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Prius fuel economy is nearly as efficient a decade and 206K later
Prius batteries hold up pretty well afterall

One of the big questions that consumers have when shopping for a hybrid on the new or used car market is “How long will the batteries last”. That question is the one that at times keeps people previously interested in a hybrid from buying due to the thought of an expensive battery replacement years down the road.

Consumer Reports Car Blog has answered the question of how well a used Prius performs recently. The blog got its hands on a 2002 Prius that has 206,000 miles on the clock, put the car on the test instruments, and pitted it against a 2001 Prius that they tested back when the car was new with 2,000 miles on the clock.

The results are very impressive. The 206,000-mile Prius performed nearly identically to the 2001 Prius. When the editors tested the 2001 Prius with 2,000 miles on the odometer, it racked up highway mpg of 48.6 and city mpg of 30.5. The 206,000-mile 2002 Prius on the same instruments coughed up 46.3 mpg on the highway and 32.1 mpg in the city. This brought the overall combined fuel economy number to 40.4 mpg compared to the new 2001 Prius combined rating of 40.6 mpg.

The 2002 Prius with 206,000 miles on the clock is also reportedly still on the original battery, engine, and transmission. The performance tests show that the car is just almost exactly dead on with the performance when new despite all the miles driven.

The editors at Consumer Reports note that replacement costs for the Prius battery could be as much as $2,600. However, they point out that a Prius owner could likely get a unit from a junkyard for about $500.

Toyota unveiled the latest hybrid called the Prius V back in January.



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RE: Fairly Impressive
By lightfoot on 2/17/2011 12:55:22 PM , Rating: 5
This study suffers from selection bias - this single car has an original battery and is still in driving order. The question is how many Prius are not still in driving order and how many of those were due to battery failure.

quote:
The 2002 Prius with 206,000 miles on the clock is also reportedly still on the original battery, engine, and transmission.

The article lists three components that were original, but does not list any repairs or the cost of the repairs that were necessary. What about the alternator? The electric motors? The regenerative braking system? My parents 2001 Prius has had many issues, including the need to have the battery reconditioned. Finding a single unit in good running order does not mean that the entire fleet can be expected to do as well.

Ideally you would want to investigate a sample units (at least 100) and determine what percentage of those have failed or have required major repairs.

I know of a 1973 Fiat 300 Special (with the original engine and transmission) that is still in working order. That doesn't mean that those were good reliable cars.


RE: Fairly Impressive
By MrTeal on 2/17/2011 1:04:46 PM , Rating: 2
Of course, but that goes without saying for any car. How many cars have you owned to 200k miles that haven't needed things like an alternator or water pump replaced at some point? One of the big early knocks against was that you'd have to replace the batteries early in their life at a huge cost. While this doesn't show that the average lifetime is 200k, it shows at least that some are capable of meeting and exceeding Toyota's claim that the battery will last the life of the car, which Toyota defines as 180k miles.

I'm not a fan of hybrid's by any stretch of the imagination, but at least this is some good news. Way better than Honda updating the car's firmware to lower the fuel economy in order to cover up faulty/undersized batteries.


RE: Fairly Impressive
By lightfoot on 2/17/2011 1:32:13 PM , Rating: 2
My only point is that you could take two identical 2002 Prius with 206,000 miles on them and get very different results. One could have had the vast majority of its milage put on through highway driving, and the other could have been mostly city driving. The difference being that the highway milage would have significantly less load placed on the batteries and thus would last longer. The very fact that the car is still operable and has original equipment may make the unit an exception case, not an average case. The only way to tell would be with a much larger sample. With a sample size of one, this is an anecdote, not a study. Regardless of what tests were done.


RE: Fairly Impressive
By ChronoReverse on 2/17/2011 2:07:03 PM , Rating: 1
Yes. However, we do have a lot more anecdotal evidence from various sources. For instance, the taxi fleet in Vancouver has been using Priuses for a while and have put in similar or greater numbers without issue.

http://www.autospies.com/news/Prius-taxi-paid-for-...


RE: Fairly Impressive
By therealnickdanger on 2/17/2011 3:56:17 PM , Rating: 3
It should be noted that this article is simply describing the results of a single, simple before/after comparison, so arguing about anecdotes versus studies is moot. This wasn't a study and never professed to be a study. I wanted to point that out before the discussion devolves further.

