Reports of my Prius death are premature

Alex Beam silences the death knell for his Generation 1 Prius - The Boston Globe

Thanks to Evan, I helped.

Bob Wilson

 

Nor have any of the other hybrid skeptics. Ignorant, they never figured out there was anything other than a battery in a hybrid. <GRINS>

Ebay: 170517133264
Asking: $449.99, Won $202.49

Actually I volunteered 3% loss per year compounded. The 3% comes from a salvage assocation report of how many vehicles of the USA fleet are turned over to them any given year. Now this is not a linear factor but it is close enough. So 18%/9 years ~=2% straight line. But when you run an annual 3% loss over the remaining Prius each year, ~44,000.

Please don't equate fleet loss rate with battery salvage rate. These are different, entirely different numbers. For example, I have a spare NHW11 battery that I suspect is now self-discharge, useless. There are probably more.

I also suspect there are many more Prius batteries still in the shells in salvage yards. Then there are the fire engulfed Prius. But I also suspect that many salvage yard Prius were just sent to a shredder/crusher and loaded onto an open railroad car and sent to metal foundries. I really have no expectations of salvage yards being in anything but a volume business trying to turnover their inventory.

Bob Wilson

 

I'll try to set up a Google news alert for Alex and "Prius." This is the third story of his that paints the Prius pretty much as I know it to be. It is time to start sharing his skills as a good source. . . . Perhaps include a cover page reference at PriusChat?

Bob Wilson

 

Hi Patrick,

I found another approach different than the 3% fleet loss from the salvage association that gave ~44,000 Classics.

The Department of Transportation has contributed to an EPA emissions model that needs the vehicle age on the road to project vehicle emissions total load called MOBIL6. In their model, they have a table of vehicle populations by age that I can use to project a loss rate, one that is age of vehicle based, for any similar vehicle in that class. The assumption is the NHW11 has similar life-span as their Light Duty Vehicles (passenger cars.):

	Column 1	Column 2	Column 3	Column 4	Column 5	Column 6	Column 7	Column 8
0	Vehicle age	LDV ALL	% of	NHW11 Prius	year	remaining
1	1	0.0706	100.0%
2	2	0.0706	100.0%
3	3	0.0705	99.9%
4	4	0.0703	99.6%
5	5	0.0698	98.9%
6	6	0.0689	97.6%
7	7	0.0676	95.8%	12	129(*)	2003	11	613
8	8	0.0655	92.8%	19	817	2002	18	385
9	9	0.0627	88.8%	15	322	2001	13	607
10	10	0.0588	83.3%	5	562	2000	4	632
11	11	0.0539	76.3%
12	12	0.0458	64.9%
13	13	0.0363	51.4%
14	14	0.0288	40.8%
15	15	0.0228	32.3%
16	16	0.0181	25.6%
17	17	0.0144	20.4%
18	18	0.0114	16.1%
19	19	0.009	12.7%
20	20	0.0072	10.2%
21	21	0.0057	8.1%
22	22	0.0045	6.4%
23	23	0.0036	5.1%
24				52	830		48	237

I used 50% of the 2003 sales for NHW11s sold that year. The calender year 2003 overlaps with the NHW20 introduction. Source: http://www.fhwa.dot.gov/environment/conformity/emission/emismeth8.htm

So given two methods, we get:

• 44,000 NHW11s - using 3% fleet loss per year to salvage
• 48,000 NHW11s - using the MOBIL6 vehicle population by age

Roughly a 10% variation between the two. We can probably improve some of these numbers. Understand that we can't average the two numbers as each is an independent estimate. Rather this gives two, guesstimates and a more accurate vehicle accounting would give a third. The penultimate would be to filter out the NHW11 registrations from the ~250 million vehicle registrations in the USA from all states and territories but you know there comes a point where it is 'close enough.' <GRINS>

For those who are about to ask the obvious question, in about two-four years, the two models converge, ~12 years. Thereafter the DOT model gets pretty grim. The simplest answer is vehicle half-life, 51.4% is ~13 years. Then at ~16 years, 25.6%, half are lost again.

Now there is another fascinating model that could be thrown together to project the inventory of NHW20/ZVW30 battery modules available to keep NHW11 batteries running. But there comes a time when a model built upon an assumption becomes a 'house of cards' that is likely to fall down.

Bob Wilson

ps. It is weird what some of us do for fun.

