After a short trip across the San Mateo Bridge from Burlingame to Union City (15 miles), I came to a stoplight and then it happened. The ICE started then 2 seconds later it shut off. 2 seconds later on again then off, then on and off again until the light changed and off I went. This on/off interval cycled maybe 6 times or more before I accelerated. By the time I got to my destination, all was well again. I shut it down, waited, started it, no problem. Start, wait, shut down - all is good again. Any ideas what that was about? I hasn't happened again since. Thanks. olcorral.
Don't worry. It's normal operation (I'm almost positive). If the Prius determines that your battery has been charged beyond capacity (and you are standing still) it will actually spin the ICE using the extra battery charge. It will continue to cycle like this until the extra charge is gone (or you start driving). It doesn't use any gasoline doing this and the ICE is never started (as can be seen from the display). I'm amazed how many ways the Prius is smart.... It keeps coming up with new cool solutions!
Yeah, I noticed it last night too. It was about 35F degrees. I thought maybe it had to do with the temp. or that I had the heat on full blast. I had been driving for ten minutes and it did eventually stop after a couple of minutes,. I still have no idea why it happened and if it is normal.
This is completely normal. Your battery had a little too much charge in it, so it used some power starting the engine to bleed it off. I've had this happen to me going down a 3 mile stretch of slight downhill with a ferry at the end. Your battery never knows if you'r about to go down a hill, so it always leaves a little bit of head room for charging in the event that you do. If it gets too close to full, it will cycle your ICE to (unfortunatly) waste a tiny bit of energy. Here is an interesting time to realize that your car doesn't have a starter motor. It just uses the main motor to get the engine started.
