to it and use it! Say the car had loose battery cables. This causes high resistance in the current flow and resistance in electricity equals HEAT! The battery post temperatures rose every time the vehicle was driven to very warm or hot levels far above normal. the connection of the battery posts to the cells inside the battery gets very hot and degrades or even breaks entirely. So now you have 12.6v and 800ccs in those tested cells, with 2 battery posts that are not able to pass the current of 200amp that the starter will draw. You Conductance test told the truth, but it had no way to see that the battery post connection was 80% severed because the signal it sends is unloaded. Its merely passed through to see how it changes in the cells, and then was easily able to pass the bad connection because there is no resistance if there is no demand. So why test with Conductance at all? I just showed that you cant trust it. That isnt entirely true. When a conductance tester tells you it sees a shorted cell, it has identified a flaw in 10 seconds that may take 3 or 4 hours with a load tester on a discharged AGM or GEL. It saves time and flags broken and bad batteries quickly and easily usually without any recharge before testing. Its not perfect. The lower the charge in the battery the higher the chance of a conductance test saying FAIL even on a battery that may be good after charging, or giving a CHARGE AND RETEST message that will ultimately fail after charging (a battery rated at 800cca tested at 8v says charge and retest, you charge it to 12.5v and then it shows max capacity of 450cca, so it was bad already why did it ask for a charge and waste 4 hours. ) Conductance testing can quickly and easily identify Internal Shorts, Bad battery cells and LOW CAPACITY of cells. Any of these problems means replace that battery and waste no further time on it! But it cannot identify resistance issues, temperature variation issues, post connectivity issues, or the load and recovery rate of the battery. All that is done using a fully charged load test. Which will also tell you in a roundabout way if you have any shorted or low capacity cells. The battery must be fully charged to run the test accurately, and if any cells are weak or shorted, or the posts have bad connectivity internally, the battery will fail the load test. (Usually 50% of rating applied for 10 seconds). It cant fake it or lie, there are no algorithms computed against theoretical values and measuring how many 200lb bench presses an athlete can do to determine if he will be a good defensive end and lead his team to a superbowl. Did the battery stay above 10v while the load was applied, and did it recover back to near full voltage after? Cut and dried. If it can do that on a load test, it will start your car! Drawbacks of course. Load testers get HOT so they do fail and have to be repaired/replaced. Also load testing a battery is abusive and can damage it if done too long or too often. And of course the biggest reason conductance has been so popular the past 20 years: convenience. A load test requires a carbon pile, and that the battery be 90% charged or more. a conductance test you can just walk up, run it and give an answer in 60 seconds! The screens prompt you with instructions, and then make printouts for you! Conductance is fast, easy, and finds enough of the problems that many techs use it because of the time savings. The testers are small, easily mobile, and the printouts are impressive to customers. If you want to find some problems and are OK with occasionally missing a few. but being finished quickly on every car, conductance is a good choice. It works enough of the time that you usually stay ahead of the curve. But if you want accuracy, if you wanna be right, the load test is the superior choice in every other way that matters. And before you ask, there have been only a few testers that combined the 2 (Whats the point? if you are gonna do load then you dont gain much from conductance except perhaps capacity measurement and fail predictability based on degradation algorithms?). The problem with those testers is and has been the load testers break with repeat use. Its what they do. And when that happens, the other half, becomes useless as well as the algorithms are adjusted to factor in load and it wont measure accurately without it. The units broke much much more often than conductance only units and were usually expensive. So buy 1 of each if you want both styles of test.

