I have some mutually contradictory information about the longevity of NiMH battery packs, as used in non-plug-in hybrid cars (mostly by Toyota / Lexus, but there may be other brands as well).

On one hand, Toyota offers a 10 year / 350 000 km warranty on the hybrid battery pack at least in Finland. Also, Consumer Reports has a 206 000 mile test of the Prius, noting that the performance and fuel economy was identical with a 2 000 mile driven Prius, thus making it likely the battery was in a good condition, although this test was on two about 10 year old cars, thus testing only amount of miles driven and not amount of calendar years.

On the other hand, in a comment to the post Toyota Auris Hybrid sometimes is reluctant to enter READY mode, Paulster2 noticed that "you can purchase a remanned Dorman Battery Pack for a 2016 Camry off of RockAuto".

So, in general, how well typically do the NiMH battery packs last as a function of time and as a function of miles driven? Let's assume an intelligent control computer here, one that shallow-cycles the battery to obtain greatest possible longevity. I am at least aware that some Honda hybrid vehicles have had suboptimal control algorithms, thus resulting in early battery failure.

How common is a battery failure on hybrids when compared e.g. to a transmission failure on a car with conventional automatic transmission, or to an engine failure on any internal combustion engine powered car?

Let's make it clear that we're discussing the same thing: this question is concerned only with the hybrid battery pack, not with the auxiliary lead-acid 12V battery that will surely fail in a short amount of time.

  • How common are engine / transmission failures due to poor maintenance? And some cars can have their lead / acid batteries last for 10 years... But I suppose it does depend on what you mean by "short"...
    – Solar Mike
    Dec 20, 2017 at 18:12
  • Anecdotes are not data, but - when my first Prius died at 350,000 miles (570,000 km), the battery performed just as well as when it was new. (The failure was due to most of the steering and suspension wearing out - Scotland's roads are quite bumpy!). My previous vehicle (1995 Peugeot 405) needed a replacement gearbox around 160,000 miles. That's manual, not the automatic you want to compare with, but I'd be surprised if an automatic would be more reliable. Jun 1, 2018 at 10:54
  • @TobySpeight The e-cvt from prius can last 600.000 miles ;) hybridcars.com/…
    – MariuszS
    Jun 6, 2018 at 15:17
  • The solution to the problem described in the post you've linked to was due to the "regular" 12 volt car battery failing, not the hybrid battery Jul 26, 2018 at 15:06

1 Answer 1


All batteries have a number of cycles limit. Toyota was smart, and the Ni-Mh battery in their hybrid cars are charged between 40%-60%. This makes this battery healthy for a very long time. For example, when the battery has only 70% capacity after some time, it still works like new because it is charged only to 60%.

But hybrid cars still have transmission, the combustion engine and inverter. And these components are very durable too (because of Atkinson cycle, e-cvt etc).

In my opinion, you should simply check maintenance cost, Prius is the winner here.


The problem with Toyota Auris was resolved and related to 12V battery.

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