One thing all electrical parts have in common is a higher warranty return rate compared to mechanical parts. The reason for this is two-fold: electrical parts are more complex, so there’s a greater chance the part may not work correctly when installed. But more often than not, the main reason why a brand new or remanufactured starter, alternator or ignition coil may be defective is due to misdiagnosis or mis-installation.
A high percentage of electrical parts that are returned by technicians because they were thought to be defective turn out to have nothing wrong with them. The reason the parts didn’t work right or solve the customer’s problem is because the vehicle was improperly diagnosed. Troubleshooting starting, charging and ignition problems isn’t easy and often requires a number of tests to isolate the fault. Sometimes hurried technicians don’t want to take the time to do all of these tests (or they don’t know how!), so they jump to conclusions and replace the part that seems most likely responsible for the problem. Sometimes the technician is right, and sometimes he’s not.
The engine won’t crank when the driver attempts to start the car. The technician tries jumping the battery, but the engine still won’t crank. He concludes that the starter is bad and replaces it with a new one. However, the engine still won’t crank. Obviously, it’s not the starter. With further diagnosis, the real problem may turn out to be a bad battery cable, starter solenoid, ignition switch, a damaged flywheel or even a seized engine.
The battery keeps running down, and the charging warning light comes on. The technician assumes that the alternator has failed and replaces it with a remanufactured unit. But the same problem still exists. He returns the reman alternator and demands a free replacement. He installs that unit, and it also fails to work. Now he’s really upset with what he perceives to be cheap reman alternators that he’s been sold. By the time he replaces the alternator for the third time, he may realize he’s misdiagnosed the problem. In cases like this, the charging problem may be due to a faulty external voltage regulator, a wiring fault, a missing or broken ground strap, bad battery connections or even a faulty PCM (as the PCM regulates voltage).
It’s no different with ignition coils. An engine won’t start because it doesn’t have a spark. The technician quickly concludes the ignition coil must not be any good. He doesn’t take the time to measure primary or secondary resistance. He doesn’t check to see if voltage is reaching the coil and is switching on and off. He just assumes that because there is no spark, the coil must not be working. He installs a new coil, and guess what? The engine still has no spark. The underlying cause may be anything from a bad ignition module or crankshaft position sensor to a faulty ignition circuit.
The point here is that no parts should be replaced until a technician has done his diagnostic homework and identified the fault with a reasonable degree of certainty. But that’s not a real-world scenario. Technicians are busy people, and they may make assumptions in order to save time. There are also a certain percentage of low-skilled technicians who may be good parts changers but they aren’t very good diagnosticians.
The Problem Technician
If your shop is making a lot of electrical returns, it’s probably a red flag that there is a technician who needs help. Maybe he needs to attend a good electrical clinic to upgrade his diagnostic skills. You don’t want to insult the guy by telling him he doesn’t know what he’s doing. The tactful approach might be to tell him about an electrical clinic a local jobber store is sponsoring or a course that’s being offered at the local community college.
The guy who’s making a lot of returns may also need some better diagnostic tools that would improve his odds of successfully diagnosing electrical faults. A digital volt-ohm meter is an absolute must for troubleshooting electrical problems. A device called a “logic probe” or “noid light” is also a useful tool for detecting signals in electronic circuits. There are also some really great handheld battery/charging system testers available today that can quickly and easily identify bad components that need to be replaced.
It Begins with the Battery
When addressing electrical problems, start with the battery. The battery provides current to crank the engine and to supplement the charging system’s output. Low battery voltage can cause hard starting, no starting and all kinds of weird electrical problems that may affect engine performance and vehicle operation. Computers, relays, ignition coils, fuel injectors and fuel pumps all require a certain minimum voltage to function properly. If the system voltage is low, it’s hard telling what might be adversely affected.
A good battery is one that can accept and hold a charge and deliver the rated number of amps on demand. A bad battery is one that won’t accept a charge or can’t supply its normal dosage of amps due to cell damage or deterioration. Good batteries can be recharged and returned to service, but bad batteries have to be replaced.
The level of charge has nothing to do with the battery’s condition. The level of charge only indicates how much juice is available at the moment, not how many amps the battery is capable of delivering when it is fully charged. Even so, you have to check the charge level to find out if the battery is low.
Some batteries have a built-in charge indicator. A green dot usually means the battery is 75% or more charged. A dark indicator (no dot) means the battery is low and needs to be recharged. A yellow or clear indicator means the electrolyte is low. The challenge here is that these types of indicators only give the condition of one of the six cells in a normal 12-volt battery. These state of charge “eyes” should never be used as the final indicator of a battery’s state of charge. A digital voltmeter is the answer here.
The most accurate means of measuring battery charge is with a voltmeter. A digital voltmeter is easier to read than an analog meter, but either will do. A fully charged battery should read 12.6 volts. A reading of 12.4 volts equals about a 75% charge and is good enough for further testing. Anything less means the battery is low and needs to be recharged.
A battery that is run down or completely discharged will need further testing to determine its condition. This can be done with a carbon pile load tester or one of several different types of electronic battery testers. Some electronic testers are basically automated carbon pile testers, while others use an entirely different technology.
A traditional carbon pile load tester simulates a load on the battery. When the load is applied, a good battery should still maintain a minimum voltage of at least 9.6 volts. But to get an accurate test, the battery must first be recharged prior to load testing if it is less than 75% charged. Recharging may take quite awhile, possibly even a full day if the battery is completely discharged.