 

The history of Prius estimated life:

• 109,000 miles, 10 years - CNW Marketing "Dust-to-Dust" report early in 2006. Obscure in his methods and data sources, his reported owner profiles suggest it was heavily weighted to the early, NHW11s and what appeared to be a small sample set, very small. For example, retired and college students were heavily reported. Yet he never lets the college students 'grow up'.
• 3% (2.67%) per year - report by Emilio Brahmst, "Copper in End-of-Life Vehicle Recycling". If we take 66% reduction in the fleet, that would be ~240,000 miles after 16 years. At 50% reduction, 390,000 miles after 26 years. The problem is taking a straight-line vehicle loss per year but with only a cumulative data point, the alternatives were worse.
• Distribution by age for light duty vehicles - Department of Transportation, MOBIL6 model. The 66% point would be 180,000 miles, 12 years. The 50% point would be 195,000 miles, 13 years.

As for the cost of keeping a vehicle operational:

• warranty - typically handling infantile problems, the 3 year, 6 year and 8 year warranties keep the fleet operational
• early repairs - often covered by insurance claims, these also go to the service centers and draw upon manufacturer parts. However, we also see growing skills in independent shops and early do-it-yourself owners. It also includes the 'auction' buyers who fix them up 'good enough' to make a little money (very little.)
• older repairs - are handled from salvage between independent shops and do-it-yourself owners. But eventually the salvage yards reclaim the metals and this source dries up. It becomes very, very difficult to find parts.

The NHW11 is moving from 'early repairs' as collision coverage is dropped into the 'older repairs' age. It has reached the point that I can not recommend buying an NHW11 except to those who can 'afford' to keep them running.

Bob Wilson

 

Thanks but I found it via Dept. of Transportation page that I had to cut-and-paste to load it into Excel. I'll go back and check the reference and adjust the authorship appropriately. Regardless, this PDF file does a much better job of explaining Table 5, the source of my table. It also gives me a chance to discuss one change I made due to the USA practice of middle of the year model introductions.

The first entries in Table 5 compared to my version are:

	Column 1	Column 2	Column 3	Column 4	Column 5
0	Vehicle Age	Table 5	Year	Adjusted
1	1*	0.0530
2	2	0.0706	1	0.0706
3	3	0.0706	2	0.0706
4	4	0.0705	3	0.0705
5	5	0.0703	4	0.0703
6	. . .	. . .	. . .	. . .

The middle of the year model change is evident in the first row.

Although not universal, we often find new model cars introduced in the middle of the previous calendar year. For example, the 10 year anniversary of the Prius in North America was just a week or so ago. Also, the earliest deliveries of the ZVW30 (aka., 2010 Prius) were in May of 2009. So I had this problem of how to deal with a table whose first entry reflects the introduction of new models in the middle of the sales year.

What I did was drop the first year of the table, the "1*" and treated the first full year as the baseline by shifting the model year down to the next row. Had I not done that the first year would show 75% when I had the first year, 2000 sales of the NHW11. I had accurate first year sales number but only an approximation from Table 5, first row.

To achieve a more accurate and less confusing analysis, I simply shifted the model year scale which makes the subsequent analysis true to the information a vehicle owner or buyer will have. For example, we own a used, NHW11, 2003 Prius but I have no idea if it was sold in the last half of 2002 or first half of 2003, the year the NHW20, 2004 Prius.

Still, thank you for the link to the PDF and I will check my source. It is possible there were multiple authors and I would prefer to cite the author(s), of the PDF, Tracie R. Jackson, or the cited source from the PDF, Arcadis, Geraghty & Miller in a report entitled “Update of Fleet Characterization Data for Use in MOBILE6.” Having had my work once plagiarized, I am sensitive to the hurt it causes and appreciate the correction.

Bob Wilson

 

Yes. When I helped replace the traction battery in a 2001 Prius with 250,000 miles, it had other maladies that the owner had worked around.

The steering encoder problem was solved by a switch that removes power from the steering ECU. He does a lot of high-speed driving and manual steering is not a problem. In fact, there is evidence from a Julian Edgar hack that reducing power steering sensitivity improves 'road feel'. But in his case, a lot of highway driving, it makes sense to 'live with it.'

Bob Wilson

 

I've had a chance to read "Fleet Characterization Data for MOBILE6", EPA420-R-01-047, Tracie R. Jackson to try and determine who to credit for the table used for vehicle age. What I found is a mix of sources including Dept. of Transportation, Census data and a contractor, Areadis, Geraghty & Miller who did yeoman's work reducing the mass of data. However, it is clear that the EPA lead the effort and more hands than Tracie Jackson who documented how the analysis proceeded. This is one case where many hands turned to the task, beyond any one individual, department or contractor. They all did GOOD but for now, I agree that EPA takes the lead for organizing with honorable mention to DOT support.

Bob Wilson