About 3 hours into a 4 hour trip up I95, an accident ahead slowed traffic to a very slow crawl. It was stop and go for about a half-hour, during which time I noticed the battery icon gradually fall from 7-out-of-8 blue layers down to 3. Once we got past the accident, the congestion cleared and all the reassuring blue quickly came back. Was that normal Prius behavior? And what if the congestion had lasted longer?
Yes Yes Yes that's normal...that's perfect. That's you not polluting the environment or wasting unnecessary gas while sitting in traffic. That is the beauty of the Prius, it uses the battery at lot demand times instead of the ICE. Rather than worry next time you should sit there smuggly enjoying your quiet fuel saving time in traffic!! You never have to worry about the battery getting too low the computer won't let it happen, if it had gotten any lower the ICE would have kicked on long enough to recharge a bit then shut down again.
I had a similar thing happen on my way from Los Angeles to Laguna a week or so ago. The traffic on the freeway became slow and go for about thirty minutes and my battery was down to the last two bars (my mileage was great - 4 five minute segments over 70 MPG). Then the engine started up and ran for a while, whether I was moving or not and the battery went back up to four bars. Take comfort, it seems that the car knows what to do. (Course my mileage for that segment sucked ... ah well, better than sitting by the side of the road.)
Also, it's been noted elsewhere on here that there's still approximately 20-30% charge left in the battery even if it gets all the way down to no segments - but usually the car (at least mine) wants to charge before that. -m.
It has been my experience (going over the continental divide in Colorado) that the battery display will get down to 2 blue bars and then they will turn pink. Then the ICE will kick in to charge the battery. When it does this the arrows go spastic, it charges for a second & then the arrow reverses to use the charge, then the ICE charges, and then the battery discharges. Of course, all of this was going on while climbing up to Eisenhower Tunnel with grades of 6-7% for miles - all up. The best part was, of course, coming down after having crossed the divide, it was all charge, charge, charge - back up to all green bars!
