How do I know if a Prius battery has been replaced?

I made an appointment to look at a 2011 Prius with 153,000 miles on it, but then I remembered that a lot of batteries need to be replaced by then. I don’t see anything in the Carfax history about a replaced battery. Is there any way I can tell by looking at it that the battery has been replaced already? If not, am I better off buying a Prius that’s closer to 200,000 miles because by then the battery would almost definitely have been replaced?

Tough question. I bet, buy don’t know, that most Prius cars are running on their original battery, even at 200,000 miles. You might call a hybrid battery replacement shop in your area to see if there are ways to tell, and also to find out what it costs to replace the battery. It should be somewhere around $2,000, maybe less.

Whether it was replaced or not is not as important as how much life is left in it. When you pay a trusted mechanic for a pre-purchase inspection, ask if they can tell if replacement was made, it more importantly, how much life is left in the battery. There are a lot of small, individual cells that make up the Prius hybrid battery. They don’t fail all at once, it one at a time. There should be repair shops that can tell how many of the small cells have failed. If there are many failures, you could have the cells replaced or replace the entire battery if a lot have failed. Here’s an article that discusses Prius hybrid battery life. BTW, Toyota says the life is about 150,000 miles or 8 to 10 years.

The problem with 2010 and 2011 Prius is the gas engine, excess oil burning:
Toyota Prius Problems |

“Toyota says a Prius battery will last between 100,000-150,000 miles or between 8-10 years”

I’ve yet to find an actual Toyota site that says that. If we add ‘at least’ after ‘last’, then maybe it’s correct.

What I did find was the WARRANTY coverage period, which is more the minimum one should expect:

" Hybrid-Related Component Coverage: Hybrid-related components, including the hybrid battery, battery control module, hybrid control module and inverter with converter, are covered for 8 years/100,000 miles. The hybrid battery may have longer coverage under the Emissions Coverage. Refer to your Owner’s Warranty Information booklet for details. Starting with the 2020 model year, every hybrid battery warranty is being increased from 8 years or 100,000 miles, to 10 years from date of first use, or 150,000 miles whichever comes first."

In researching the Lexus NX plug-in hybrid that I am contemplating the purchase of, I was surprised to see that the motive battery’s warranty coverage is now 10 yrs/150k miles.

If I get any encouragement from my Oncologist when I next see her in June, I will probably place my order for a 2023 NX over the summer. Hopefully the microchip shortages will be less severe by then.

This is just my personal opinion but I would not purchase a used Hybrid ( or All Wheel Drive ) because not everyone really does the required service on vehicles .

Of course I hope the Serena knows that this is a lousy time to be buying vehicles and she has several threads here about vehicle problems . This might be one of those find something new that you can really afford rather then used .

I wonder if a Toyota dealer can determine if the battery or original or not? Perhaps there’s some proprietary software that can interface with the car’s ECU, etc.

Just a guess.

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The owners section of the Toyota website will show you the full dealer service history if you have the VIN.

One with close to 200,000 mi could still be on the original, but if possible have a trusted shop look over the car including the hybrid battery, more important is how often this has been serviced. Toyota moved these to a 10,000mi oil change interval but the 2010 in the family gets an oil change more like every 6,000mi. Most of the replacement batteries have a label for the company that supplied the battery.

this special software is called “TechStream” and indeed will show a lot of diagnostics, but from what I recall it will not have the manufacturing date.
It will also not show “failed cells” - that I can tell for sure.
It will show individual banks (not cells!) internal resistance and voltage, so it is possible to tell how well “balanced” the battery pack is, but this is about it.
Each bank is two modules, and each module is 6 cells on Generation 2 Prius.
Diagnostics is for banks, so you do not even get to know which individual pack is bad, have to go for other tools (like balance charger).
Still, it’s not a rocket science at all.