Battery starting charging system maintenance

Checking the battery systems can save you comebacks from customers down the line.

No-crank or slow-crank concerns are among the most common customer complaints we deal with as automotive service professionals. If you can verify the concern, these are relatively easy to diagnose when compared to the myriad of possible engine performance issues. A technician with a sound electrical background often can pinpoint the problem quickly and perform a repair that returns the vehicle to reliable service.

In a perfect world, all of our repairs would go that smoothly. An alternative scenario is when a vehicle has undergone related (or unrelated) repairs and then suffers a no-crank or slow-crank concern after it has been returned to the customer. The customer might not have indicated that there was a cranking problem when the car came in, but the engine won't turn over now that the vehicle has left your shop.

A common time for this to happen is when the weather has just turned cold in the fall. The customer might even blame you for the problem, seeing as you were the last one to lay a wrench on their car. Whether you should have caught this before it happened is a matter of debate. However, it might be worth reviewing your shop's procedures to determine if simple adjustments can be made that will reduce these types of comebacks.

Selling preventive maintenance might be an answer to this dilemma. While it won't catch every cranking problem that comes through your shop, it almost certainly will reduce comebacks and increase customer satisfaction. The services we are talking about are battery maintenance and testing, as well as inspection and basic tests of the starting and charging systems. If presented to your customer as an inexpensive way to increase vehicle reliability, it might even be an easy sell. Here is a short list of items you should pay attention to when performing battery, starting and charging system maintenance.

Battery Service and Testing

Let's start with the basics. A quick visual inspection of the battery probably will tell the story of how well the vehicle has been maintained. If there is significant corrosion on top of the battery, it is probably best to remove it for a thorough cleaning. Before removing the battery cables, install a memory saver device on the vehicle to avoid losing radio presets and the like. Keep in mind that the positive cable terminal should be wrapped in electrical tape or the equivalent to prevent it from touching ground.

Disconnect the hold downs (if they exist) and carefully remove the battery using a lifting tool. Spray down the battery case with a can of cleaning solution or use baking soda dissolved in warm water to neutralize any accumulated acid. Use a parts brush to loosen soil and debris while rinsing with clean water. Now also would be a good time to use a battery brush to clean the posts and the cable terminals. Continue rinsing the battery case and then dry the top off with a clean shop towel.

If a large amount of corrosion has accumulated around the battery tray, you might consider removing the majority of it using a shop-vac before finishing the job with battery cleaner. Regardless, pay close attention to where the water will flow when you clean the battery tray. Some vehicles have modules and wiring installed near the battery that could be damaged if you're not careful. While you're in the neighborhood, take a good look at the condition of the battery hold down. Do your best to keep your customer from going out the door with a missing or makeshift battery hold down! Automotive batteries rely heavily on these to prevent damage due to vibration and impacts. Certainly, reliability of the entire electrical system is compromised if the battery is allowed to move wherever the laws of physics want to take it.

There are several different approaches when it comes to battery testing. While carbon-pile load testing still works, it is highly dependent on the skill and judgment of the technician. Today's computerized battery testing technologies do what they can to limit the variables that tend to skew test results. The tester will ask the technician to input basic information, such as the battery's Cold Cranking Ampere (CCA) rating, the battery type and whether the test will be done with the battery in or out of the vehicle. Once those pieces of information are put in, the machine begins the test process and will prompt the technician if anything further needs to be done to complete the test.

The obvious benefits for the shop owner are that the tester brings consistency to the battery testing process and will yield a go/no-go decision on the condition of the battery. Past that, the test results often can be printed out to attach to the repair order, giving the customer some assurance that the test is objective and authoritative.

If the battery tests bad, it is extremely important that it be replaced with a unit that is the equivalent of what originally came with the car. Most battery manufacturers provide application guides for their products, and these can be used to determine an appropriate replacement. Keep in mind that the new battery should meet or exceed the original CCA rating and have the same external dimensions.

Carefully install the new battery, being sure that no debris are caught under the battery case, and gently tighten the battery hold down. Reconnect the battery positive cable first, then the negative cable. At this point, you can remove your memory saver device from the vehicle. Battery terminal coating can be applied to top-post connections as a final step before moving your attention to other areas of the electrical system.

Charging System Inspection and Tests

When inspecting the vehicle charging system, think about what the system needs in order to do its job. Above all, it needs to have a battery and an accessory drive that are both in good condition. Because we already have discussed the battery, let's go over a few pointers on what to look for when inspecting the vehicle's accessory drive.

The generator (a term now used interchangeably with alternator) likely is driven by a serpentine belt with an automatic tensioner. Start by pulling on the longest span of the belt and watching the tensioner operation as it moves up and down. The tensioner arm should move smoothly throughout its travel and should not rock around during this exercise. If it hangs up or appears loose on its pivot, it is time for a replacement. It will pay to remove the belt at this point and inspect it carefully, looking for wear and any signs of pulley misalignment.

If a new belt is required, take a moment to clean all the pulley grooves with a stainless steel brush. Just before installing the new belt, spin the generator and listen for any unusual noises that would betray bad bearings.

With the belt reinstalled, it is time for a functional test of the charging system. If you have a carbon-pile load tester and an inductive ammeter, you could do a maximum output test of the generator and then compare the results with specs. This would involve clamping the inductive ammeter on to the generator's B+ cable (the largest cable attached to the generator), then running the engine at 2,000 rpm and placing a load on the battery equivalent to the generator rated output. The generator's tested output should be within 10 percent of the specified amperage; if it is putting out less, it might require further diagnosis.

Note that this procedure is not necessary if you own a battery-starting-charging system test machine. You can test the charging system separately, or run a comprehensive test that will check everything all at once. The efficiency of this setup is very attractive, as a complete picture of the vehicle electrical system can be acquired very quickly. This type of tester also can do a check for abnormal generator ripple, indicating a damaged rectifier bridge. Verifying the repair is also quick and easy, and a before and after print out of vehicle tests can be provided to the customer.

Starting System Checks

The best condition to check a vehicle's starting system is when the engine is cold, preferably after it has sat outside overnight. The combination of the engine being harder to turn and the battery capacity being reduced in the colder temperatures can be an excellent stress test of the system. Unfortunately, this rarely is practical and therefore we must rely on testing that is performed in the shop.

A starter current draw test can be helpful, and many computerized testers will do this if you have purchased the optional current clamp. Make certain the battery is charged and in good condition before running a starter current draw test. Also keep in mind that the most common reason for failure of a starter motor is insufficient voltage being provided to it. That being said, starting system maintenance is intimately tied to the battery and the connections leading to it. If you have done a good job of maintaining the vehicle's battery and its connections, this will go a long way towards keeping the starting system in tip top condition.

Recap

The battery, charging and starting systems of any vehicle are interrelated and dependent on one another to work correctly. Neglect of any one of these systems can lead to poor vehicle performance and reduced reliability. Selling preventive maintenance of these systems to your customers will reduce comebacks while increasing both revenues and customer satisfaction.

Tony Martin is an associate professor of automotive technology at the University of Alaska Southeast in Juneau, Alaska. He holds Canadian Interprovincial status as a Journeyman Heavy Duty Equipment Mechanic. He also has 19 ASE certifications, including CMAT, CMTT, L1 and L2.