Kelly – Thanks for your very thorough reply to Robert. The only clarifying detail we would add is that our BA Series Digital Battery and System Tester offering adds microload technology to our signal sending process. While only a fraction of the load created by a carbon pile tester, it does provide many benefits in the testing process. It reduces surface charge on a recently charged battery, it stabilizes the battery’s state of charge, it does provide enough load to sense some problems noted by Kelly and it reduces the number of “Charge and Retest” results. All of these are good things and result in a more successful and predictive (accurate) assessment of battery health. Thanks, Jim from Clore Automotive

Thank you for your detailed explanation on testing batteries. I found this article very helpful to me, an Automotive Tech for 49 years now and still at it. We as techs get very used to working day to day on common issues like you have just explained, that we take things for granted. When we read articles like the above you have just explained, it does one very important thing. It reinforces our practices to just remind ourselves how to conduct our repairs in the appropriate manner and feed guidance and knowledge helping us improve our services. Tell me and i will forget, show me and I will remember. Cheers Oliver M

My car is at the dealer now because of no start issue. Dealer said my battery failed all the tests and was replaced with a new battery. The car still won’t start. 2019 GNC Terrain SLT. I’m thinking they are just throwing parts at it and creating a large bill for me. The towing company tested the battery at 11.5v

Tom – Thanks for adding to the discussion. It sure can be frustrating when the electrical system starts going sideways. Keep pushing for them to get to the root cause. 11.5V is low and there could be many causes for that. We wish you all the best. Thanks again, Jim from Clore Automotive

Fluke 500 Series Battery Analyzers increase accuracy and safety, reduce testing time

To help ensure reliability, stationary batteries need to be maintained and tested regularly. Even maintenance free batteries require regular testing because they can deteriorate over time. All it takes is one battery in the string to fail to take the entire string off-line. One bad battery will affect the usable life of adjacent batteries by raising their charge voltage. Worse still, a battery or interconnect with a high impedance could overheat, ignite, or explode during a discharge.

In addition to providing backup power, stationary batteries are increasingly used to store renewable energy, such as solar and wind. Those batteries are subject to the same potential degradation and need to be tested regularly.

Closing the feature gap in battery testers

While battery testers have been around for quite a while, a few years ago Fluke began to notice a growing gap between what was available and what was needed to effectively test stationary battery systems. Most of the battery testers out there had either no CAT rating or a low CAT rating, says Chris Gloger, Digital Multimeter Business Unit Manager for Fluke. We wanted to develop a battery analyzer that was not only more efficient but also had a CAT III rating to provide more safety.

Fluke had the advantage of being able to develop their battery analyzers from the ground up to address the requirements of the IEEE Standard 1188, which was established in 2005 after most other battery analyzers on the market had been developed. This standard governs maintenance, test schedules, and testing procedures for optimizing the life and performance of stationary batteries. We started with the IEEE standard and asked ourselves ‘How do we make those tests safer and how do we make them quicker for customers?’, says Gloger.

The answers to those questions led to the development of Fluke 500 Series Battery Analyzers. These intuitive test tools were specifically designed for measuring all kinds of stationary batteries including GEL, AGM (absorbed glass MAT), lithium-ion, and wet-cell lead-acid.

The 500 Series analyzers offer improved impedance test performance even in high-ripple environments. What’s more, their intuitive user interface and intelligent test probes simplify the testing process by guiding technicians quickly through setups. The result is reduced measurement complexity and cost, and increased accuracy, safety, and operational efficiency.

Multiple tests at the same time

All three Fluke 500 Series Battery Analyzers—the BT 510/520/521—offer a broad range of battery test functions including simultaneously measuring DC voltage while testing internal resistance, and full condition testing using automated string function testing.

The Fluke BT520 and BT521 include an Intelligent Test Probe with an integrated LCD display that shows measurements right on the probe. You can capture measurements automatically in sequence mode or manually by pressing the save button on the probe. The LCD display indicates that the measurement has been taken and saved and uses audible voice cues to indicate which measurements in the sequence have been made. The voice count battery ID identifies which battery you’re testing to help you keep track of your progress. That’s especially handy when testing a long string of batteries.

The BTL21 Intelligent Probe on the BT521 analyzer adds an infrared temperature sensor so you can measure temperature and up to two other data points simultaneously—1000VDC, 600VAC, and ripple— to provide a more complete view of battery health.

