EVERYTHING YOU NEED TO KNOW FOR SUCCESSFUL BATTERY SERVICING A WHITE PAPER ON BATTERY TESTING More than a third of breakdown incidents attended by roadside technicians from the Dutch and German automobile associations ANWB and ADAC are as a direct result of problems with the battery, with many of these vehicles having been serviced regulary. Can garages prevent vehicles from breaking down by performing preventive maintenance? How? To find out, we went in search of answers to four common questions about battery servicing: 1. Why test batteries? 2. How do you test batteries and the charging systems? 3. What can go wrong? 4. What do you need for a good battery test? 1 Why test batteries? The German automobile association ADAC has published a list of the types of incidents attended by its roadside technicians on its website. Unfortunately, the categories into which the breakdown statistics are broken down differ from year to year. Nevertheless, you can still learn a lot from the figures provided. For example, 31.7% of motorists who called out the ADAC in 2012 had a battery problem. In 2013, this figure rose to 33.1%, and by 2015 it was 35.7%. This is therefore more than one third of breakdowns, and rising. If we include failures due to problems with the alternator or starter motor, this figure rises by some additional 10 percentage points. This means that nearly half of all car breakdowns in Germany are due to either battery, starter motor or alternator problems. Nearly half of breakdowns are due to either the battery, starter motor or alternator The ANWB offers free battery tests at members homes In the Netherlands, the ANWB presents its breakdown statistics in the form of the Top 10 Vehicle Breakdowns. Battery problems has for years held the number one spot. The ANWB website states: If you want to avoid a nasty surprise when the temperatures plummet, ask about our preventative battery checks. Members requesting this service should have a roadside technician at their home within the hour. It then takes the technician fifteen minutes to check the battery, alternator and starter motor (the latter two occupy positions 3 and 6 in the Top 10 Breakdowns). The cost of this battery check? 0.00. What s more, if the battery is in poor condition, the roadside technician will gladly fit a new one there and then. Thanks to this preventive testing, and of course thanks to roadside assistance, the ANWB sells tens of thousands of batteries each year Tens of thousands of batteries, is that revenue that the garages are missing out on? Probably not, since this figure will also include cars that only ever visit a garage for the compulsory annual vehicle safety test. And batteries can suddenly give up the ghost in cars that receive regular maintenance too. However, it is much more common for batteries to deteriorate gradually. The capacity of the battery declines slowly over time.
Unusually high discharge accelerates the process, as does hot weather. So although battery problems start in the summer, you won t notice until winter. At low temperatures, the capacity of a worn-out battery is not sufficient to start the engine, and that s when motorists can find themselves forced to call out a breakdown service. Sometimes low temperatures aren t even necessary. Many motorists call out breakdown services due to battery problems in the summer too. In all these cases, a battery test in the months prior to the breakdown could have shown that the battery was weak, and prevented a roadside failure and more importantly an unhappy customer. Battery problems start in the summer, but you won t notice until winter As shown in the video about battery checks on the ANWB website, ANWB roadside technicians use Midtronics battery testers. Midtronics also has its own statistical data: An average of 17 out of every 100 batteries tested by garages need replacing. Of those 17 customers, an average of 13 actually buy a new battery. In short, every 100 battery tests equal 13 battery sales on average. Varta s statistics are slightly more optimistic: 1 in 5 batteries tested is in bad condition. And because 7 out of 10 customers follow the advice of the garage, 1 in 7 batteries are replaced immediately. ABOVE: BATTERIES ACCOUNT FOR MORE THAN A THIRD OF BREAKDOWNS IN GERMANY. ADD TO THIS PROBLEMS WITH THE STARTER MOTOR OR ALTERNATOR, AND IT IS RESPONSIBLE FOR ALMOST HALF OF VEHICLE FAILURES.
