How do you test a alternator parasitic drain?
How do you test a alternator parasitic drain?
To do a quick alternator drain power check using your digital multimeter, go to the section Bad Alternator Diode Test below. Then, if your alternator passes the test, do a battery check using a hydrometer tool as described in the Car Battery Hydrometer Test section.
What does it mean if your alternator is draining your battery?
If disconnecting the power cable from the alternator and stopped the current drain on your battery you should have seen a reading. This does not necessarily mean the alternator is bad. See below circled in yellow.
How can I tell if my alternator is bad?
If disconnecting the power cable from the alternator and stopped the current drain on your battery you should have seen a reading. This does not necessarily mean the alternator is bad. See below circled in yellow. The meter is working, I did get zeros when I turned it on.
How many diodes are in a bad alternator?
Check the alternator! It has a direct feed and depends on a series of diodes to keep voltage from draining from the battery when the car is off. There are a total of 11 diodes inside of this particular alternator. This is a great case study of a bad diode rectifier. Here is a link to a diagram for this particular alternator.
What should I do if my car battery keeps draining?
Get a multimeter that can measure Amps, and with everything turned off in the car, disconnect one off the battery terminals, then use the multimeter in current measuring mode to reconnect the circuit and look for a current flow. If everything is OK, there should be nothing, but if you have a leakage you will see current where there should be none.
How is parasitic drain caused by alternator diodes?
Parasitic Drain Caused by Alternator Diodes: the Battery Goes Dead… The battery goes dead if the car is not started every three days. I understand that it could be the alternator diodes. If I disconnect the alternator lead to the battery will this stop the drain?
How to fix a parasitic drain on the battery?
A failed diode in the alternator creates a closed circuit that drains your battery even when the engine is off. If you’re too busy during the workweek and can’t get to it until you’re off, some short term fixes are to disconnect the battery at night, and carry a portable jump starter in your vehicle.
Can a bad alternator drain a car battery?
A car alternator recharges the battery and powers certain electrical systems like lights, radio, air-conditioning, and automatic windows. If your alternator has a bad diode, your battery can drain. The bad alternator diode can cause the circuit to charge even when the engine is shut off, and you end up in the morning with a car that won’t start.
How to fix a parasitic drain on a multimeter?
Disconnect the negative battery cable. On the amperage side of the multimeter dial, set it to 20 amps. Disconnect the negative battery cable. Touch a lead to the negative battery cable terminal. Touch the other lead to the negative battery post, completing the circuit within the multimeter, which will display the amp draw.