:)


RE: Fairly Impressive
By chick0n on 2/17/2011 1:32:11 PM , Rating: 3
Which car does not need maintenance ?

why just mocking Prius?

which car has 200K on the odo does not require basic stuff like water pumps, alternator, timing belt, etc etc at least ONCE ?

if the car has 200K miles and it still get the same amount of mpg as an almost brand new one I would say that is pretty impressive.


RE: Fairly Impressive
By lightfoot on 2/17/2011 1:43:50 PM , Rating: 2
The point is that you could take ANY car and pick a single unit to test and get the same results. This is not specific to the 2002 Prius.

I'm sure you could find a 1965 Corvette that runs better today than it did when it was new too, that doesn't mean that the majority of 1965 Corvettes run better than they originally did.

Now if they said that 50% or Priuses run within 90% of their original specs that would really be saying something. Saying that ONE Prius, even a randomly chosen one, (which this one wasn't) wouldn't be saying much.

Simply picking a running Prius with an original battery pack may easily put this in the top 10% of Priuses. Or it may simply be average. The problem is we simply don't know because the study didn't attempt to find out.


RE: Fairly Impressive
By Jedi2155 on 2/17/2011 4:19:23 PM , Rating: 2
I"m willing to bet that more than 50% of Priuses run within 90% of their original specifications as those NiMH battery packs are extremely durable especially with the load profile they put on those packs even in city driving conditions.


RE: Fairly Impressive
By walk2k on 2/17/2011 4:19:57 PM , Rating: 3
And you put a lot of research into it huh?

309k prius - http://www.cleanmpg.com/forums/my-ride/t-ride-5719...

32 prius taxis in canada some with over 300k miles - http://www.motorauthority.com/blog/1023454_toyota-...

prius taxis in Denver with over 200k - http://www.allaboutprius.com/blog/1019563_toyota-p...

You can't even be bothered to do a simple google search yet you question the methods of the reporter? good job failing.


RE: Fairly Impressive
By chick0n on 2/17/2011 4:25:30 PM , Rating: 3
People can't even google these days ... thats just sad.


RE: Fairly Impressive
By Just Tom on 2/19/2011 2:09:38 PM , Rating: 2
His point is valid. A single instance is meaningless.

It is impossible to draw any conclusions from any of your links. One of them was the self report of an enthusiast. The other two were taxi fleets. All they might signify is that Priuses work well as taxis. What is needed is analyses of cars driven under more typical driving conditions.
What I’d like to see is leased Priuses tested at the end of their leases. That data would be interesting.


RE: Fairly Impressive
By YashBudini on 2/17/2011 7:51:56 PM , Rating: 2
quote:
which car has 200K on the odo does not require basic stuff like water pumps, alternator, timing belt, etc etc at least ONCE ?

@ 265K
Original
Alternator
Water pump
Spark plug wires
power steering hoses
radiator hoses
front brake calipers
Transmission
Headlights
Muffler
Fuses
engine

Timing belt - 4th
Battery - 3rd
Steering rack - 2nd
Radiator - 2nd
Rear calipers - 2nd
Struts - 2nd
Radio - 2nd (panasonic died after 13 months
Sony in car almost 14 years.)
Cat & Y pipe - 2nd
O2 sensors (3) - 2nd
Tie rods - 1 replacement, other original
Fuel filter - 2nd
Sway bar links: 3rd
Drivers seat belt tensioner - 2nd
Transmission services: Appx 6
Spark plugs: 4th (Denso sucks)

brake pads
front - 3 or 4
rear - 4 or 5
(highway miles)

# times towed - 0
# miles on the spare - 0
Check engine light - off


RE: Fairly Impressive
By Solandri on 2/17/2011 4:00:09 PM , Rating: 4
quote:
This study suffers from selection bias - this single car has an original battery and is still in driving order. The question is how many Prius are not still in driving order and how many of those were due to battery failure.

It doesn't suffer from selection bias. If you use their test to draw a conclusion about the longevity of Prius batteries, then yes it suffers from selection bias. But that's not what Consumer Reports was doing.

Consumer Reports was approaching this from the perspective of the used car buyer. They were trying to answer the question: The Prius' battery is rated for about 10 years. If I buy a 10-year old used Prius, should I expect the battery to function substantially worse than when new? So they bought one that fit the criteria and tested it.