It s a matter of trust However, at garage and diagnostics specialist DTS in Lopik, battery sales are not the main motive for testing the battery of each car that enters the premises: Every car we service must always fire and start. Even in winter, says DTS owner Willem Sluijs. Customers need to be able to count on that when their car comes here for servicing. It starts, doesn't it?! However, there are some DTS customers who respond with, What do you mean the battery's no good? It starts, doesn't it?! When Willem shows them the test report and explains that this might not be the case on a cold winter's morning, he is usually asked to fit a new one. But not always: If the customer still says no, then I put on the bill that we tested the battery and it was found to be in poor condition. I've received several early morning calls from such customers, saying: Er... I know you mentioned this, but my battery's dead. ABOVE: 17 OF EVERY 100 BATTERIES TESTED GET THIS RESULT, SAYS MIDTRONICS. 13 OF THESE 17 CUSTOMERS AGREE TO REPLACE THE BATTERY. AND THE OTHER FOUR? THEY RING UP ON A COLD WINTER'S MORNING: ER... I KNOW YOU MENTIONED THIS, BUT MY BATTERY'S DEAD. LEFT: BATTERY CHECK? THE ANWB WILL GLADLY COME TO YOUR HOUSE TO TEST YOUR BATTERY 2 How do you test a battery? In the past, batteries were tested with a hydrometer. A hydrometer measures the specific gravity (or better: the specific density) of the electrolyte. However, since the advent of maintenance-free batteries that do not have fill caps, this is not possible anymore. But this need not be a cause for concern. After all, the specific density of the electrolyte only indicates the state of charge of the battery. If a car battery is 100% charged, then the specific density is high (1.28 g/ml). If a battery is 80% charged, the specific density is 1.245 g/ml. Fascinating, but you can also find out the state of charge quite easily using a digital voltmeter. A 100% charged battery has an idle voltage of 12.7 V, while an 80% charged battery has an idle voltage of 12.5 V. If a battery has an idle voltage above 12.5 V, it is considered to be charged. Battery manufacturers recommend charging straight away if the idle voltage is 12.4 V or lower. If the battery repeatedly has a low state of charge, or is in a low state of charge for a prolonged period, this will lead to sulfation. This irreversible process has a negative impact on the state of health of a battery.
Dent in the tank This state of health says something about those parts of the battery plates that are still active. A battery with a poor SoH is like a fuel tank with a big dent in it. Even if you fill it right up (SoC = 100%), you are not going to get very far. A battery with a bad SoH will not deliver the expected cold cranking amps. (Read more about SoH in the inset paragraphs Modern cars make new demands on batteries on page 11.) In short, the state of charge does not indicate the health of a battery. It is the state of charge and state of health which together determine whether a battery can deliver enough amps on a cold winter morning to get the engine turning over. Hence why together the SoC and SoH are called the SoF, or state of function. The state of charge and state of health combined determine whether a battery can deliver enough amps on a cold winter morning to get the engine turning over Conductance measurement Therefore, a good battery tester does not only measure the idle voltage, but also the SoH. The SoH is measured according to the conductance principle. The tester measures the internal conductivity, which tells it the internal resistance of the battery. This value says something about the amounts of plate material that are (still) active in the battery, and is therefore a good indicator of the state of health of the battery. Connect the clamps to the terminals We watch Willem Sluijs to see how he performs a battery test. First, you need to connect the tester: Preferably directly to the terminals, says Willem. And why not to the auxiliary or jump start terminals, which are easier to reach? The internal resistance of this battery should be about 5 milliohms. The resistance of the cable between the negative pole and auxiliary pole is perhaps 1 milliohm. It could therefore affect the result of the measurement, but only in borderline cases, batteries that are on the verge of failing. If you can t access the battery, just measure using the auxiliary poles. Set up the tester Then it is time to set up the tester. You need to tell the tester what type of battery it is, whether it s being tested inside or outside the vehicle, and whether it s an AGM, EFB, gel or conventional battery. Each different type of battery requires a different test algorithm. For instance, if it's an EFB battery and your tester doesn't recognize that type, you won't be able to get a reliable measurement of that battery. Then the tester asks for the specified cold cranking amps (CCA) and the measurement standard used to obtain this value. This could be DIN, IEC, EN, SAE or JIS: You can find this information on the battery. Sometimes in the form of an ETN code, or often as a QR code, which you can read with your phone, Willem explains. Surface tension Now the tester will take a measurement: It takes a conductance measurement and measures the battery voltage. This affects the conductivity. But watch out: The battery voltage may be higher if the car has just been driven. If the tester doesn t take this into account, you need to remember to turn on the lights before the measurement is taken, so you remove the surface tension. Midtronics testers will help you with this. Battery OK Then the results: This battery has a CCA value of 650 A (EN). We measure 623 A (EN) at 12.8 V. The tester is satisfied: Battery OK. Starting and charging system Willem: The SoC and the SoH are both fine. That means the battery doesn t need to be recharged and you can assume that the charging system is working properly. He tests it all the same. Willem connects the current clamp and then sits behind the wheel, making the most of the battery tester s long cables.
