charging system fail

[smellmyfinger]

been having a problem with electrical. alternator not charging the battery all the time.changed the battery and alternator. drove for a couple of days and battery gave out. charged battery and tested alternator by disconnecting battery with engine running. engine died. battery cables are good and clean.
is there a ground wire to the alt. how hard is it to change the alt. plug and wire, i followed it to under the fuel rail where does it go.

[Bad_dude]

How do you know it's not charging? Let the car run and put a voltmeter on the battery. If it reads 14.5V or higher than it's charging. Have the battery load test, if that pass then check for parasitic draws. Use the same voltmeter but use the Amp reader to see where the draws is coming from. Use the fuse box to narrow it down to the location.

[oyajicool]

Disconnecting battery to test alternator while engine running is not something you want to do. Doing so may fry sensitive electrical components. Also, alternator needs battery voltage to run properly.

[nine_deuce]

Unhooking the battery while the car is running is an easy way to check if your alternator is bad. If you unhook the battery and the car dies, odds are, the alternator is shot.

Have you checked the fuses? Changing an alternator isn't too hard, there is 1 electrical plug and a ring terminal under a 10mm nut. I'd take it and have it tested, just to be sure. And if it is in fact bad, you already have it off to cover the core charge of a new one (assuming they charge a core there)

[oyajicool]

http://wiki.answers.com/Q/What_will_...ine_is_running

http://www.troubleshooters.com/dont_...ct_battery.htm

http://www.automotiveforums.com/t768...s_running.html

http://www.aa1car.com/library/2002/cm10220.htm

Normal charging voltage should be 13.75 to 14.25 VDC for 12V battery.