BY Frank Massey A cross-section of repair challenges seen at my current workplace, Eldon Street Garage, probably reflect common issues dealt with by most workshops in our industry. With this in mind, it became increasingly apparent from the outset that little or no consideration was given to batteries. A simple battery test tool was available. However, none of the results were reliable in my opinion as nobody was checking to see if the battery was the correct specification for the vehicle it was fitted on. Basic test options A good place to start would be to review some of the basic test options and tools required for accurate assessment. 1: Check that the correct battery is fitted before testing. I found a high percentage were not correct. CCA rating was often too low, or the battery was of poor quality. I will expand on this later. I always prefer to fit the higher rated options available. 2: Always use a competent conductance test tool. Prices will range from £600-£1,000. Consider the cost as an investment in accuracy, easily recouped when replacing faulty batteries. Set the test parameters to the correct 28 AFTERMARKET APRIL 2023 TECHNICAL www.aftermarketonline.net A MONTH IN THE LIFE OF A VEHICLE TECHNICIAN Frank’s latest series continues, with even greater emphasis this month on battery testing specification required not the data from the fit label. It is essential that the battery is able to supply sufficient current for crank start without voltage starvation to the remaining vehicle systems. Network systems are especially voltagesensitive easily leading to false failures, as was seen in my article in the March issue. Common rail diesel requires a nominal crank engine speed in order to produce the minimum rail pressure required. Expect 300bar or more. If it is below 250bar it is possible the injectors will fail to operate. The same principle applies to direct gasoline injection systems, although pressures will differ. Nominal cranking speed is 150/175 for a calcium battery, or 200-plus for a EFB/AGM battery. 3: Please refer to Fig.1, which shows the Midtronics battery test tool. There should be a choice of in or out of vehicle test. When only a battery assessment is required, then choose out of car. Otherwise follow on screen prompts for cranking and charging performance. 4: Print the test result, repeat the test if a good battery requires charging. A calcium battery requires 16v to full charge and drive sulphation from the plates. Poor quality batteries have insufficient plate volume to store and supply the correct current. In order to meet the CCA rating the Fig. 1 Fig. 2 Fig. 1 Part Two
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