[Mpower]

The answer is... nothing. They work fine and degrade normally just like regular cars and have proven to function more reliably than some known (German) problematic cars.

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Ten-year-old Toyota Prius vehicles still outperforming critics — Autoblog Green

The launch of vehicles like the Chevrolet Volt and Nissan Leaf has stirred up a debate over battery longevity. Critics say battery output will degrade and cite outrageous replacement costs as a possible downside to these breakthrough machines. Well, it turns out that skeptics posed similar concerns over a decade ago, when the Toyota Prius made its U.S. debut. Turns out, those worrywarts were too, well, worried.

Based on data gleaned from more than 36,000 Prius owners in its annual survey, Consumer Reports gives Toyota's best-selling hybrid top scores in terms of reliability and ownership costs. As we noted in January, CR set out to answer questions posed by skeptics by taking a 2002 Prius with 206,000 miles on it and putting it through a battery (get it?) of tests.

After extensive testing, CR's numbers show that the first-gen 2002 Prius returned an overall fuel economy of 40.4 miles per gallon, which is virtually identical to the 40.6 mpg that CR recorded when testing a new Prius back in 2001. Likewise, CR found that, with 206,000 miles on the clock, the old Prius' acceleration numbers had only dropped by a few tenths of a second for both the 0-60 miles per hour dash and the quarter-mile run.

While the tested Prius' nickel-metal hydride battery pack showed virtually no signs of degradation ten years and 206,000 miles later, CR's evaluation says nothing of today's radically different lithium-ion packs. Still, since we're a decade on in battery development and the OEMs behind the new batch of plug-in vehicles and hybrids are offering substantial warranties, there's a good case to be made that the critics might not always bear listening to.

[rajivanoj]

Its natural that, when a thing gets complicated than normal, there would be much conscious for quality and there will be lots of R&D on it.

Thats the reason, Hybrids will posses most strict QA, only then it would have been successful in market. So once things complicated, it will have longer service life. Thats my opinion

[dot]

Yes, I remember that when hybrids were launched there was skepticism around battery life and reliability. This 10 year data is really good PR for hybrid vehicles. Now with better battery and related technologies coming in, the hybrid/ electric cars can only get better from here.

[mdsaab]

I was under the impression that the honda civic hybrid sold earlier in india needed a battery replacement after approx 4 years. And that the price of the battery was over a lakh of rupees.
If thats not the case, then i wished i picked up the hybrid.

[theMAG]

The only concern might be lack of current environment-friendly disposal methods for these battery packs, when their time comes.

[Mpower]

Originally Posted by theMAG

The only concern might be lack of current environment-friendly disposal methods for these battery packs, when their time comes.

@Mag, yes it needs to be worked out but here is a lot of precious metal in those batteries so I'm sure people will recycle it in a proper way at least for the monetary benefit.

[SS-Traveller]

Do similar studies exist for electric vehicles - the Reva for example? Wonder how Maini (& now, M&M) propose to recycle batteries used in the Reva.

[sgiitk]

Good question. These are normal Lead Acid batteries, so will presumably go the way as the rest go - back to the manufacturer for recycling if you are eco-friendly otherwise to the neighbourhood batterywallah for throwing the acid into the drain, and using an earthen pot to melt the lead in.

What is worrisome is the new high end batteries - Li ion for one. The bulk of the research is on improving the power to weight ratio, reducing the memory effect, and not on durability. Things have improved from the NiCad and NiMH days but this is a bonus.

[Mpower]

On a related note, here are some milestones achieved by Toyota recently.

• 1 million Priuses sold in the USA
• 2 million Priuses sold globally
• 3 million Toyota Hybrids sold globally

Toyota Sells One-Millionth Prius Hybrid in the States - Carscoop