The case you cite, of Priuses which are not in driving order because of a failed battery, doesn't enter into the equation from Consumer Reports' perspective. A Prius like that would not be for sale to a used car buyer, and hence is a non-factor.

Take the test for what it is. Don't try to read too much into it. All it says is that a drivable 9-year old Prius has a battery which is nearly as good as a new one. It says nothing about the longevity or failure rate of the battery. It only says something about the operating characteristics of the battery if it survives that long.


RE: Fairly Impressive
By lightfoot on 2/17/2011 4:17:15 PM , Rating: 2
quote:
They were trying to answer the question: The Prius' battery is rated for about 10 years. If I buy a 10-year old used Prius, should I expect the battery to function substantially worse than when new?

But they didn't answer that question. They answered "if I buy this specific 10-year old used Prius will it function better than some other brand new Prius that was tested 10 years ago.

The problem is that the methodology used proves nothing.


RE: Fairly Impressive
By Solandri on 2/17/2011 5:04:38 PM , Rating: 2
quote:
The problem is that the methodology used proves nothing.

Statistical sampling is a pretty well-established field. While a sample of 1 is very thin, it does not prove "nothing". It proves that a Prius battery can survive this long with little degradation. And it shifts the burden of proof onto those claiming Prius batteries won't last this long without significant degradation (I was one of them - given my experience with laptop and rechargeable AA batteries, I thought no way it could last this long).

Except for their surveys, which they fully acknowledge are self-selected surveys, Consumer Reports is pretty good about randomizing the samples they get. They don't accept samples from manufacturers for testing. They buy everything they test by going to the store like you and I do. For cars, they pose as regular buyers to insure the car they're getting isn't selected by the dealer as a "good sample", or that manufacturers are posing as used car sellers to try to trick CR into buying from them. Is it possible that this battery was a fluke? Of course it is. But it's more likely that this is a representative sample, because by definition flukes are rare.


RE: Fairly Impressive
By lightfoot on 2/17/2011 6:07:14 PM , Rating: 1
Taking a single sample of a new vehicle from a dealership is very different than purchasing a single sample of a used vehicle from the used car market.

For all intents and purposes every new vehicle off a manufacturing line should be virtually identical. The same can not be said of used vehicles that have over 200,000 miles. They in fact will be vastly different. The same technique therefore can not be used.

Just because a single vehicle tested good after 200,000 miles does not mean that all the vehicles will test good. It does not even mean that most will test good. It proves only that one did test good and, in theory, others could as well.

They have proven that the failure rate is not 100%, not the inverse.


RE: Fairly Impressive
By SlyNine on 2/18/2011 10:03:07 AM , Rating: 2
They are not trying to prove "Just because a single vehicle tested good after 200,000 miles does not mean that all the vehicles will test good"

They are trying to find out if a battery "CAN"<-- key work, meet Toyotas' claims. Indeed they found out, yes it "can". They made no claims to % or statistics. The artical is very much valid.


RE: Fairly Impressive
By lightfoot on 2/18/2011 2:49:25 PM , Rating: 1
quote:
One of the big questions that consumers have when shopping for a hybrid on the new or used car market is “How long will the batteries last”. That question is the one that at times keeps people previously interested in a hybrid from buying due to the thought of an expensive battery replacement years down the road.

I repeat: " How long will the batteries last? "

This question suggests a Mean Time Between Failures (MTBF) type analysis and would require at minimum testing at least two vehicles until one or more failed.

Consumer Reports did not do this. Others have done such tests (as were previously linked above) but Consumer Reports, in this article, did not.


RE: Fairly Impressive
By phryguy on 2/18/2011 3:54:12 AM , Rating: 2
This is old news. DailyTech is more than a month late. See http://green.autoblog.com/2011/01/07/consumer-repo... which linked to http://www.consumerreports.org/cro/magazine-archiv...

Since some are poo-pooing the Prius, see http://www.ctvbc.ctv.ca/servlet/an/local/CTVNews/2... One of their Priuses has over 1 million km (621K miles) and didn't need a new HV battery until 700K km (434K miles).

The electric motors (motor generator 1 and 2) are integrated into the transaxle (power split device). They can fail. Prius has no alternator (nor a starter). I don't recall about the 1st gen (01-03 Prius) but 04 and beyond have no timing belt and use a timing chain.

One can also look at http://avt.inl.gov/hev.shtml and see maintenance histories of Toyota hybrids including Priuses, many of which have been taken to 160K miles.


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