  • Ergonomic two-prong test lead probes with a kelvin connection to ensure resistance measurement accuracy
  • Replaceable tips to extend test lead life and further reduce the cost of ownership
  • Long reach test probe extenders for testing double stacked battery cells

Easy analysis and reporting

When you’ve finished testing, just plug the battery analyzer into your PC via the USB port and quickly export measurements using Fluke Battery Management Software. From there you can easily compare results, analyze trends, and generate battery analysis reports.

In addition to simplifying testing, the Fluke Series 500 analyzers offer several ergonomic features for easy handling. Their compact design and rugged construction make it easy to take them just about anywhere. The Smart lithium-ion battery delivers more than eight hours of continuous operation. And you can quickly see the battery charge status through the built-in LEDs. Plus, each unit comes with a shoulder strap, belt strap, and magnetic hanger to provide hands-free operation.

Whether you’re responsible for maintenance, troubleshooting, or performance testing on individual stationary batteries or battery banks, you can work faster, safer, and more accurately with Fluke 500 Series Battery Analyzers.

How Battery Testers Work. A Guide

Most batteries do not come with in-built meters to notify when they are out of power. This is where battery testers come in handy.

Batteries play a major role in everyday life. From mundane devices to electricity in telecommunications, public transportation and medical procedures. Simply put, they are a key part of the energy transition.

So we use battery testers to measure them. But how do these devices work, and how to use one? Keep reading!

What Is a Battery Tester?

Battery testers are designed to test the remaining capacity of a battery’s charge. They work by applying a load and monitoring the voltage response of the battery.

With this, the tester can identify how much power is left. If a battery has a charge, the ink heats up as the current passes through it.

A higher temperature indicates the battery has more current. The gauge from the battery tester usually changes colour based on the temperature.

Current vs charge. The current is the rate of flow of charge, whereas the charge is the physical property of matter. In batteries, the current is what actually charges the battery.

Further, battery testers are ideal for monitoring and troubleshooting. They are, in fact, used across a range of applications and industries, such as:

  • Automotive
  • DIY and domestic purposes
  • Electrical
  • Facility maintenance
  • Industrial maintenance
  • Test and measurement

Convenient to use, these devices provide quick results, making them a must-have tool. Whether you are a DIY enthusiast or professional, a battery tester always comes in handy.

How Does It Work?

As the name suggests, the testers work by testing the current that comes from a battery. Most basic battery testers use conductive ink that responds to minute temperature changes.

When contact is made with both positive and negative contacts on the battery, the current is released. This conductive medium measures the battery charge (amperage). Each tester comes with a gauge that reflects the level of the charge.

Take note, though, that these testers only measure current. On batteries like lithium, the reading results tend to be inaccurate. This is because the current does not wear down evenly. It takes a significant drop at certain charge levels.

over, the batteries will read fully charged even if they only have a half remaining. To test a lithium battery, you need to use a battery conditioner or a tester designed for rechargeable batteries.

As battery testers solely measure current, they provide more accurate readings.

Note: The red one is positive. the black one is negative (-). Never connect the red cable to the negative battery terminal or a vehicle with a dead battery. Otherwise, this will cause a full or dead short circuit.

Different Types of Battery Testers

There are different types of battery testers, each suited to varying battery types and sizes.

Electronic battery tester

The electronic and digital types are the most common ones used for testing the remaining capacity of a battery. Most digital models feature an LCD, showing the result in a clear and easy to read format.

Depending on the model, the result is displayed in the form of bars or a graph. This enables quick reading and analysis of the test results.

Domestic battery tester

Also known as the household battery tester, this type is usually used for testing cylindrical batteries. This includes double and triple A batteries and 9V PP3 batteries.

A domestic battery tester covers the majority of everyday household batteries. It is also suitable for testing a combination of battery types, such as C and D batteries.

These battery testers units are a great example — and are worthy of investment if you are looking for one!

All in One Battery Tester – AAA/AA/C/D/Lithium Button Cells – No longer available

The All-In-One Battery Tester can test the battery strength of more than 12 types of batteries. Suitable for standard AA/AAA/C/D/9V batteries, button cells, and lithium batteries, e.g. in digital cameras.

Features an easy-to-read LCD indicating the battery level capacity.

