Auto Service World
Feature   January 1, 2009   by David Halpert,, Assistant Editor

Power To The Electrical Systems

How to deal with the complexities of batteries, starters and charging systems

While advances in technology have led to more robust vehicle electrical systems, it has also made them more complex. On-board computers, GPS devices, sophisticated audio systems, satellite radios and DVD players not only require more power to operate, but sometimes require more than a vehicle can seemingly spare. While batteries, starters and alternators are responsible for supplying power to all of the various electronic and luxury and entertainment gadgets inside, it is short-sighted to think these three systems are in isolation from all that they power. Rather, they and their components are part of a greater whole that represents everything electrical within the car.

Then & Now

Data communication has revolutionized how electrical systems work in today’s modern automobiles.

“When electrical systems were first developed everything was connected through wires,” says Mohammad Samii, owner of Sammy’s Auto Electric Service Inc. in Champaign, Ill., who specializes in the diagnosis and repair of charger and starting systems. “Data bus communication, the multiplex system through which data travels in vehicles, has allowed for circuits to reduce or replace wires.”

Modules are what control specific components in a vehicle, say the power locks, for example. They also function and communicate with other modules throughout the vehicle. While modules used to be connected to every other module through wires before, today they are connected to a central network, which not only takes up less space, but is also easier to manufacture, easier to maintain and provides greater flexibility to add and remove options without affecting the entire vehicle’s wiring architecture.

Now why are these modules significant to batteries, starters, or alternators? Simply, everything from changing gears to turning on a cooling fan is carried out by these modules; and a car’s starter, alternator, and battery are no exception -they are also connected with modules to the central network and thereby communicate with all the other modules in the car. What this means for the technician is that a fault in set of modules in a vehicle may be caused by a problem in the car’s starter, alternator or battery.

For example, if the car’s battery is low the car’s air conditioning system may stop working. On the surface, a technician might think the problem is with the air conditioning system, when in fact it’s a built-in failsafe mechanism where the module is telling the A/C system that it simply cannot spare the power from the battery.

So as a technician, you will have to do some out-of- the box thinking to trace a problem. Just because a problem seems to be with the automatic door opener, to give one example, it may in fact be a problem with the car’s battery or somewhere else in the electrical system.

Experts like Mohammad Samii say the first step is to get out one’s trusted scan tool and begin to narrow down where the problem might be and then to find out where in the electrical system or module the problem is originating. This is important as a module may be causing an electrical drain on the battery or that battery is causing a problem with the module’s operation.

Samii, who also is an expert training coordinator for the Automotive Parts Remanufacturer Association (APRA), says technicians can be trained in procedures that can help them pinpoint accurately where in the complex electrical system the problem is happening.

“There is no substitute for the right training,” he adds. “If you don’t know how to approach these systems there is no way you can repair them.”

Let’s take a closer look at the batteries for a moment. As mentioned before, what seems to be a problem with the A/C system is instead a problem with the battery. There are several tests that can be run to see if the battery is able to provide the right voltage so that everything runs as it is supposed to. The first thing often recommended is a state-of-charge test, with the electrolyte temperature at 25.7C and an assumed specific gravity of 1.265 cell average and 12.65 VDC open circuit voltage reading for a fully-charged, wet lead-acid battery. If you wind up with a car that has non-sealed batteries, you need to check the specific gravity of each cell with a hydrometer and average cells readings. For sealed batteries, you measure the open circuit voltage across the battery terminals with a digital voltmeter. If the state-of-charge is below 75 per cent, that battery needs to be replaced as it will just not produce enough power to keep the car’s electrical system operating properly. Another test that can be run is a load test. As well, when running any battery test, technicians are recommended to pay particular attention to the Cold Cranking Amp (CCA) values. Why? Many batteries are rated at Cranking Amp (CA) and not CAA, which means that a CAA battery is measured by the amount of amps at 18C for 30 seconds and a CA-ranked battery is measured at 0C for 30 seconds.

But what happens if the battery tests fine, but the technician is still getting electrical problems? Then it might be time to check the alternator. Again, it is recommend to do several visual checks first, such as making sure that there are no broken wires or a faulty belt. If that is alright, then one can check the alternator charging output using a voltmeter and seeing whether at idle the charging system produces 13.8 to 15.3 volts with the lights and other electronic accessories shut off. Another thing to be checked is the amperage, with new alternators today producing some 120-155 amps. Other things to check for are diode failure or to perform a circuit voltage drop test, which is a way to find hidden problems in the electrical system.

Why low-tech is sometimes better

More often than not a technician will discover that a problem with a battery, starter or alternator requires a very low-tech solution and results in replacing a damaged or broken part that affects the flow of electricity to the car.

“If the problem isn’t a result of typical wear from high mileage, the problem is often a result of neglect,” says Samii. If coolant or oil gets into the alternator, it can do further damage to a vehicle’s electrical system. A weak battery on the other hand can result in more power being drawn from adjoining systems, placing more strain on the alternator and starters.

Don’t overlook fuse links as well, Samii adds. Fusible links will puff up if there’s a short circuit inside. Loose or worn belts slip occasionally, preventing the alternator from either putting out enough current to keep the battery charged or putting out enough power for the entire electrical system. This can be corrected by a simple tightening of the belt just enough so that the pulley cannot be turned by hand. Similarly, too much belt tension may cause excessive strain on the drive bearing.

It is possible a defect lies in another component, such as the solenoid, cables, or battery. If a remanufactured starter is installed without a well-charged battery, good connections or proper cable size, it won’t perform correctly.

The importance of customer relations

While good communication skills and a friendly demeanour are expected when dealing with customers, what’s also important (if not more so) is getting the most accurate information possible without coming off as harsh or abrupt. As stated earlier, getting the most accurate information for sounding an electrical problem is the first step towards solving it.

Gale Kimbrough, technical service manager of Interstate Batteries System of America in Dallas, Texas advises service writers to not take everything the customer says at face value. “Don’t always go by what the customer is telling you, but also go by what they’re not telling you.”

Oftentimes, a customer is either too embarrassed to come forward with the truth, such as when a customer accidentally drains a battery overnight, for fear that their bill will be higher as a result.

This is why it’s import
ant to verify related symptoms when attempting to determine any problem with a vehicle’s electrical system.

The best advice to give when dealing with customers is to be fair with them and realize that their priorities, when it comes to automobile maintenance, may be different than yours. Take the time to listen and use that as an opportunity to educate them on what is happening with their vehicle and why the fix proposed is needed. You will find that a bit of patience and proper communications will result in getting them the right fix and your shop the revenue from a repair or replacement of a battery, starter or charger.



Reference List

ACDelco Canada

Interstate Batteries

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