2006 Prius Hybrid Battery Issues - Possibly End of Life?

Owner of a 2006 Prius, bought brand new August 2006. Current mileage just about 145k. Most driving is city, with some freeway. For the first few years, a lot was freeway since I was commuting far (was averaging 30k/year). It's done long freeway trips too...and lots to Vegas.

Got in the car this morning to go to work and when I started it up, the hybrid battery indicator was at one bar (red). When I parked it yesterday evening, it was definitely higher, at least in the blue and above the halfway mark. I started driving it and it began recharging. When I came to a stop at a stoplight (probably about a 1/2 mile later), the battery was at green (one below fully charged). But then it went to fully charged (still at a complete stop) and the engine turned on. Now I've had this car for awhile, so at times, especially after a long downhill, the battery will go to fully charged and when I come to a stop, the engine will run a bit. But this time, there was no hill, and when the engine turned on, it sounded different.

Anyway, I continued on and the charge came down to normal. About a mile later, as I was driving, I then noticed the charge dropping rapidly. Down to red. This was clearly abnormal, as I was on a level street, and not accelerating fast. So I pulled over into the next parking lot. I parked, shut it off, and then turned it back on. That's when the red exclamation triangle light came on, and the MFD indicated 'Problem.'

I had it towed to the local dealership where they are checking it out now. My guess is the hybrid battery is having issues. Fortunately, I'm just under 145k, and the warranty is 10 years or 150k...so if it is the battery, looks like lucked out there.

Will wait to see what the dealership says, but anyone else have this issue or know what may be wrong?

One more thing. On Saturday morning, upon starting and driving it, whenever I pushed the gas, there was a slight pause before it went forward...kind of like there was no initial power. ICE was on. I parked it that time, turned off, and then back on, and everything seemed to be working fine. But now that I think about it, the engine seemed a lot louder when I was driving it over the weekend.

 

Just got a call from the dealer...yep, the hybrid battery failed. So they're replacing it for free under warranty


Made it just before the 150k warranty expired!

Should I expect better mileage? I was averaging in the 40-43 mpgs lately.

 

I replaced the 12V in April 2012.

 

Picked it up around 5pm this evening. Battery definitely seems better, especially at slower speeds when it only uses the battery. We'll see how the mpg averages out within the next few weeks, when I got it back this evening, it was at a terrible 34 mpgs, got it back to around 36 during the short time I drove it. (I had recently reset it after filling up about 80 miles ago)

And for sure counting myself as very lucky

My dad's Prius (a 2005), lasted around 225k before the hybrid battery died. Quite the mileage difference between his and mine, although his was primarily driven on the freeway in the Seattle area, very little city driving. I'm guessing the city driving, LA freeway type driving, and the hotter weather attributed to mine's shorter life. And I've driven this car...in the desert heat to Vegas countless times, San Diego, up north through the Grapevine, Yosemite this past summer (and packed with as much as it could take)...it's definitely done it's share of hard driving.