Willem starts the engine and follows the instructions on the screen. The tester measures the charging system under four different operating conditions: idle speed, idle speed with electrical consumers, increased speed and increased speed with electrical consumers. Just as he thought: the charging system of this vehicle is in good working order. With such a good reading, Willem could easily have bypassed the charging system test. But don't be too quick to do that, because a defect in the charging system can lead to a faulty battery. (See: Faulty charging system in practice, inset paragraphs on page 8) Building trust Is that the end of the battery test? The technical part, yes, says Willem. But we re not finished yet. We always let the customer know that we've tested their car battery and charged it where necessary. So we don't just inform the customer if their battery is dead, we also let them know if their battery and charging system are functioning properly. IF THE HOOD IS OPEN ANYWAY, IT DOES NOT TAKE LONG TO CARRY OUT A BATTERY TEST THE TESTER NEEDS TO KNOW WHAT KIND OF BATTERY IT IS. THIS BATTERY'S SPECIFICATIONS ARE CLEARLY STATED, BUT IF THIS IS NOT THE CASE THEN THE 9-DIGIT ETN CODE TELLS YOU WHAT YOU NEED TO KNOW IN ANY CASE. IF THE CODE BEGINS WITH A NUMBER BETWEEN 501 AND 799 THEN IT IS A 12 V BATTERY. THIS FIGURE MINUS 500 INDICATES THE CAPACITY OF THE BATTERY. IN THIS CASE, 570-500 = 70 AH. THE SECOND THREE DIGITS GIVE INFORMATION ABOUT THE DIMENSIONS AND THE LOCATION OF THE TERMINALS, AMONG OTHER THINGS. MULTIPLY THE LAST THREE-DIGIT NUMBER BY 10 AND YOU HAVE THE COLD CRANKING AMPS. IN THIS CASE: 10 X 065 = 650 A (EN)
LEFT: BATTERY OK. IF THIS IS NOT THE CASE, OR IF THE TESTER SAYS OK PLUS CHARGE, THEN A STARTING AND CHARGING TEST IS IN ORDER. WILLEM ATTACHES THE CURRENT CLAMP. RIGHT: THE TESTER GIVES INSTRUCTIONS SO THAT IT CAN MEASURE AT IDLE AND INCREASED SPEED, WITH AND WITHOUT ELECTRICAL CONSUMERS. FAULTY CHARGING SYSTEM IN PRACTICE We had one customer who was on holiday 20 km from our garage and who had a dead battery, says Willem Sluijs. Totally empty, nothing worked. There was another car nearby that had jumper cables, but they couldn't even jump start it. I advised the owner of the other car to let it run for half an hour with the jumper cables connected. Eventually the car started and the customer drove straight to us at DTS Lopik. The car had an AGM battery, a start-stop system and a so-called smart charging system. This was important in arriving at a diagnosis, because that system sometimes chooses not to let the alternator recharge, explains Willem. "If you test the charging system at that moment, the tester won't detect a ripple: it thinks the engine isn t running and will start to ask you to start it. How did the battery get so empty? Willem: We always want to start a diagnosis with a good battery. So to begin with I connected the battery to the diagnostic charger. If this is unable to determine the SoH because the SoC is too low, it will charge the battery using a smart charge curve. After a certain period of time it will re-test. In this case, the battery tester continued to reject the battery. Was the charging system faulty? After consulting the customer, we fitted a new AGM battery. Problem solved? No, because what was draining the battery so much? Was the charging system faulty? After testing, this proved to be the case. As a diagnostics specialist, Willem wanted to be 100% sure. So he went for a test drive with a scope and a diagnostic tester. During the drive, the voltage declined gradually, and although the diagnostic tester sometimes expected a charging current of 80 A, the actual charging current did not exceed 10 A. A new alternator solved the problem. With this kind of case, if you just replace the battery then the new one will be dead soon too, and you ll have an unhappy customer knocking on your door.
