I have been looking around for this information, but there's no real specific answers for my situation. Our department vehicle has ~35,400 miles on it since we bought it new. First gen 2003 Prius. Tons of people are saying the battery lasts forever, but they always cite mileage as the proof. What about age? Batteries can degrade over time, and our car gets very light use. Does anyone have any information that could help us decide what we should do with our vehicle? EDIT: Also, the use is generally short ~1 mile trips around a hilly campus two or three times a day. Hardly any freeway miles. Current budget situations are requiring us to determine whether or not the Prius will survive with minimal maintenance for another 3-5 years. However, our battery warranty is up in just over one month. Help!
In my humble opinion I would keep the car as a new battery is no longer as pricey as they used to be. You can get a replacement for around 2k depending whether you get a new or 2nd gen. reman battery. If the battery goes bad you always have the option at that point to either replace the car or the battery. I do not know the answer to your question so I can only offer my opinion,,,sorry.
It really depends on your flexibility to have repairs made. It all repairs must be made by a dealer, then the battery replacement will be expensive. But, if you have the freedom to have someone in the e.g. physics or electrical engineering department take a look in case of a problem, you could have a repair done for free. Prius battery repair is a junior/senior undergraduate level kind of project. Physics especially may be on the lookout for practical projects to throw at undergrads. Over the next 5 years, I suspect you would more likely have a corrosion problem if anything, than actual cells dying.
Are you talking about the 12v battery (like in all cars, powers electronics when car not totally on, etc.) or your main traction battery? If you've never changed the 12v battery, sounds like it might be time, that could have a big effect on mileage. That's a standard "cheap" fix all cars need, so if that's it you might not have much to worry about.
Our problem is that only Prius that have been "rode hard and put away wet" have reached their end of life. (principally Taxis) Since no Prius that is lightly used, such as yours, has reached end of life, we have little to tell you. As a personal opinion, (not a fact) I think that the amount of time the Prius spends READY benefits battery life. When the car is READY, the computers guard and manage the HV battery to prolong it's life. So low speed, short mileage trips may still offer the battery plenty of time to be pampered by the computers. Long periods of non use, (Weeks or months) would put the battery at risk. Again, just my opinion, but I hope that helps. [Edit: the 'Low mileage' is on the odometer, right? Not low gas mileage?]
Replacing a dead traction battery would cost, generously, about $3k. How many replacement cars can you buy for $3k? Exchanging a possible expense of $3k sometime within five years for a certain expense of at least $16k now makes no sense. Keep the car and be happy.
I think that age has more to do with the hybrid battery life than miles. I have a 2001 Prius that I bought in October 2003 with 17,000 miles. The battery had to be replaced in January 2009 at 197,000 miles. My sister-in-law has an identical 2001 Prius that required a battery replacement in September 2009 at 127,000 miles. I ordered my first Prius in September 2000 and the warranty for the hybrid system was 100,000 mile or 10 years. It was wrecked in October 2003. Later Toyota changed the hybrid system warranty to 100,000 miles or 8 years. So, I believe the 2001 - 2003 battery is good for however many miles it gets in 8 years. My Prius currently has almost 224,000 miles.
My 2002 Prius went 124,000 miles on the battery before it had to be replaced. It simply notified on the panel, and it was a crap shoot as to how long it would warn before it went out so i just did it. I had begun to notice going up the grade to the mountains that the car would no longer hold 70, even floored... so they had been getting weaker for some time.