Mini Battery Checker AA, AAA, C, D, 9V Coin Cells

An inexpensive, compact and convenient battery testing solution. This unit accommodates AAA, AA, C, D and 9V battery sizes and makes testing your batteries a snap.

Universal battery tester

Universal battery testers are suitable for batteries in a range of different sizes. Similarly to domestic battery testers, they are primarily used for cylindrical batteries.

Universal Battery Tester

This lightweight, easy to carry Universal Battery Tester is a simple yet effective model. It works with standard and rechargeable household batteries, including Lithium-based batteries.

With this unit, you can test voltage, capacity, and internal resistance. Plus, it also works with alkaline and various other non-rechargeable batteries.

Car battery tester

Car battery testers are intended for use with lead-acid batteries. These testers connect to vehicle batteries to provide a clear sign of the following:

Battery testers for automotive applications are important. It is crucial as high currents are drawn during start-up. Ensure that your tester is compatible with lead-acid batteries before use for safe testing conditions.

Have a look at this 12VDC lead-acid battery tester for vehicles below!

12VDC Lead Acid Battery Tester including SLA, AGM, GEL – No longer available

This battery tester works on all automotive 12V lead-acid batteries. Suitable for testing various battery types, including:

  • Ordinary lead-acid battery
  • AGM flat plate battery
  • AGM spiral battery
  • GEL battery

It can quickly and accurately measure the alternator’s charging and starter’s cranking conditions. Plus, it can identify batteries with bad cells.

With reverse polarity protection design and meets major battery testing standards such as:

Additionally, this battery tester features an LCD display to indicate the results. It has a menu tab and clips to connect the battery tester to the vehicle’s battery.

How to Use Battery Testers

Each model comes with an instruction manual or manufacturer’s guidelines. We recommend always referring to it before getting started.

Additionally, ensure the tester is fully functioning and compatible with the type of battery you own. After these few pointers, the actual process is relatively simple, with only two steps.

First, insert the battery into the tester. Make sure the positive and negative contacts on both the battery and device match up. Next, secure the battery firmly in place, then take the reading.

After use, store the device in cool, dry conditions such as within your toolbox. This helps maintain and prolongs its lifespan while minimising the risk of damage.

Tip: Do not use a wet cloth when cleaning as this could damage the battery tester. Instead, use a clean cloth or specialised electronics cleaning wipes.

How To Take a Meter Reading?

Once the battery is correctly positioned, you should be able to take a voltage meter reading. Depending on the model you have, the output may vary between different result formats.

If your tester displays a graph or chart, it should be easy to assess the battery’s remaining capacity. But as a general rule, batteries in the green or pointing towards the higher end of the scale are in good working order.

In contrast, batteries with results around the middle of the scale may still be usable for use in sole lower-power applications. Even so, close monitoring will be required.

At last, batteries in the red section or lower end of the scale need to be changed or recharged. They are most likely to have little remaining capacity.

The Bottom Line

The easiest way to check a battery is to use a dedicated battery tester. Suppose you are checking your vehicle battery, use a unit made for automotive testing.

And when purchasing a unit, you must ensure that the tester is compatible with the batteries you have. Additional features will also largely come down to personal preference and requirements.

Some key factors to keep in mind when looking for the best battery tester include:

As for car battery testers, the unit must be dependable and reliable.

In a nutshell, a battery tester will help you determine if your battery (or car’s) is nearing the end of its usefulness and whether you need to replace it or not.

© Wiltronics Research Pty Ltd 2022

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

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Knowing how to test a car battery is a valuable part of car maintenance that can save you time and money down the line.

In this article, we’ll answer that question and show you how to test your battery life with and without a battery tester. Then, we’ll go over some FAQs to give you a better understanding of testing a car battery.

How To Test A Car Battery With A Multimeter

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

You can grab one at your local hardware store for less than 10.

Some other car battery tester tools, like a voltmeter or power probe, can also get the job done. However, a multimeter is your best bet since both a voltmeter and a power probe are more limited in their capabilities to test battery performance.

