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How do you load a test on an alternator?
Read the voltage on the meter – Start the engine and observe the voltage on the meter. The voltage should read a minimum of 13 volts. A good alternator should put out between **13.5-14.5 volts. Stress test the alternator – Place a load on the alternator by turning on the headlights, the radio and the air conditioning.
Do I disconnect the positive or negative to check the alternator?
You can check the alternator by simply starting your car and then disconnecting the negative battery cable. Be careful doing this, though, because there are a lot of moving parts in your engine compartment that could cause injury.
How do you inspect and test the alternator output by carrying out a no load test?
Battery No-Load Test Ensure that the ignition switch is turned OFF. Connect a tachometer to the engine by following the manufacturer’s instructions. Using a Digital Volt Ohmmeter (DVOM) measure the voltage across the positive (+) and negative (-) battery terminals. Note the voltage reading for future reference.
What is normal alternator voltage output?
between 13.9 and 14.8 volts
A good alternator should maintain battery voltage between 13.9 and 14.8 volts (14.2 is optimum). Even worst-case, with all accessories turned on, there should be at least 13 volts at the battery.
Can a bad alternator drain a battery while the car is off?
But when the engine is off, the alternator can’t recharge the battery, allowing little electrical mishaps to drain your battery entirely. The battery strain caused by these electrical whoopsies is known as a parasitic draw.
How to test an alternator?
How To Test An Alternator 1 Remove battery terminals and make sure these are 100% clean from and buildup of corrosion. 2 Test the battery voltage, at rest this should read between 12.5 and 12.8V on average. 3 Check over all vehicle grounds to ensure these are up to par.
What should I do after installing a new alternator?
When a new alternator is installed, check the battery voltage and use a battery charger to bring the battery up to full charge before returning the vehicle to your customer. Also, start the engine and use your DVOM to check the charging output of the alternator. Don’t assume everything is working OK just because you bolted in a new alternator.
How much does an alternator load tester cost?
Proper load testers, normally found at professional shops and dealerships, cost around $2000 on the low end, not exactly cheap enough for the average DIYer. But there are still a few low-budget methods you can try to give you a good idea of the health of your alternator.
What should the voltage be on an alternator on a multimeter?
Testing an AlternatorIf the alternator is working well, your multimeter should read somewhere in the vicinity of 14 volts (typically 13.8-14.2). If it is reading excessively higher than 14 volts (greater than 15 volts), it is possible that the voltage regulator on your alternator is faulty or going bad.