My battery light recently came on in my 2010 honda odyssey. Before this happened it had started making a higher pitched whining sound that goes right along with the engine and the rmps. Not a belt squeal either. It just happened one day. Now the battery light is on and it seems that when I accelerate it charges the battery enough to go forward but ultimately this failed and the car died. I replaced the battery and all seems fine. Minus the noise. Yet the battery light is still on. So I am confused. I am wondering if it is the alternator but the connection between the two is ready just fine.
Check alternator output at the battery at idle and revved up. Should be around 12.5 volts at idle and 14 or so volts when revved. If not, your alternator needs replacing. The whining sound could be alternator bearing going out.