The process is quite simple, just follow these steps:

However, before testing your battery with a multimeter or any other car battery tester, there are a few things to remember.

These instructions are for what’s referred to as maintenance-free batteries. These batteries don’t have plastic caps on each cell. If you have a battery with plastic caps, you will need a hydrometer to test it, not a multimeter.

Always wear rubber gloves and goggles when working on your battery. This will protect your skin and eyes from battery acid.

With that taken care of, let’s get into how you can start testing your battery life:

Step 1. Remove The Surface Charge From The Battery

To do this, turn your headlights on for about two minutes. Don’t turn the car on, just the headlights. We do this because we need to test the battery’s resting voltage; otherwise, you can get a false reading, as the battery might still be holding a charge from the alternator.

Step 2. Perform A Quick Visual Inspection

While you’re waiting with the headlights on, you can go ahead and give the battery a quick visual inspection. You want to look out for any corrosion buildup which could be affecting your battery performance.

It usually looks like a white or yellow crust that forms around your battery terminals. Corrosion might even explain why you’re having battery issues in the first place.

If you see some corrosion, you can clean that off with a battery-cleaning solution, like baking soda and water or some fine sandpaper. Read this guide for instructions on safely removing corrosion from your battery.

While you’re there, double-check that you fastened each battery cable correctly.

If everything looks alright, move ahead to the next 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 batterys 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’s above 15V DC volts, so you get the correct reading. You can go ahead and turn your headlights off.

Step 4. Connect The Multimeter

First, connect the negative cable (black) on the multimeter to the negative terminal on the battery. Then connect the positive point (red) on the multimeter to the positive terminal on the battery.

Step 5. Check The Multimeter’s Display

When connected to a fully charged battery, the multimeter will highlight your car battery voltage 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 batterys voltage.

  • 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, a lead acid battery that’s about 75% charged will have a volt reading of around 12.45V. Anything below 12V suggests something is wrong with your battery and probably won’t start your car.

If the multimeter displays the battery’s voltage as anything between 12.3V and 12.5V, it could use a charge. If it doesn’t start, you can jump-start your car from someone else’s with a pair of jumper cables. Once your vehicle is running, the alternator can charge your battery. Alternatively, a battery charger suited to your car battery type will also work.

Anything below 12.2V suggests the battery’s resting voltage is weak, and you’ll need a replacement.

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Tip: Owning a working set of jumper cables is a must. Of course, knowing how to use them is also vital.

Step 6. Turn On Your Car

Have someone else turn the car on while the digital multimeter is still attached.

The voltage reading should change, but the voltage drop shouldn’t go below 10V. If it does, your battery isn’t producing the correct voltage to power your car.

If you’re getting a large voltage drop, your best bet would be to organize a new battery.However, if the readings are around 12.6V, you should have a good battery, and something like a bad alternator may be causing the issue.

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, it’s not the only method.

If you don’t have a digital multimeter or another type of battery tester on hand, there are a few things to help figure out how your battery is performing.

Perform A Quick Visual Inspection

Ensure the battery isn’t leaking and it’s not bulging — your battery case should be a perfectly square box. Also, look for corrosion around your battery terminals and ensure that each battery cable is connected securely.

If everything seems fine, move to the next step.

Test The Battery

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

Crank The Engine

After waiting around 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 slightly as you start your car; this is normal.

However, there are a few things that suggest you have a problem with your charging system:

  • 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 isn’t nearly as 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’t dimming, your charging system is probably functioning normally.

Having said all of that, how do you tell if you have a bad battery?

Signs Of A Bad Battery

Generally, you should conduct a car battery voltage test about twice a year to avoid total battery failure. However, there are several other signs to look out for to help prevent a dead car battery. If these symptoms appear, don’t wait for routine car maintenance to get your battery checked:

Slow Engine Starting

This is often the first sign of battery failure.

When something’s wrong, your battery will struggle to hold a full charge, which often manifests as a slow engine start.

The main reason for this is the battery not sending enough power to the starter motor to get the engine to turn over. If this is a common issue for you, there’s a good chance you’ll have a dead car battery fairly soon.

