Is this true??? (Gen I battery failures.)

Hi Daniel,

The NHW10 Prius sold only in Japan uses D-cell sized batteries strung together in series. Hence the technology is different compared to the rectangular battery modules found in NHW11 (Classic) and NHW20 (2G).

Since you apparently are unaware of Classic traction battery failures, I recommend you enter the Gen 1 Prius Discussion subforum and look for the following string:
http://priuschat.com/forums/generat...-g1-traction-battery-please-tell-us-here.html

Also see my poll that shows 18% Classic traction battery failure rate reported so far.
http://priuschat.com/forums/generation-1-prius-discussion/45766-classic-prius-repairs.html

The 2G traction battery has a better design compared to Classic, but my prediction is that you will see similar failure rates reported after another 3-4 years have elapsed. (I hope that the idea that the battery will eventually fail is not a big surprise to most owners.)

 

You also have to realize that the G1 battery failure data is a VERY small sample of the total number of G1s that were sold.

 

A dose of perspective is needed too. It would truly be a miracle of none of the Prius ever experienced a failure, especially being aware of the abuse owners can (and unfortunately, some do) inflict on their battery-pack. It's the equivalent of expecting a traditional vehicle to never have a transmission failure. That's totally unrealistic. Just look at how many transmission places are available for repair & replacement.

From the computer industry perspective, how many hard-drives that crash still keeps the product within the "will gladly buy it again category"? And exactly how long should the "lifetime" expectation be anyway?

The hope for Prius would be that the number is very, very small and it shrinks for each successive generation.

It totally sucks if you are the unlucky person to experience a failure, but then again the transmission death in my Taurus is what led me to Prius. Life isn't fair. But we're here to try to help if we can.

.

 

As of last year for the current model there were about 11 "infant failures", that is, battery packs that failed within 3-4 years of new. Toyota replaced them all under warranty of course.

The current model battery pack has more differences than just the cylindrical vs "prismatic" design. The internal connectors are larger. The cells are sealed better. There are fewer cells in series, which makes it easier to monitor the pack health and determine when to charge and when not to. According to Toyota, the pack is cooled better as well.

As with anything, lessons were learned and corrections applied.

But as stated above, the current model packs WILL eventually start failing. There are, after all, a lot of cells in series. All it takes is a few of them to fail to cause pack problems. I find it amazing that so few have failed so far! Compare the Prius pack to a cell phone battery, even the older NiMH type. They would last, what, two years? The management system Toyota uses does a very good job protecting the battery from abuse!

 

While the first may be true, as has been noted by others (and 10 years is longer than I would expect it to last), the following paragraph seems a little off. I suppose they may have been talking about a battery for all-electrics, but it doesn't sound consistent with what I've heard about Prius batteries (or what I paid for my Prius!).

And after 10 years, $3K won't make me too unhappy. Who knows, by then I may just trade in my Prius on a nice all-electric myself.

 

so we can acspect the prius battery to last 10+ years

 

Hi David,

What is your source for the above assertion?
Thanks!

 

Those cylindrical cells are also similar to what's used in the
Insight and Civic hybrid, and Honda's been replacing their share
of those gratis as they start going weak. At least in the
Insights, where they basically admitted that the earlier cells
weren't as robust as they should have been.
.
_H*

 

I wonder ... of the people who have replaced gen-1 batteries with new ones from Toyota rather than salvage, has anybody lifted the lid to see whether the current replacements are built with the original-style modules or with the newer ones that were introduced with the gen-2?

-Chap

 

I spent a career in the semiconductor corner of the computer business. For four of those years I was a reliability manager for a major semiconductor factory. None of which makes me an expert on battery chemistry or failure rates, but I'll hazard some guesses.

It seems likely to me that a high proportion of the failures we have seen in the US population so far are a combination of infant mortality arising from undetected manufacturing defects, and unusually rapid natural failure due to particularly harmful use conditions (some combination of high mileage, high-temperature, and an unusually high proportion of charge and discharge to distance).

A classic reliability perspective would teach you that the infant mortality rate contains almost no information about the behavior of the main distribution. Unlike computer chips and even hard disk drives, for traction propulsion batteries it is completely unreasonable to hope that the main distribution does not include very large numbers of failures within the possible lifetime of the vehicle. The electrochemistry going on inside the battery is fundamentally altering its internal state with every ampere hour of charge or discharge. A design so conservative as to avoid main-distribution failure rates of more than a few percent at a million vehicle miles would be much more expensive, and weigh much more, than the one we actually have.