DTS IN LOPIK TESTS THE BATTERIES OF EVERY CAR THAT ENTERS THE GARAGE. AS A DIAGNOSTICS SPECIALIST, THE COMPANY USES A DIAGNOSTIC CHARGER AS WELL AS A BATTERY TESTER. OFTEN YOU HAVE TO CHARGE THE BATTERY BEFORE YOU CAN TEST IT PROPERLY, EXPLAINS DIAGNOSTIC TECHNICIAN WILLEM SLUIJS. THE DIAGNOSTIC CHARGER HAS A TEST/LOAD/CHARGE CYCLE DURING WHICH IT CONTINUALLY CHECKS HOW THE BATTERY REACTS AND RECOVERS AND HOW MUCH POWER IT ABSORBS. A DIAGNOSTIC CHARGER IS THEREFORE ABLE TO RECOGNIZE PROBLEMS THAT MOST TESTERS WOULDN'T PICK UP. 3 What can go wrong? It's still going! Willem Sluijs has had customers who ignored his advice to replace the battery and then regretted it later on a cold winter's morning. Other companies have had different experiences: Six months ago, you advised me to replace the battery. I didn t do it. And look, it's still going. Clemens Streng from battery tester producer Midtronics comments: In programming our testers, we don't take any risks with the recommendation to replace the battery. Recommending replacement and then finding out that the battery is still working is annoying. But advising a customer that a battery is OK only for it to then fail is unacceptable. The customer can take the risk of ignoring the recommendation to replace the battery. He doesn't know how long he can drive around on it until it's too late. The breakdown statistics speak for themselves. The advice is intended precisely to save him the annoyance of breaking down. It provides a bit of security. And the vast majority of motorists are willing to pay for this. Contradictory test results Occasionally the following scenario occurs. You test a battery and the result is: Replace, you test it again and the result is Battery OK. How is that possible? And more importantly: What do you do? Clemens Streng answers on behalf of Midtronics: That can happen, but I want to emphasize that these are exceptional cases. It may be that the state of charge is good, but that the CCA value is approaching the limit between Replace and Battery OK. A small variation in the measurement, for example in the connection or the temperature of the battery, may just tip the result one way or the other. But in any case, it s important to understand that the battery is approaching the limit between OK and Replace. It has been downgraded from a properly functioning battery to a battery that just about meets the minimum specifications. The battery will still be able to start the vehicle, but it will probably fail in the short term. That's why we advise customers who get this result to replace their batteries. New battery fails too Once upon a time, replacing a battery was a simple job. Those days have gone. Why is that? Modern cars make new demands on batteries (see inset paragraphs below). As a result, fitting the right battery has become even more important. If a car needs an EFB or AGM battery, but a conventional battery is fitted, the battery is highly likely to fail prematurely. If the new battery is not registered via the diagnostic tester, then the start-stop system will not work as intended.
