Prius battery life

Friends of mine are looking at an '04 Prius. It’s got low miles but back when I was considering buying one I remember the great panic of 5 year battery warranties and $8,000 replacement costs. AFAIK the battery apocalypse didn’t happen, but surely a 12 year old NiMH (right?) battery has either already been replaced, or is due. What’s the straight dope on old Prius batteries?

My last Prius was a 2005, and I put almost a quarter of a million miles on it before I wrecked it. My current Prius is a 2005 with… I don’t know, 175K on it? No issues with the batteries on either car (touch wood).

by all accounts the Prius’s battery has far outlived what people expected.

plus, NiMH cells don’t “age” as rapidly as lithium cells.

Mine is a 2011, with no issues. But I only have 17,000 miles on it, so there’s that. Selling it this year, though.

When is it due? Is it a time or mileage recommendation?

I still drive my '05 Prius with 160K miles and original battery and haven’t noticed any degradation at all.

Mileage seems like a bad metric, as 250,000 highway miles would barely use the battery, whereas 100,000 city miles would use it constantly. Age seems like it would be a bigger factor. I was hoping there’d be a consensus forming about what age we should start factoring in a $3000 replacement cost into the purchase price of a used Prius.

eta: Degradation doesn’t seem to be an issue either, as (what I’m reading) the battery either works, or it lights up the dash like a christmas tree.

I’m happy to be corrected if wrong, but I don’t believe there is a known battery life for the Prius hybrid battery. My owners manual doesn’t mention replacing it in any of the service cycles and I’ve never heard any fellow owners say it was “time” to replace their battery.

The Prius Synergy hybrid system is a very fine piece of engineering. It automatically keeps the battery in the ideal ranges of charge to maintain whatever it’s battery life is. Meaning that it never is allowed to drain completely (as long as there is gas in the tank) and it’s never charged beyond it’s healthy maximum.

Mine is a 2007 and I adore it. I usually get a new car when the current one is over 7 years old but this one isn’t even starting to feel old.

When the battery shows signs of age, the most likely symptom will be decreased capacity. FWIW, my Mitsubishi i-Miev has an 8-year 96000-mile battery warranty which specifies that the battery can lose up to 10% of its capacity and that’s considered normal aging and not a failure. I wouldn’t be surprised if you found that a battery pack could go three times its warranty and still have at least 50% capacity.

Remember that, with any vehicle, there’s always a chance that you’ll need a major overhaul (like a new engine?) which could run several thousand dollars. The same goes for EV battery packs. Que sera, sera.

And in the case of hybrids, both. :eek:

The Prius Batterypocalypse that everybody was screaming about in the early 2000’s never came to pass. I was interested in buying a Prius back then but held off to see if they’d all fail or not (remember the first model year in the USA was the 2001, and they were estimating a 7 year battery life, so if the Chicken Littles were right, we’d have had mass failures starting in 2007). They didn’t, so I bought. Nine years later, mine is still going strong!

But surely there’s going to be a battarypocalypse at some point, right? Can’t fight entropy and all that. Right? RIGHT?

I just don’t want to tell these people, “Sure, buy a Prius, the batteries never die!” And then 13 years ends up being the Year That Chemistry Wins.

Mine is a 2010 with 65,000 miles of Bay Area city and freeway rush hour driving, which is probably worst case. So far it is fine, though the capacity might be down - but I seldom drive it long enough to fully charge the battery.
Around the Bay which is ass deep in Priuses I think we’d have heard of a problem if there was one.

I would think someone has done a study of the real-world life span of the batteries by now. I’m sure Toyota has and has kept it proprietary, but hopefully someone has done one for public consumption?

Since I don’t have such a thing at hand, I’ll chime in with more anecdata that my 06 Prius just rolled over 200K miles and hasn’t had any issues. Granted, I haven’t kept track of the mileage for several years. If the battery has been slowly losing capacity and requiring the gas engine to work more, I wouldn’t know it. But at least I haven’t noticed any dip in mileage.

ETA: the miles on the Prius were mainly in-town miles for the first few years, then a LOT of long distance highway miles for a couple years, then back to almost all in-town miles.

I keep a spreadsheet. I bought this car in September, 2013. The current average is 44.1 mpg. I generally cruise 0-10 mph over the speed limit.

That’s about what I was getting when I stopped keeping track several years ago. I don’t know what it is today. My wife drives it every day now.

Now, I had an '05 that I tracked religiously before I crashed it in '06. For that year, my average was just over 50 mpg. I want to say 50.3 or 50.4. That was pretty cool. After the crash, I changed jobs, so I no longer had the benefit of whatever accident of topography and traffic allowed me to get such good mileage on that commute.

IIRC, the warranty from Toyota is for 10 years or 150k miles. As with many things, you can push that and in some cases you’ll get someone to go a long way beyond that (car companies don’t set the warranty to expire the mile after you cross over…but then, they set it that way because some non-zero number of issues will start emerging at that point). You could probably get the battery tested if it’s a concern. Or test drive it and see if it’s getting close to what it’s supposed to wrt gas mileage (and see if the gas engine is running a lot more than it should).

I’m not sure what the replacement cost actually is for a new battery, but check to see the status of the warranty and what the used car dealer or whatever is giving you as well (and if there is an extended warranty available).

My parents had an '04 Prius, which has now passed on to my brother. I don’t know how many miles are on it, but I would guess at this point it’s closing in on 200K. So far there have been no issues with the battery, AFAIK.

I don’t get it. Surely it used the battery for many segments on the highway trips ??
Or do you mean that after the first segment, the battery is effectively flat and the car runs off the petroleum engine only ?

Anyway the idea is that the batteries are lasting well, and you can replace individual cells if there a random failure occurs. There are people who will test out the battery pack for good and bad cells…

The hybrid batteries seem to be lasting longer than the car, on average. There have been the occasional battery failure, but not mass, simultaneous failures of all cars in a single model year. The occasional failures seem to be related to manufacturing defects or other oddities. See Priuschat internet forum for more details on that.

I still occasionally see a First Gen (model year 2001 - 2003) car on the road in my area.

Another thing to note, but more just trivia:

Prius actually has two batteries. The hybrid battery which is what powers the drive train, and an accessory battery that powers lights, radio, wipers, etc. If you accidentally drain “the battery” by leaving your lights on for example (I’ve done this twice when my tall dogs turned on the dome lights without me noticing), that’s just the accessory battery. You can jump the car to get it started, and when you do that, you’re just jumping the accessory battery. After that, you need to drive for about 20 minutes so that the hybrid battery has time to recharge the accessory battery.

The battery of a hybrid is mainly depleted during acceleration, and recharged during deceleration. This happens a lot during “stop and go” traffic. Cruising at a constant speed may not use the battery at all. This constitutes a large fraction of highway driving. This explains why the Prius actually has a better EPA rating for city than highway, the reverse of what you see on most ICE cars.

EVs also are more efficient in city driving, because the major source of lost energy is wind resistance rather than internal mechanical losses to keep the engine spinning.