Once we reach the point that five or 10% of a cohort of the first-generation US Prius model have experienced battery failure, we shall begin to have a glimpse of how the main population may be expected to behave. It is not at all obvious to me that the changes between the two US models are likely to have greatly altered the expected battery life. I think the surprise free hypothesis would be that the 2004+ model may see lifetime rather similar to the immediate previous one.

I have not seen distribution statistics for how many miles US passenger vehicles get driven before abandonment these days. Based on casual discussion with friends, I suspect that here in New Mexico the answer is far in excess of 100,000 miles (bodies don't rust here, distances are long, and plenty of people don't mind driving old cars).

When I first quit using nickel cadmium cells for my personal household use and switched to nickel metal hydride, I did not see a single failure in the first couple of years. As my NiCad cells had been failing quite regularly I falsely drew the conclusion that nickel metal hydride was on an utterly different plane of failure free existence. The truth was otherwise, I was just looking at a young population that happened not to have any infant mortality defective parts in it. I continue to like my home nickel metal hydride cell population much better than my old NiCads, but by now I have seen plenty of them fail. Because of increasing production rates, the great majority of the U.S. Prius population is very young.

The relatively low failure numbers reported for the U.S. Prius fleet are a tribute to good quality control that has kept the number of manufacturing defect infant mortality failures low. I celebrate that, but don't mistake it for much prediction of what fraction of this generation will make it past 200,000 vehicle miles without a traction battery failure.

Early Lithium pure electrics and plug-in hybrids are going to have a really tough design tradeoff to make among the variables of battery cost (size), range, and durability. They will find it very costly to restrain themselves so severely as the Prius design did in the way the battery is exercised. I think you can confidently predict some really ugly real-world durability problems in the field experience of the first few years of manufacture of those types. Oddly, the rather good Prius experience to date may hurt them, as it will steal weight from the cautious voices on the development teams.

 

Hi All,

The first generation Prius, in the US had a recal for resealing. One could expect that this was not done, or done poorly in 10% of the cars out there.

I personally do not see a problem with all the packs failing just after 125K miles. That is the design life, and it was still an imature technology (needed sealing recall). Still, people apparently are not aware that their cars will need this work. And this is a bit of a suprise, but really should not be. Old cars are old cars.

Also, if the cars were originally CARB cars, isn't the waranty 150K miles, no matter which state they are in now ?

 

the 1g prius also seems to have less protection against discharge from running out of gas and "limping" to the gas station than the 2g. that happens often enough.

outside warranty, toyota basically does not recharge batteries. this skews the replacement stats, maybe those could have been recharged.

18% is a fine anecdotal number considering that people who have a failure are more likely to seek out a website like PC, but rigorous statistics is based on the concept of random sampling.

 

I believe this sentence is misleading.
The NHW10 battery failure occurs anytime since its launch in 1997, not now.
The NHW10 Prius is a kind of prototype vehicles, therefore Toyota decided it for the Japanese market only and they watches how things are going very carefully.
The battery replacement is free of charge, and owners experienced one or two times replacement.

The NHW11 and later models are completely different story.

Ken@Japan

 

I agree.

39 samples out of 53,009 is only 0.07%.
"Estimated number of Classic Prius sold in the US (launch through Sep 03): 53,009"
http://priuschat.com/forums/prius-hybrid-news/41428-toyota-lexus-hybrid-unit-sales-history-usa.html

Ken@Japan

 

PriusChat has 43,000 members according to the Members List. I had hoped that more Classic owners would respond to my survey.

 

The 10 year/150K mile traction battery warranty applies only to 2G sold, registered, and operated in CA (or other PZEV states).

It does not apply to Classic because Classic Prius was not AT-PZEV certified.

 

Patrick,

Is there a way to do an active member sort (those who have posted or logged on during the duration of the survey) for only the Gen I members (by querying with respect to profile?) This could be expected to provide a more representative estimate. It of course can't account for self-selective sampling--those with problems seeking out the site to inquire, but some members with problems would be expected not to participate as well so there is some small offset. This might help you define the range more fully for skeptics.

I think this is a great service in trying to provide some idea of the battery failure frequency. Even the rates you've reported don't seem excessive and seem reasonable. It is important to distinguish those that failed within warranty from those without. Failing within warranty is good, failing outside of it is not, but would be expected to be the most common mode as the cars age.

I'll also add that if a person has a manual transmission they can expect to change out the friction clutch periodically (my model of Nissan tended to go at 80-100k on the OEM clutch from surveying enthusiast groups/other owners.) Granted, a clutch is cheaper but like the traction battery (or shocks/struts or brakes or tires) it is a wear item. We know they will fail, we just don't have a feel for what is normal.