Had the alternator checked. It's good. Belt is on tight. Replaced the Voltage regulator. Jump starting the engine off my truck.... starts right up. At the battery, it shows just under 12V and falls slowly. Same with my volt meter. I shut it down around 8-9V.:af: What Am I missing?
How old is the battery, Is it maintence free? I was having that problem with the battery in the Queen Mary III, battery only had like 150 cranking amps. Replaced it and everything is fine.
So...the battery being low or bad could cause the system to not charge? Isn't an alternator suppose to take over once things are started?
Also....forgot to mention... once the system shoots down to around 8 and I shut it off.....I still get an 11.8 reading on the battery. Does the battery just need to be fully charged/swapped?
Simple test, start the car and disconnect the battery, if it stays running, you know that the alternator is working.
More than likely, you have a problem in your charging system. You need to check the voltage out of the alternator, and also out of the external regulator. Post back what you have. Should have good voltage from the alternator and about 14.6 out of the regulator, and to the battery. If the alternator output is good and your regulator is good, then you must have some wiring issues to track down. I don't think you have a battery problem. Good luck.
NEVER disconnect the battery while the engine is running. This is not a test. It will most likely spike the alt. and destroy it. This is a old shade tree test that is wrong. never have I seen in any books or taught in and school that test described. The CORRECT test is to use a voltmeter.
New battery is in. Testing at the back of the alternator shows right around 12V at idle. Re-ran the alternator's ground directly to the battery. We'll see what happens I guess.......o No:
The alternator is toast. A fully charged battery will show 12.6 volts. 11.8 is discharged. If the alternator is charging, you will see 13.8 volts minimum across the battery with the engine running. It should be 14 volts or more.
My buddy suggested I try the field thing. Run a jumper from "F" on the alt to the battery post on the alt to see if that jumps voltages up where they need to be. He thinks it may have de-magnetized itself.
Worth a shot. But if you discover the alternator is bad, take this opportunity to switch over to an internally regulated alternator. have Jamie make one for you. He can even supply the wiring harness to convert to the much better alternator. It's very easy to do. http://www.v8buick.com/showthread.php?t=89861 http://www.buickperformance.com/alternat.htm
An alternator can not be demagnetized. The alternating current output of an alternator precludes magnetization. That applies to generators only. Also, full-fielding will drive the alternator to it's maximum output capability. If it's a 100 Amp, that's what it will put out. The voltage can go into the high teens. Try not to have too many accessories running when you do this, and don't do it for long. Also, as Larry pointed out, 12.6 Volts is charged. Even 12.5 Volts represents a fair state of discharge.
If you are trying to run 2 fans off a stock alternator, I'd say it isn't doing you any good. Shutting the fans off, does the voltage go above 13.8? If not, you still have a charging problem.
