My battery light is on my 2005 Honda Accord don't know why

How did u test alternator? Did voltage fluctuate when tested. Do your lights brighten and dim when you accelerate. Could be voltage regulator within alternator.

I got my battery and alternator tested at the O'Reillys auto parts store. I had my alternator changed about 5months ago it showed no signs that it was giving out,the battery light wasnt on that time. But I do believe after they put alternator iin the next day the battery light came on.could the alternator be reading on their tester that its working but alternatorin reality be bad?

@Mikbek I don't drive at night but I test drove it and the lights do seem to brighten and dim how do I check the voltage regulator?