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How Do You Check A Toyota Prius Battery?

Every day I get messages from people that ask me how to tell if their Toyota Prius battery is okay. Here are some tips and tricks the professionals use to check hybrid batteries.


When it comes to repairing your Toyota Prius Traction Battery, there are many ways you can go about it. If you are a DIY guy at home, you can fix and balance a battery for a few days and less than a couple of hundred bucks. If you have no idea how to fix your battery, there are other options you can find out here.

I think the hardest thing to tell, though, is when your battery is in pre-failure, and you have no idea. Or, if it is failing, what modules are bad that need replacing. With so many voices competing for your attention, I hope this article gives you some guidance on how to know for yourself how to test your hybrid battery.

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Finding The Right Tools For The Job
Finding the right tools to check your hybrid battery does not have to be expensive. The first thing you need to do is get yourself an OBD2 adapter. If you are having trouble figuring out which one will work for you, check out this article here about the Carista OBD2 Tool.

Carista is the best $20 tool for your Toyota Prius

Once you have this affordable tool in your hand, it is time to get the FREE Dr. Prius app from the app store or google play (whatever your flavor). Plug your tool into your Prius, turn it on, and open the app. Here is where things can get confusing for many people. If you want more detailed information check out this article here on how to read the Dr. Prius app.

Using Dr. Prius to determine battery state of health

The basics are you need to be looking for weak blocks, and if you have Delta SOC. These two things will tell you if your battery is suspect. One other neat thing about Dr. Prius is the battery life test. It is paid, so expect that, but it is incredibly accurate.

The software was developed by people that have spent years working on Toyota Hybrids. The software accurately can tell how much life is left in your hybrid battery. One more cool thing about the creators of Dr. Prius, they have endorsed Hybrid Automotive who sells the Prolong hybrid battery reconditioning equipment. They say it works and breathes new life into an aging hybrid battery. If you want to know more about that venture, read this article here.

Dr Prius logo for your Toyota prius No Money, No Problem. Test Your Battery For Free
So, maybe we say that you are near broke and need to know if your Prius is going to make it. No worries, you can find out if your battery needs help or not.

While this process is not as accurate as Dr. Prius' method, it still does give you an idea. Here is what you do. Start the car and check your battery level. Hopefully, it is about right in the middle or higher. Now go out and load the battery. What I mean by this, is driving the car, hard. While doing this (with no other vehicles on the road hopefully), monitor how long it takes for the hybrid battery to deplete down.

2010 -2015 Toyota Prius Battery Gauge

When accelerating for 10 seconds or more, you should see the battery level drop but slowly. Now, you need to find a hill or do some serious regen braking. If you are going down a slope, monitor how fast the battery level fills. If the battery level jumps up quickly and drains quickly, you are in phase 2 of 3 in your battery health stage.

Knowing where your battery is health-wise is a massive help to you as a consumer. When we allow the battery to get deep into phase two or three without doing a reconditioning process, we age the battery faster.

If you can find out your Delta State of Charge, or see what weak module blocks you have, this is a great indication you will run into an issue with your battery. The easiest way is monitoring fuel economy and how quickly your battery rises and falls. Typically with a hybrid battery that is suffering, your acceleration will be lackluster, and your MPG's will suffer also.

I hope this helps Prius or any hybrid owner with a nickel-metal battery. Thank you for reading, stay safe out there. Also, be sure to stop in and see us over on Facebook at Green Car Movement, a community for hybrid and electric car owners.

That is all for today everyone, thank you for reading. I look forward to seeing you in the next story. Toyota Prius V Owner Gives Over 22 Cats An Extra Life During A Rescue

Watch this Toyota Prius truck with a nice little bed and click to subscribe to Torque News Youtube for daily automotive news analysis.

Peter Neilson is an automotive consultant specializing in electric cars and hybrid battery technologies. He holds a Bachelor of Science in Automotive Service Technology from Weber State University. Peter is also an Instructor of Automotive Technology at Columbia Basin College. Peter can be reached on Linkedin and you can tweet him at The_hybrid_guy on Twitter. Find his page on Facebook at Certified Auto Consulting. Read more of Peter's stories at Toyota news coverage on Torque News. Search Toyota Prius Torque News for more in depth Prius coverage from our reporters


Pete (not verified)    April 17, 2020 - 11:38PM

Why is the Carista app getting such horrible customer reviews on Amazon?

Sounds like there's a separation between what is (now $30 and not $20 - April 2020) and obtaining a "pro" version of the app that is actually useful.
I was looking forward to checking it out there for a minute.


Peter Watson (not verified)    April 18, 2020 - 3:24PM

Doesn't the HV Battery test in Techstream give valid health? My 2005 reads 16.12 min vol and 16.33 max vol on the 14 modules.

Cliff elliott (not verified)    April 19, 2020 - 12:26PM

When i frist start my prius the mointer on dash always shows really low then it charges i just bought this car what u think ?thank u for your help

Frank Perkins (not verified)    November 4, 2021 - 12:42PM

So, I bought my 2021 Prius in March. It now has 12k miles because we took a wonderful trip from San Antonio to Seattle. I took it in for maintenance and there it sits. A battery did not pass the load test and the dealer foes not know when a new battery will arrive. I'm stunned. We loved the car but now what do we think after this fiasco? Lord have mercy.