Dim Lights

As mentioned above, dimming lights is another good indicator of something wrong with your battery, though this also refers to your interior lights.

For example, you may also notice issues with another electrical component, like the power Windows or radio. An electrical component like this is more likely to fail altogether, while your lights will start dimming before they fail outright.

A Clicking Noise

If your battery can’t send enough power to the starter motor 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.

Battery Light On Your Dash

You may notice a battery indicator light on your dashboard when your battery starts acting up. Some cars will throw up a general check engine light, whereas others may show an image of a battery.

If that light is on in your dash and you’re noticing a few other symptoms, it’s a safe bet you’re dealing with battery failure, and you’ll probably need a battery replacement.

Now let’s look at some FAQs to give you a better understanding of your car battery.

Car Battery FAQs

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

What Is A Multimeter?

A multimeter is a simple battery tester used to measure volts (V), Amps (A), and resistance (Ω) from an electrical source. Most often, though, a multimeter is used to test the strength of car batteries.

Using it to test your car battery will give you an accurate voltage reading. A multimeter can also indicate how your battery holds up while powering several electrical components.

How Long Should My Car Battery Last?

Several factors affect your car battery’s lifespan. The first factor is time — batteries have a finite lifespan. Generally, a new battery will last between three and five years, but your driving habits and how long the car remains undriven can reduce that.

Some other factors that affect your battery’s lifespan include:

How Do I Know When My Battery Needs To Charge?

Here’s a battery voltage guideline when your engine is not running:

  • 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

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

A battery load test is a battery testing process that involves measuring the amperes produced by a charged battery. Cold cranking amps (CCA) is the term used to describe the battery’s power.

Performing a load test helps determine if your battery can power the starter motor based on the cold cranking amp rating.

You’ll need a battery load tester to perform a successful load test. You can pick up a battery load tester for about 20.

  • 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 sure to leave the sensors for at least 15 seconds. Then, read the load tester and compare it to the number you calculated in step 4.

If the reading is 10 – 15% less than your calculated number, your battery can’t produce the power to run your engine.

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

If you find yourself with a faulty battery, you’ll need a battery replacement.

Fortunately, RepairSmith can help you with all your vehicle repair and car battery maintenance needs.

RepairSmith is a convenient mobile vehicle maintenance and repair solution. Here’s why you’ll want us to handle your battery 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 form for an accurate cost estimate of a car battery replacement and other repairs.

Final Thoughts

Performing a battery test 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’d prefer to leave it to the professionals, you can always rely on RepairSmith.

Just contact us, and our expert mechanics will be at your driveway to take care of all your car battery needs.

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RepairSmith RepairSmith is the easiest way to repair your car. Our ASE-certified technicians deliver quality car repair and maintenance directly to your driveway. We offer upfront pricing, online booking, and a 12-month, 12,000-mile warranty.

You Might Be Driving with a Dead Car Battery. Get a Battery Test.

Car batteries can last three to five years on average, but when yours dies, it usually fails without a warning.

The truth is you might already have a dead car battery.

Your battery could be 75% charged or 100% charged and still be at death’s door, the same way a cracked glass can be full of water. A fully charged battery could also be so aged, so sulfated and so weak that it can only hold a little bit of power for a brief period of time.

However, warm temperatures, a healthy engine and routine drives can mask that weakness. If the temps drop, a light gets left on or you don’t drive a few days, that’s when your car won’t start.

Not sure how to tell if a battery is dead? We got you!

Visit any place Interstate ® is sold, and let the pros give you a fast, accurate battery test.

It wasn’t that the battery died on a random day. Your battery’s been dead all along. The conditions just had to be right to show it.

Batteries wear down so slowly that you might not notice. That is, if a dying battery shows any signs at all.

Car Battery Hack: Ask for This Service With Every Oil Change

One simple service, available at most repair shops, could help you avoid the entire situation.

It’s called a car battery test.

It’s the most accurate way to tell if a battery is dead. While it’s not as well-known as getting your oil changed or brakes checked, it’s just as important. Getting a battery test routinely can keep your car ready and responsive every time you need it.

