An alternator (centre)
You can catechism batteries with a voltmeter or multimeter. Depending on how it reads with and without a load, you can cinch if your alternator is failing to charge the battery when the engine is running, or provided the battery is the difficulty.
Instructions
1. Bound your engine for half an period to fully charge the battery.
2. If the voltage drop is high, you may want To cleanse the terminal.
A voltmeter, but, has a eminent resistence, which is why you won't short the battery.
4. Turn off the vehivle ignition and all electrical devices, prize the radio, headlights and air conditioner. Remove the ignition vital to prevent any course from completing.
5. Touch the voltmeter's metal probes to the battery: the brunet probe to the contradiction (-) terminal, the cherry probe to the decided (+). It doesn't episode yet which pathway you end it, however this hook you'll amuse a confident reading.
6. Adjust the voltmeter's arrayal to study between Eight and Fourteen volts. Provided the demonstrate reads between 12.5 and 12.8 volts with the transmission off, this is a good sign that the battery gets sufficiently charged. Below Twelve is not satisfactory and suggests a charging problem. (Below Ten is almost dead.)
7. Insert the key and turn on a turn signal or the hazard lights. Don't turn on the engine. Test the voltage again. The battery should still manage around Twelve volts under this load. This tests the internals of the battery, so if the test of the alternator fails you know it's not the battery's internals that are the cause. The battery should stay above 9.6 volts under load. If not, the solution is to restore it with a three-step recharger and Epsom salts to reverse any sulfation.
8. Turn on the engine. This is when the alternator starts working, converting gasoline energy into stored battery energy. Test the battery's voltage again. A reading of Thirteen to Fourteen volts indicates the alternator is working. Less than this indicates the alternator has a problem--if you haven't found other problems with the battery up to this point. Voltage above 15.5 means the battery isn't accepting the charge. This is a fault of the battery, not the alternator.
9. Check voltage drops along connections too. The voltage difference between alternator and battery should be less than 0.1 volts. More than 0.4 volts means a problem like dirt, corrosion or a loose connection. Check the voltage drop between the battery terminal and the clamp that goes on the battery terminal too. Locate your voltmeter to DC, owing to vehivle batteries are sources of administer in fashion.3. Establish the metre to "Volts" provided you are using a multimeter. Otherwise, in an ammeter setting, the resistence could be very low and you could seriously damage your battery.
