Don't Buy A New Toyota Prius Hybrid Battery - Have It Repaired Instead

I don't necessarily disagree with you. Since it helps if we both use the same numbers, I'll just use yours without verifying them.

If the average lifetime is 160k miles, that is the expected lifetime until the first cell failure. Generally nimh cells last 500-100 charges. That's a large window. Considering that the Prius battery has many cells (168 total in 28 groups of 6) you're likely to get your first failed cell early in the failure window. So that 160k miles is likely the beginning of the typical failure window, placing the upper somewhere nearer 300k miles.

This leads me to conclude that it makes sense to replace the first few cells. I'll probably repair 3 failed cells (replaceable in groups of 6) before replacing the pack due to the failure window.

Alternately you could replace each of the individual batteries in the pack, likely for less than a full replacement pack.

I'll probably replace my entire car right around 220k miles, since the car will likely be worth less than the replacement cost.

I agree that the band aid approach of just changing a cell or two may well have to be repeated periodically. I had my battery replaced at 147000 by Green bean for $1500. They came to my house, did the job and were gone in 90 minutes. At 13 months and 24000 miles later, all is still in food order. Their warranty was 5 years with no mileage limit. It is now lifetime. There is one limitation. If you don't drive the car for a 30 day period the warranty is void. Inactivity is the killer. I learned this the hard way. The guy I bought my Prius from had let it sit for months. Otherwise from what I read on the Internet, these batteries can last almost forever.

Prius website says all their hybrid batteries are under warranty 150,000 or 10 years.

I know it’s not exactly the same thing as a Toyota Prius, but I work on hybrid mass transit buses. The entire system is literally like a giant Toyota Prius. The transmission is just a scaled up Prius transmission that happens to have an extra reduction gear for operation below 15 mph. Otherwise it is identical to a Prius system just scaled up. It also operates at about triple the voltage because it is about 600 V. However it uses the same 7.2 V 6.5 amp hour battery cells that you would find in a Prius. It has been our experience that the vast majority of cells stay in excellent operating condition. Typically it is cells toward the middle of the pack that fail because they run hotter. Usually just replacing those cells results on a battery that will operate trouble free for years afterwards. I currently own a 2008 Toyota Highlander hybrid because with five kids I need a seven passenger car, and it currently has 217,000 miles on the original battery. If the battery ever failed I would want to replace just the cells that need replacing because a replacement remanufactured battery would exceed the bluebook value of the vehicle. Not only that but a vast majority of the cells would likely be perfectly good. Due to the way battery life is managed by the vehicles operating system, when it is at a “full charge” the batteries are actually only at 80% of the actual charge capacity. When the battery is “fully discharged” it is still at 20% of the actual charge capacity. This strategy drastically reduces the strain on the battery cells and allows them to last a very long time. The battery calls that don’t run hot tend to last an extremely long time. Many of our older hybrid buses are over 15 years old with over 1 million stop and go city miles on them, and about 85% of the cells are original.

You are correct the prius nickel metal hydride batteries last 100k-175k very rare they make it too 200k my prius hybrid battery failed at 147k. I had an option to buy a rebuilt battery as changing out cells imo is not a good idea. I bought a greentec hybrid battery with brand new cells for 1570$ including tax and installation. When one cell goes bad the others start failing too, Not worth the headache and worth the investment because my 2009 generation 2 prius is in great condition and I get average 47-53 mpg. Here is too another flawless 147k ;-)

I have replaced 5 individual cells over the last 3 years. First cell failure was around 185k mark im almost at 250k right now. Each cell costs about 30-40 bucks on Amazon or eBay. I have under $200 in repairing it myself. I have it down to under an hour to replace a cell. I know of at least 1 company who sells rebuilt packs for about 1500 to 2000 depending on year and they have a lifetime warranty. I'm assuming they offer that knowing people usually won't own the car long enough and if they do need to repair it they probably do the same thing I do. Super cheap. Quite frankly the best option.

I agree installing one at Toyota is crazy but after researching batteries I decided to just buy an oem prius battery from Toyota and have it installed at my local mechanic who charges just a fraction of what the dealership would have charged me. Now i did almost go with green bean battery company because of the warranty but I've been reading allot of reviews that when the batteries do go bad which they will becuaw they are rebuilt not new ones than they can give you a hard time replacing them. I took a little chance but after the original battery in my 2010 toyota prius gave me over 10+ years and 200k miles I thought why not get another of the same where I will take care of it better than I did last round. Oh and the gen 3 battery they gave ne has gen 4 cells in them so thats a plus!

Hi Tony. I just bought a 2007 prius from my friend, with 119K miles on it. the battery just failed. i'm trying to make a decision on how to replace it - modules or an entire new battery pack. you said going to the dealership is way too expensive, i agree. where do you suggest i buy a new battery from? i will then educate myself to replace it and do the labor.

I have to disagree 100%. My neighbor and her family have 6 hybrid toyotas and ive repaired the batteries in all of them. I've replaced anywhere from 2 to 6 panels at a time and have never had to work on the same car 2 times. The first one I did was 3 years ago and she does non emergency medical transport so drives everyday all day. So for less than $100 in most her cars in parts she has a car that operates as normal and saved alot of money. One of the cars has 200k miles on it since repair and no problems so I guess it depends on each person and how deep their pockets are to buy a whole replacement.

I worked in electronic instrumentation too. You don't need a DVM with PPM accuracy for this application, nor do you need the electrometer input that you get with the finest instruments. Those are for high precision applications or for use as NBS traceable transfer standards. The HF freebie/cheapie is adequate for most battery work.

The inexpensive meter shown is calibrated and accurate. It is sufficient for this measurement.