When did you have to replace the Hybrid Battery?

I really think that's the key if you buy a higher mileage, older Prius.

Knowing that the Hybrid Battery does have a finite life span, and IF you buy the vehicle, being ready and capable of affording the replacement IF it should happen.

 

I replaced the HV Traction Battery in my 2006 Prius on 11/22/2011 @ 92,600 miles. There was nothing wrong with the battery, but I had an opportunity to swap it out with one from a newer 2008 Prius for $625. I did see a slight 1 - 2 mpg improvement with the replacement battery. My 2006 Prius now has 145,000 miles on it. I avg 43.1 mpg per the MFD display.

 

I recently bought an 05 with 100k on it. It had just had the HV battery replaced at 99k due to failure. The previous owner drove it all the time but had a hill/small mountain to climb and descend everyday. I think that may contribute to earlier, as in 100k, 9 year, lifespan vs. other cars that don't have a higher taxing drive such as those on long straight highway commutes. The previous owner drove the car just like a regular car without any real regard to maximizing the mpg or other prius features, so even with "normal" use it lasted a good while.

 

Thanks for letting me know. This is something I expected. Also, the electrical system warning light just came on. On to the dealership I go tomorrow at Naperville Toyota.

 

The winter drop in MPG might appear drastic, but literally every car suffers dramatic drops during winter. Where some standard cars might even get as little as 15 MPG or even less, at least the Prius II will give around 40 MPG - no less than 35 for sure. No matter how you look at it, Prii reduce our fuel costs substantially. Example: my old Mazda MX-3 1.6 gave me 180 miles out of 45 litres of fuel in cold UK winter months. The Prius gives me over 450 miles for the same amount of fuel in winter. It's a winner!