Altrnator Help Please
Thread Starter
Instructor
Joined: Jan 2008
Posts: 149
Likes: 8
From: Scarborough Qld
Altrnator Help Please
Thanks for taking the time to read this.
I am having trouble with my alternator. It doesn’t appear to be charging, or the charge is not getting to the battery. Battery goes flat when parked for the week.
So far I have tested:
1. The voltage at the battery. 12.7 volts at idle. With lights on & revs up to 2500. 12.3 volts. Putting more load on the battery by switching on everything I can find. 12.2 volts.
2. The voltage across A & B, with ignition off, 12.7 volts. With Engine running 12.7 volts.
I then disconnected the red wire at B & tested the alternator at idle. 18 volts. Put the red wire back on & it went back to 12.7 volts.
Can anyone answer the following Please?
Should there be voltage running to the alternator at B when the ignition is off?
Why is the voltage different at B when the red wire is disconnected (at idle)?
What do the wires at C & D do???
Thanks in advance for your help.
Happy New Year
I am having trouble with my alternator. It doesn’t appear to be charging, or the charge is not getting to the battery. Battery goes flat when parked for the week.
So far I have tested:
1. The voltage at the battery. 12.7 volts at idle. With lights on & revs up to 2500. 12.3 volts. Putting more load on the battery by switching on everything I can find. 12.2 volts.
2. The voltage across A & B, with ignition off, 12.7 volts. With Engine running 12.7 volts.
I then disconnected the red wire at B & tested the alternator at idle. 18 volts. Put the red wire back on & it went back to 12.7 volts.
Can anyone answer the following Please?
Should there be voltage running to the alternator at B when the ignition is off?
Why is the voltage different at B when the red wire is disconnected (at idle)?
What do the wires at C & D do???
Thanks in advance for your help.
Happy New Year
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
Can't help you with all the voltage comparisions but I picked up a Solar battery and charging system tester for $70.00 after attending a C5 tech session at Carlisle. Tester will isolate a test for battery health from the charging system and than permit a test to determine if charging system is generating voltage to restore battery use.
Melting Slicks
Joined: Mar 2008
Posts: 2,023
Likes: 6
From: Austin Tx
Are you sure that you don't have a battery drain? There are a number of common causes.
Have you tried disconnecting the battery while it sits?
After the battery has died, and you've jumped the battery, what is the reading on the ammeter? Is it on the + side? How far, and does it go back down to 0?
Have you tried disconnecting the battery while it sits?
After the battery has died, and you've jumped the battery, what is the reading on the ammeter? Is it on the + side? How far, and does it go back down to 0?