When using a carbon pile load tester, the test load is typically set to one half the battery’s CCA rating or three times its amp/hour rating. You also have to compensate for temperature because a cold battery puts out fewer amps than a warm one. The load is then applied to the battery for 15 seconds while the battery’s voltage output is observed. If battery voltage remains above 9.6 volts, the battery is good and can be returned to service. But if it drops below 9.6 volts, it may be bad. To be sure, you can recharge the battery a second time and retest it. Also note that no attempt should be made to recharge or jump start a battery with low or frozen electrolyte because there is a risk of explosion. Even a frozen battery can tell a story. The only way a battery or cell within a battery can freeze is if it is completely discharged. If you ever see a frozen battery, you can feel safe in saying that it was discharged prior to freezing. If a battery has ever been completely frozen, it probably needs to be replaced.
A three-minute-charge test checks for a sulfated battery. This test requires slowly charging the battery at 40 amps for six minutes and then checking the voltage across the terminals with the charger on. If the voltage is above 15.5 volts, the battery is not accepting a charge. Slow charging for 20 hours can sometimes reverse the sulfate condition and save the battery, but if it can’t, the battery will have to be replaced.
Battery Conductance Testers
A faster way to check batteries is to use an electronic “conductance” tester. This type of technology does not require recharging the battery prior to testing and can give you an instant verdict in seconds even if the battery is fully discharged. This saves time that can be better spent replacing the battery if it is bad or recharging it if it is still good. It also increases the odds of correctly identifying batteries that are still usable and those that are not.
Battery testers that use conductance technology send an alternating frequency signal through the battery. Conductance reveals how much plate area is available to hold and deliver power. As a battery ages, its conductance declines. Shorts, opens and other cell defects also affect conductance, so measuring conductance gives an accurate indication of battery condition.
Most conductance testers not only analyze the battery’s charge and condition but also graphically display the battery’s cold cranking amp (CCA) capacity (which can be used to estimate the battery’s remaining service life). This can help the technician to sell a replacement battery prior to the battery failing on the road, which could potentially leave his customer stranded.
Other features that may be included with some conductance testers include the ability to analyze the charging system and measure the amps drawn by the starter while the engine is cranking. Some provide graphic displays and can store vehicle data for customer records or printouts. Others have a built-in voltmeter and test leads for checking battery connections.
A battery conductance tester also can be used to detect bad ground connections. This can be done by running a battery CCA test at the battery terminals, then repeating the same test using a ground point on the engine or elsewhere. More than a 25% difference in the CCA readings between tests indicates a bad ground. Check for loose, broken or corroded ground straps.
It is always a good idea to test a customer’s battery prior to installation to ensure your customer that the battery is good. This saves time and is always a good seed to plant with your customer. With this seed planted, and should the customer potentially return due to another electrical component problem, he or she usually understands that there is another problem and is open to discussion about fixing this problem rather than being angry about what they believe is a faulty battery.
Though most customers simply want a replacement alternator that’s the same as their old unit, some may benefit from upgrading to a higher output alternator.
High electrical loads are common in many late-model vehicles. It takes lots of amps to power the lights, electric defrosters, wipers, power windows, power seats, power liftgates, the ignition system, fuel injectors, fuel pump, cooling fan, A/C compressor, heater fan, heated seats, audio system and navigation system. Alternators can only generate so many amps, and their output depends on engine speed.
At idle when the alternator is turning slowly, output is reduced and may not be able to keep up with the demands on the charging system. Consequently, the battery has to make up the difference. The trouble is, the vehicle may not be driven long enough to fully recharge the battery. Short trips of 15 minutes or less – especially in stop-and-go traffic – may not be enough to maintain the battery at full charge. Over time, this can allow the battery to run down. It will also shorten battery life. This is why it is good for a person to have his or her battery checked with each oil change to ensure peak performance and battery life. A seasonal boost charge at low amps is always a good idea.
Alternators run hot, and the higher the amp load on the charging system the higher the internal operating temperature of the alternator. Stock alternators can handle normal amperage loads under normal operating conditions. But vehicles that spend a lot of time idling, are driven only for short distances, and may tax the alternator beyond its design limit. And when other aftermarket accessories are installed on a vehicle, the load may be more than the stock alternator can handle.
There are a number of everyday applications that may benefit from upgrading to a high-output alternator. One is trucks or SUVs that are equipped with a snow plow. The same goes for emergency vehicles that are equipped with extra lights and communications equipment. One of the hottest prospects for a charging system upgrade are “tuners” who have large, powerful sound systems in their vehicles.
High-output alternators are a premium-priced product, but provide increased value by extending alternator and battery life in high-load applications. High-output units are typically rated at 140 to 225 amps. The better units can produce 70 to 100 amps at idle, which is double the output of most stock alternators.
Higher outputs are achieved by rewinding starters and rotors, tightening up clearances and using an undersize pulley to spin the alternator faster. This really helps at idle, and it boosts the charging output throughout the rpm range. Most have heavy-duty diodes that can handle more current and heat and better bearings to improve durability. Some also have special heat-resistant ceramic coatings and insulation on critical parts. Chrome-plated, anodized and brightly painted housings are also available for those who want to dress up their engine compartment.
Some high-output alternators are direct bolt-on replacements for the OEM alternator, but some require modifications to install (changing or relocating brackets and splicing wires). Another change that’s needed is a heavier gauge wiring harness to handle the increased load. 2GA wiring is recommended for 120 to 140 amp alternators, and 1/0GA wiring is needed for 140 to 225 amp alternators. A replacement wiring harness may be included with the high-output alternator.