I have a brand new alternator and battery, but it just won't keep the battery charged. It's hooked up right, and it's making me mad cause I thought I fixed it but I guess not, anybody know what could be the cause of that?
What is the charging voltage at 1500 rpm? Should be between 13.8 and 14.2 volts. If that is OK - your new battery might have a bad cell. If lower than 13.8, you have issues with the voltage regulator, alternator, or wiring for those 2 items. Test the voltage and post back.
Do you know if there is a short that is drawing on the battery? Check the draw buy disconnecting + cable and use a multimeter between cable and post. Is the Regulator good? Jump start car and see what voltage and amperage is being put to the battery. You can check Alternator buy starting car and removing cable from battery, see if it will keep running on just Alternator output. If not have it checked, could be defective. If you can, do a draw down test on battery to see how fast and well it recovers, it may be bad. even new stuff can be defective. Good luck.
It might be the voltage regulator, gotta wait til my roommate gets home so i can ask where his testers at
Post #7 here ( http://mmb.maverick.to/showthread.php?t=70738 )by PaulS helped me figure out my Alt was bad. I replaced the regulator also with a solid state. Was like $12.
If I take off either connection to the battery it dies... Good thing I got a lifetime warranty on my alternator. Ima check all that other stuff too.
Disconnecting the alternator with your engine running is not a test for an alternator. They used to test generators that way but all it does with an alternator is spike the voltage to over 90 volts. It can ruin the alternator, regulator and most electronics in your car. There are specific tests that you can, and should, run to diagnose charging problems.