If you get into the habit, it’s harder for a dead battery to surprise you.

Battery tests are the real answer to “How do I know if a battery is bad?”

A car battery test analyzes how well your battery stores power. For the most accurate results, technicians use battery testers. They send a jolt of electricity into your car battery and study its response. It takes less than a minute to run a thorough analysis, and you get a simple readout:

“Good” means you don’t have to worry about a dead car battery for at least another six months. Winter and summer are the hardest seasons on car batteries, so test yours before then. For now, your battery is fine.

“Weak” or “Replace now” are your chance to avoid the stress of being late for work because you’re waiting for roadside assistance at the least convenient time. These results mean your battery is so weak that either cold temperatures, hard vibrations or not driving regularly could kill it.

Get a battery test at least twice a year to avoid dealing with a dead battery when you least expect it.

Hearing you have a bad battery can feel confusing. After all, you drove to the repair shop. The battery started the car just fine an hour ago, right? So, what exactly makes your car battery bad? The shocking truth is that 26% of all cars on the road today will need a new battery before the end of the year. That’s a lot of people driving around with failing or dead batteries under their hood.

They just don’t know it. They wouldn’t, at least without a battery test.

You don’t have to be surprised by a dead battery anymore.

Battery testing can change your car ownership experience. For decades, car owners had no choice but to wait for a dead battery to surprise them at the least convenient time possible. That era is long gone. Repair shops have the tools to take the mystery out of when your battery will die.

Here’s what you don’t know about how to tell if a battery is dead.

What makes a car battery dead?

One common misconception is that a battery test is just about voltage and charge. That’s like checking a tire’s air pressure to see if it has enough tread for a few years.

Voltage and charge can tell you if your battery is doing OK right now. However, they will not tell you anything about the battery’s overall health. A weak battery can be “100% full” right after you charge it, and the voltage may say it’s fine.

However, the voltage will drop again in a few hours. Then, if you try to start it, the amount of power won’t be enough to start a go-kart.

Bad battery symptoms don’t tell the full story.

But a battery test will! Get a free battery test at any Interstate All Battery Center ®.

Instead, you need to look at the battery’s cold cranking amps.

Cold cranking amps and how to know if a battery is about to die.

A dead battery can’t hold much power for long. A healthy one can store and deliver a lot of power.

That power is measured in cold cranking amps or CCA. Every car battery’s label lists the CCA rating a battery should have, and every vehicle needs a certain amount of CCA to crank the engine. If your 2012 Toyota Corolla needs 500 cold cranking amps to start, then you need a battery with at least 500 cold cranking amps, like the M-35 car battery.

Why cold? Car batteries really don’t like the cold. CCA shows how many amps your car battery should be able to deliver even if it’s 32 degrees below freezing. So, in other words, CCA shows how well your battery can work in the hardest possible conditions for a car battery.

Normally, a healthy car battery will show a higher CCA rating than what’s on its label. If it’s 70 F outside, a new 500 CCA-rated battery could show 600 CCA or more. If it’s 0 F outside, testing that new battery should show a rating matches the label.

The more worn out a battery gets, the less extreme the cold has to be to kill it. Instead of dying at freezing temperatures, a worn-out battery could die at 40 F. A severely weakened battery could die at 60 F.

  • The CCA on the battery’s label shows how well your battery should work.
  • The CCA from a battery test shows how well it actually does.

If the actual CCA is lower than what your engine needs, then it’s about to die. It’s a worn out, dying battery about to fail.

It’s time for a new battery because no matter how well you charge it, if the actual CCA is still lower than what your engine needs, it’s not going to start your car one day soon.

How do you test a car battery?

A battery test is not about checking corrosion or making sure the plastic case isn’t cracked. It’s also not about checking voltage or how charged the battery is.

The most accurate battery tests come from a conductance battery tester.

These testers send a signal through the car battery and measure how well it conducts electricity. If it meets any resistance, that’s a sign of weakness hidden inside. A conductance tester also registers voltage and state of charge.

