Rep Power: 0

I just recently purchased a re-built 02 civic lxg. When I bought it around the end of September the abs light would flash on and off, but everything seem to work fine. Last saturday the battery light cam on, but again would only flash and the car seemed to work fine. I thought there must have been a short witht the fuse or something. As well I can not get my cruise control to work. On Tuesday morning I went to go to work and the car would not start as if the battery was dead. That evening I got the car started with a booster pack, but I did not have any of my gagues work on the dash. I tried switching the battery with another one and everything cam back and the abs light was gone, but the battery light was still on unless you reved the car up past 4rpm, but would return if dropped below 2 rpms. I took the car for a ong drive (aprox 45min) to see if I could charge up the battery, the light remainded the same. Near the end of the drive I again lost all of my gagues, radio, ac etc, but the car was still running. After I returned home, I have tried starting the car and it is starting fine and everything is back. This morning I replaced the battery with my old one that has been charged and everything seems to be working finr, except the battery light it still doing the same thing stays on till after rpms have reached above 4 and returnes if rpms drop to 2 or below. Anybody have any suggestions what the problem may be?

 
Rep Power: 813

the battery light indicates a charging system (alternator) failure, NOT a bad battery.