Like many articles, this one started with a reader question. Casey Krakowiecki wrote:

I'm interested in buying a new Toyota Prius hybrid. I hope you can answer a couple of questions that will help me.

(1) Are the rechargable batteries guaranteed for 8 years? If they fail at 7 years and 11 months, do you get them replaced free of charge, or are they prorated?

(2) What happens to the resale value of a Prius if you want to keep it for six or seven years, knowing the cost of replacing batteries is $3,000?

They're both good questions.

2011 Toyota Prius

2011 Toyota Prius

To answer the first one, John Hanson, Toyota's National Manager, Environmental, Safety & Quality Communications, responds:

"The battery pack in any hybrid Toyota is warranted either for 10 years or 150,000 miles (in states with California emissions laws) or 8 years or 100,000 miles in all other states."

And, he adds, "There's no pro-rating at all. The battery will be replaced at no cost if necessary during the warranty period."

As for the effect on used Prius prices, there doesn't appear to be a discount for older Priuses based on concerns about the life of the rechargeable battery pack.

Indeed, Toyota says the battery pack is one of the least-frequently replaced items across all Prius models. And some proportion of the packs it has to replace haven't failed, but were damaged in collisions or other accidents.

2004-2009 Toyota Prius battery pack, second generation

2004-2009 Toyota Prius battery pack, second generation

The cost of the pack varies with the year of the Prius. Replacement batteries for the 2001-2003 Prius cost $2,299, and those for the more common 2004-2009 model currently run $2,588.

Labor costs could total several hundred more dollars if you have to replace the pack, for whatever reason.

One knowledgeable Prius owner suggests purchasing a spare used battery pack, an idea we think is interesting--but definitely overkill for all but the most mechanically-minded owners.

A Toyota Prius battery, by the way, contains 168 1.2-Volt nickel-metal-hydride cells, which contain a total of 1.6 kilowatt-hours of energy. Its peak power output is 27 kilowatts, or about 36 horsepower.

For more information about the nickel-metal-hydride battery pack in the 2010 Toyota Prius, see "30 Days Of the 2010 Toyota Prius: Day 12, Battery Pack".


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