how to check Prius hybrid battery health

How to Check Prius Hybrid Battery Health (How to Test Prius Battery Cells)

Last updated on January 13th, 2023 at 08:30 pm

Whenever you want to repair your Toyota Prius Traction Battery, you should be aware that there is various method you can do it.

However, in case you are at home and you’re a DIY kind of person, then you can fix and balance your battery within a few days and save a couple of dollars for yourself. 

But in case you are someone who doesn’t have any idea about how to fix your battery, then our post today will help you on how to check Prius hybrid battery health.

Indeed, one of the hardest things is to know when a car battery is in its pre-failure stage, and you don’t have any clue.

Also, you don’t have clue if it is failing, or its modules that are failing which need to be replaced.

We believe that this article will give you the guidance that you need on how to check Prius hybrid battery health.

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How to Check 2010 Prius Hybrid Battery Health (How to Test Prius Battery Cells)

So as a car owner, how will you know whenever your Hybrid Battery needs servicing or replacement? Indeed, this is one of the reasons people are scared of buying a Hybrid Vehicle.

A lot of car owners will wait till the check engine light code comes on before anything is done.

Waiting till the check engine light turns on could be too late, so you need to do something immediately. 

So what if I show you a better way you can check the 2010 Prius hybrid battery health?

Even without any engine trouble code, you can know the health state of your 2010 Prius Hybrid Battery, this is called a Stress Test.

Stress testing happens to be a good test in finding the health state of your hybrid battery.

It is known that hybrid battery models are very reliable, though they wear out after a while.

My friend has a 2007 Prius with more than 250,000 miles and intended to know how the car hybrid battery was fine.

Note that this car’s 12-volt battery has already been changed about 4 times and its hybrid battery has been working fine.

Note that any car within the last 15 years has its diagnostic port which is known as OBD-II which pro mechanics uses to find out what is wrong via the car computers.

Meaning whenever the check engine light turns on, it is the port to examine. Although many devices enable car owners to solve this same problem via their laptop or smartphone.

You need 4 things to get hybrid battery health information; 

  1. The ODB-II hardware connection
  2. The software to read/write to ODB-II
  3. The car-specific PID codes and calculations
  4. The know-how of interpreting the data result.  

Please note that the cost of the software and equipment isn’t expensive, it’s less than $50 that is if you own a smartphone.

The ODB-II hardware connection

Currently, you will find many connections to ODB-II which cost between $20 and $2000. But the $99 Automated connector happens to be a user-friendly way you can wirelessly connect a smartphone to any car.

You should know that the app really does many things and also supports various other apps both on your smartphone and online.

The Software to read/write

The OBC Fusion App happens to be an advanced app that works with iOS and Android.

You can get the app for around $10 and also a $10 add-on is needed to read the Toyota codes. However, Torque is an option for Android.

The Car-specific PID codes

In case you make use of OBC Fusion and the Toyota add-in, then these specifics are not needed.

The PriusChat has some PID codes with various generations of the Prius. This means that writing incorrect PID codes to the car might likely cause a problem for the battery health. However, let’s stick to these two measurements.

The NameTheShortNameTheModeAndPID Torque App EquationMin ValueMax ValueUnitsHeader
The HV Battery The Block Lowest Volt The HVB Min V21D0(2.56 * J) + (0.01 * K)  – 327.68015The Volt7E3
The HV Battery The Block Highest VoltThe HVB Max V21D0(2.56 * M) + (0.01 * N) – 327.68023The Volt7E3

Interpretation of battery state 

Note that the state of the battery’s health might be gotten by the differences between the highest voltage bank and the lowest voltage bank. 

Here they are:

  1. The 0.20V = 100% acceptable efficiency
  2. The 0.45V = 75% acceptable efficiency
  3. The 0.70V = 50% acceptable efficiency
  4. The 0.95V = 25% acceptable efficiency
  5. The 1.20V = 0% acceptable efficiency (This is a bad battery which needs to be replaced soon)

Here are the Specific Steps

Just purchase and install an ODB-II scanner. You can use the TONWON OBDII Bluetooth Scanner so that after getting the Automated ODBII scanner you won’t get the extended codes. But before you buy, ensure the scanner is working with the app you are using.

Buy and install the app.  

As said earlier, OBC Fusion App costs about $10 and needs a Toyota add-in purchase inside the app which is $10, and needed to read the extended codes.

Now turn on your car and then click on Connect within the OBC Fusion app.

Then click the following:

  1. Diagnostics 
  2. PID Values 
  3. Menu
  4. Select PIDs 
  5. Toyota-Lexus-Scion.  

Doing these will allow you to pick what you intend to monitor.

Now click the HV Battery, then turn on the Battery Block Max Voltage and the Battery Block Min Voltage. Now you can turn on your Battery State of Charge. 

To see the car voltage change, then drive your car around. Whenever you stop the car and the ICE engine is off, just take a screenshot or write down the 2 voltages. 

Please you should do this several times whenever the car battery is near fully charged and when low. Meaning you shouldn’t take the readings while your engine is on or when braking. Though some expert recommends putting the car in the reverse while the brake is on and the ICE engine is off so you get a better reading. Here are my readings

Now for every reading you have, subtract the minimum voltage from the maximum. You might get the difference between .09 and .14 volts if you do it well. You can use your reading to see the health of your battery. Why Prius Won’t Turn Off & How to Turn It Off

How do you tell if your Prius battery is going bad?

In case you just bought a new hybrid car, you need to understand some of the signs of your hybrid car. And whenever this hybrid vehicle’s battery starts to go bad, then note that its symptoms are quite different than those of a conventional gas combustion engine.

Here are signs of hybrid battery failure

1. The Fuel Economy Decreasing 

In case you are not getting enough gas mileage that you should, then its likely indicates that your car battery is getting bad. It’s the job of the hybrid vehicle battery to provide enough energy to fuel your car. This means that when the battery starts to go bad, your car will revert to relying on the gas combustion engine as the only power source. Visiting the gas station regularly is a sign that your battery is failing.

2. Having Fluctuations In Charging State

If your car displays an erratic charge or it indicates that your battery is fully charged in a little while and then extremely low after a while, then your vehicle’s battery could be overcharging or unable to hold onto a charge.

3. Your Car Battery Will Not Hold A Charge

Whenever your car is parked overnight and you left it fully charged only to return in the morning and see it low again, then it’s a definite sign your hybrid vehicle’s battery needs diagnostic attention.

4. Your Internal Combustion System Will Run More Than It Should

Any internal combustion engine which starts to run more than it should be sending you info. This simply means it’s time to include a battery examination in your maintenance schedule.

5. Getting Strange Noise From The Engine

Any car battery which runs hot will alert the electric fan that it needs to cool down. This is because running a battery that is too hot might cause damages to the battery and its components. 

Conclusion on how to check Prius hybrid battery health

Indeed, a lot of car repair shops are not trained in battery Stress Testing, even though they might have the scan too to complete the test. Today, we have spent time educating you on how to check Prius hybrid battery health, note that after seven years, hybrid batteries will be out of balance and needs to be rebalanced to perform well and regain the expected high fuel mileage.

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