Worried about a bad battery? Jump-start your own car.

Yes, you really can jump your own car with a handheld jump-starter battery. Get one and feel the worries melt away.

Another common battery test is with a load tester. These tests check how well the battery performs while drawing power from it. In short, a load test compares the battery’s stats from before and after pulling some amperage. One drawback: If you do a few load tests on the same battery, you can drain it flat.

You probably don’t have access to either a conductance tester or a load tester.

Unless you work in a repair shop, the best battery testing you can do is checking the voltage and state of charge. You can do both with an inexpensive multimeter or hydrometer.

Test a car battery with a multimeter.

A multimeter reads how much voltage your car battery has at the moment. It’s not a measure of how long your battery will last. That said, checking its voltage will show you whether your car battery needs to be recharged.

Test a car battery with a hydrometer.

This will take you back to your high school science labs. To use a hydrometer, you’ll need to open the top vent caps of the battery. (A flat-head screwdriver can pop them open.) However, if you have an AGM or a sealed, maintenance-free battery, you can’t use a hydrometer. (Also, don’t try to open AGM batteries.)

Like a multimeter, a hydrometer can only tell you the approximate state of charge, not how healthy your battery is.

Extremely Subtle Signs You Might Have a Bad Battery

The most obvious sign of a bad battery is that your car won’t start.

Batteries usually die without warning. Today’s engines are sophisticated. They’re smaller, lighter and easier to start than your grandparents’ cars. Today’s cars can compensate for a weak battery (but not fully recharge it.) which helps you get the most out of every battery. It also means that when your battery does fail, it didn’t have a chance to give you any warning.

How can you tell if a battery is bad?

Check before it actually dies. Visit any place Interstate ® is sold, and let the pros give you a fast, accurate battery test.

It just works one day and dies the next.

Another obvious sign: That battery warning light on your dashboard saying the voltage is low. That light could go away or never appear at all if you drive for more than 30 minutes every day. Voltage isn’t a sign of how much longer you can trust your battery.

However, if you’re observant, you can pick up some subtle signals from your car that the battery is about to die.

  • The headlights flicker a bit when you’re idling. As soon as you start the engine, turn on the headlights. What are they doing? If they’re not a solid steady beam, you might have a battery problem or a deeper electrical problem.
  • The car forgot your Bluetooth settings. Watch for electronic glitches like a window that hesitates before rolling down, a flickering cabin light or even the computer forgetting your Bluetooth connection or radio station. It may seem minor. It may also be a cry for help.
  • The idling as soon as you start seems rough. Your car draws power, usually from the alternator, to measure oxygen and fuel. In the first few seconds, though, your alternator’s barely gotten going. So the battery steps in, unless it’s too weak. And in that case, you’ll feel slight hitches or jolts that go away as soon as you get rolling. If you do, go get a battery test.
  • The engine start didn’t sound quite right. You know how your car sounds. You know what to expect. “Trust your hearing, Luke,” as a wise mentor almost said. If you can hear a slight pause that only lasts a quarter of a second, go get a battery test. You might simply need to recharge it.
  • The engine start is slow on cold mornings or nights. Weak batteries don’t do cold. A healthy, strong engine can usually compensate for a dying battery. If the engine doesn’t start instantly, then you might be seeing its first sign of weakness.
  • Everything seems better after you’ve been driving. If your car is a little glitchy or rough, but everything is always better after you’ve been driving for 20-30 minutes, that means your car’s electronics are mostly running on the alternator — and the battery’s not helping much. When the alternator’s not spinning fast (like when the engine’s rpm are low), the battery’s supposed to step in and support the other electronics. If everything’s better after the alternator’s been running hard, that means your car battery isn’t doing its job.

If you notice these little signs, it’s a safe guess that your battery’s dying. You can try a few ways to extend your battery’s life.

Why guess at all? You can visit your nearest repair shop or service lane and ask for a battery test.

Not sure where to look? We can recommend a few good shops to ask for your battery test. Of course, you can also get a free battery test at an Interstate All Battery Center near you.

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