AGM BATTERY FROM A MERCEDES CAR WITH A START-STOP SYSTEM. IF THE NEW BATTERY DOES NOT MEET THE REQUIREMENTS OF THE OEM THEN THE BATTERY IS HIGHLY LIKELY TO FAIL PREMATURELY. MODERN CARS MAKE NEW DEMANDS ON BATTERIES Car batteries used to be called starter batteries. They started the engine, causing the SoC to dip briefly. The alternator quickly brought the SoC back up to 100%, and for the rest of the journey the battery was merely a passenger. That all changed when cars (starting with the Mercedes S-Class) began to be packed with sensors, actuators, displays, heaters and computers. The power required by all these consumers was sometimes so great that the battery had to help out. As a result, the battery ended up in a partially discharged state far more frequently. This was at the expense of the service life of the starter battery. The AGM battery offered a solution. This battery is much more resistant to partial discharge. With the advent of start-stop systems, the cyclic load on batteries was increased even more. The engine and the alternator shut down at traffic lights and it is up to the battery to keep all power consumers going. When the car accelerates, all the energy has to go to the wheels and the alternator is not involved; but when the car brakes, the alternator goes the extra mile to regenerate braking energy. There needs to be space in the battery for this energy. And so the SoC of a battery in this type of car is often lower. Conventional batteries cannot handle this, but AGM batteries can. Cold cranking amps and reserve capacity This development changed the meaning of the concept of SoH (state of health). Previously, a battery was healthy if it could supply sufficient cold cranking amps. Now, as well as supplying the CCAs, it also needs to have sufficient reserve capacity to keep all the consumers going when the start-stop system is active. Midtronics points out that modern testing algorithms also diagnose a battery's reserve capacity. EFB as a cheaper alternative However, AGM batteries also have disadvantages. Due to their construction, they can be less heat-resistant. That is why you often see them outside the engine compartment. And AGM batteries are expensive. Both of these disadvantages are difficult for smaller cars such as the Fiat 500 with a start-stop system to deal with. So, the industry came up with an alternative for this type of car, the EFB battery. EFB batteries are significantly cheaper than AGM batteries and better able to withstand heat, but they can be less able than AGM batteries to withstand cyclic loads. Register with diagnostic tester All the additional consumers, a start-stop system and a smart alternator can only function properly if the BMS (Battery Management System) knows the battery's state of charge. Hence the sensor on the negative terminal. This monitors the temperature, SoC and decreased capacity. And of course, the BMS needs to know the battery's specifications. These are shown on the battery label in the form of a code. When a new battery is fitted, this code needs to be registered via the diagnostic tester.
WHAT ARE THE COLD CRANKING AMPS AND WHAT IS THE CAPACITY OF THIS BATTERY? A QR AND SMARTPHONE PROVIDE THE ANSWER 4 What do you need for a good battery test? What is the best way to carry out successful battery tests in your garage? Make sure you have the right tools, says Clemens Streng of Midtronics. First of all, you need a complete tester. This should be able to deal with different battery types, such as AGM and EFB, test the starting and charging system, and use up-to-date software and the correct algorithms. Our latest battery testers of course meet these requirements. A printer is useful for communicating with customers, who like to see a printout showing the test results. With our DSS tablet tester you can go one step further. This enables you to send the test data to your garage management system. Testing ánd charging As well as testing, you also need to be able to charge, if only because you don t want a car with a half empty battery leaving your garage. By testing you can determine the status of the battery. By charging you can extend the life of the battery. In this way, you're maintaining the battery, says Streng. A charger can also serve as a power backup during a battery change and obviously the charger must be suitable for AGM and EFB batteries. The best type is of course a diagnostic charger, like the one Willem Sluijs uses. In some cases, you can only assess a battery once it has been charged, and on those occasions a diagnostic charger is very quick and easy to use. The successor to the device that Willem uses is called a GRX-3000. Tires, wipers, oil and battery Include it in your process As well as tools, you also need knowledge: Due to the sophisticated electronics on board and the different types of batteries that exist nowadays, testing and replacing batteries has become much more complex. But Dutch and Belgian automotive technicians are well trained. They re up to the job. Streng points out another bottleneck: When a car is serviced, the technician will change the oil, check the tires and windshield wipers and various other things. But many companies don't include battery maintenance in the process. If you want to make a go of battery maintenance, include it in your process: tires, wipers, oil ánd battery.
WILL A BATTERY TESTER PAY FOR ITSELF? We know from research that if you proactively test 100 batteries, 17 will need replacing and you ll sell 13, says Clemens Streng of Midtronics. If you carry out 25 battery tests per week and clear 30 per battery, you ll sell 169 batteries a year and clear over 5000. Even an advanced diagnostic charger will pay for itself in two to three months. Thanks to DTS Lopik. Photos: ADAC, ANWB, AMT