# Prius 1998 what is the differance with the batteries



## evnz (Jul 24, 2010)

I have got a nhw10( mark one ) with batteries out of a nhw11 (dead) (mark two )whats the difference in amps and amp hour etc between nhw10 and nhw 11 bateries


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## Bob Boyce (Jan 30, 2009)

The original NHW10 used consumer grade 10 A/Hr Panasonic D cells in series to produce the nominal 288 volt traction pack. These cells had a functional limitation in charge/discharge rate that was enforced by the battery ECU and limited performance. 

Beginning with the NHW11 in the 2001 model year, Toyota began using a new rectangular Prismatic modules developed by Panasonic. These modules were actually 6 cells inside of a rectangular metal casing, with 38 of these modules in a series stack, clamped between metal plates held together by rods to prevent expansion and deformation. The capacity of these new cells was reduced to 7.5 A/Hr, and did little to improve the performance. The functional limitation in charge/discharge rates was still resulting in a limitation in performance. These performance limitations are what led to the reputation of the Prius being so slow. There were also battery leakage issues related to the sealing of the electrical terminals where they penetrated the module casings.

In mid 2002, Panasonic released a new Prismatic cell/module design. They increased the current carrying capacity of the electrical conductors within the cells and modules. This tripled the functional limitation in charge/discharge. This allowed the primary drive motor in the Prius driveline to develop much more power, and ended the days of sluggish performance. These new design cells required a new battery ECU, which is why they were not so compatible with older NWH11 models. These were introduced in the 2003 model year. To use a 2003 battery in an earlier Prius required updating all related ECUs and components that had been changed. This spelled the beginning of the end for the NWH11 Prius that so many had come to love.

This new development got the attention of other automakers. Automakers that had agreed that no large scale production electric automobiles would be built and sold in the US. Toyota was not a US automaker, and was not a party to that agreement. Panasonic had a Manufacturers License Agreement that permitted them to build consumer grade NiMH cells, but they were not permitted to build batteries for EVs. The early Prismatic cells were overlooked because the performance was not considered a threat to the auto industry. The new Prismatic cells had changed that.

GM bought controlling interest in US Ovonics, the patent holder of the NiMH battery technology. Using that as leverage, GM filed suit against Toyota and Panasonic, claiming they had violated the MLA that prevented Panasonic from manufacturing batteries for EVs. There was a settlement entered into, Toyota agreed to redesign the Prius and to turn over all unsold Toyota RAV4 EVs to GM for destruction. The automakers had also won a suit against the state of California which had mandated the production and sale of EVs in that state, so GM ended the EV1 project and slated those for destruction. The rest is history. The film 'Who Killed the Electric Car' documented what happened next. Since the details of the Toyota/Panasonic settlements were held confidential, the public was kept in the dark about GMs involvement in the end of the RAV4 EV and the NWH11 model of the Prius.

The DOE tests efficiency of vehicles sold in the US. According to the published data for model year 2003, the average vehicle efficiency in the US was 17% to 19%. The published efficiency for the 2003 NHW11 was a staggering 38%! That is double the highest end of the national average for that year. The redesigned Prius reduced traction battery KWH by reducing the number of modules in the battery unit. The engine horsepower was increased, as well as the horsepower of the primary electric motor. The inverter and motor voltage had been increased to 500V, which introduced further losses and contributed to premature traction battery failure. Overall, the efficiency of the later Prius was reduced to 28%. Still effective enough to make the car worth buying, but not nearly as good as the 2003 NHW11. I searched for and found 3 of the newer 2003 traction batteries out of NHW11s that had been totalled and sent to auto scrap yards. They are kept in storage for future use.

Why would I know these things? In 2007 I began a sponsored project to convert an existing vehicle for an alternative energy system. With the then current level of technology, I required a vehicle with an overall efficiency in excess of 33%. One of the criteria was that the vehicle had to be a gas/electric hydrid so that battery power could provide enough energy to provide for what would seem to be normal performance without relying solely upon engine contribution. The engine was relegated to powering the second motor purely as a generator. 

The project was a limited success, in that while it worked, a force within government shut down the project, claiming that the technology was a threat to the economy of the US government. I was told that this order had come directly from then president Bush. I will not go any further into what the project entailed.

Bob



evnz said:


> I have got a nhw10( mark one ) with batteries out of a nhw11 (dead) (mark two )whats the difference in amps and amp hour etc between nhw10 and nhw 11 bateries


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## samwichse (Jan 28, 2012)

Wtf with the necroposting and the whole bag of crazy?



Bob Boyce said:


> Why would I know these things?


You spent a reasonable amount on Prius Chat reading?



Bob Boyce said:


> The project was a limited success, in that while it worked, a force within government shut down the project, claiming that the technology was a threat to the economy of the US government. I was told that this order had come directly from then president Bush. I will not go any further into what the project entailed.


Please do.


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## Bugrug (Jun 7, 2016)

Just another case in point about new technology. When it first comes out, it will be expensive with flaws. Wait a few generations, while keeping up to date with their progress, and they will be better performing at a better price.


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