A few days ago my discharge warning light (battery light) comes on, but only when I gave it gas in gears 1,2 and 3. Now it is coming on more frequently, but still only when I give it gas and it is in gear. I take it to walmart (only because that is where I purchased the battery in case I need a new one under warranty) and the guy tests it and says the battery and charging system is OK. Still being skeptical I take it down the street to Oreilly's and the guy there says the same thing.

After searching the forum here, I concurred that it could possibly be the brushes in the alternator. For $10 I purchased a brush holder from an auto electric shop last friday and installed it saturday. The discharge light still comes on as it did before.

After sitting for 30 mins or so, the battery puts out around 12.9 - 13v.
The alternator puts out anywhere from 13.8 - 14.2v while running - checking the voltage off the output post on the alternator.

What do you guys think?

 

My girlfriend has an 84 t-bird that does that. When you accelerate the light comes on and when you let off it goes out. Belt is tight and battery never goes dead. All's good except that. lol. Sorry no help but figured I would sympathize with you.
I have a 76 celica gt that I was having probs with. The charge light came on and car died coming home with headlights on. Thought it was the alternator so I replaced it. Now the Charge light stays on all the time. Seems like the charging system is working. I'm only at 12.04 v and dropping very slowly when at idle w/ all lights and heater on. and only 12.4 v but increasing slowly without lights and around 2500-3000 rpm.
P.S.- The connector on the alternator was clipped off so I may have hooked it up wrong but I think its right now. If anyone knows how the wires go please let me know. there is a white and black, a blue, and a green. Plus the big batt wire which is obvious. Any help would be useful. Thanx.

 

Beef I am very curious if you found your solution as I am experiencing the same symptoms. I have a HO alternator giving 14.4-14.8V when it is actually working but it is intermitent and when it isn't charging I am getting the battery light. Brand new Optima red top battery I replaced the day after I replace the alternator. The battery terminals are clean, 120A alt fuse is good, have upgraded "Big 3" in 00Ga wire. Does anyone know why I am only getting and intermitent charge? I wasn't getting this problem before I changed out the battery, but the old battery was toast.