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Battery light flashes on and off

Hello My name is Erin and I am beside myself. I live in Atlanta GA and I have 2010 Honda Odyssey with 130000 miles on it. About two months ago the car wouldn’t drive and was like jumping. When I finally got it to my mechanic he said that my Alternator went bad and blew out some other things. He replaced the parts and the Alternator. The mechanic also recommended that we get a new battery. We got a new battery, but ever since the van has a new Alternator put in the battery light will occasionally flash on and off for about 6 seconds at a time. It did not do this prior to the new parts. So we went back and had the alternator replaced, local mechanic and same mechanic, not Honda dealer, and the battery light is still flashing on and off. My mechanic tests the amps, battery cables and wires and is just stumped. I took the van to another local mechanic and paid another $130.00 to look at the van to find out they are stumped. I am really concerned since I drive my children and we drive to Sarasota to visit family and seeing the battery light on and off is nerve racking and stressful to me. Please help! I can’t afford any more local mechanics.
Thank you,

You may have a fault in the charging system monitoring electronics, but before going down that route, first thing I’d do in this situation is a couple of voltage measurements, at the battery terminals.

  • Before first start of the day, should measure about 12.6 volts.
  • Immediately after first start of the day, should measure in the 13.5-15.5 volt range.

What voltage measurements does your mechanic say they got?

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The first thing I would check, is that the serpentine belt tensioner is putting enough pressure to keep the belt tight enough , and that the belt is not slipping. This would cause the alternator pulley to slip on the belt, thus turning on the battery light, or causing the light to flicker,