New Hybrid Battery?

Welcome to PriusChat!!

Are you the original owner?

What makes you think it is failing?

An 07 with 104K actual miles would benefit from a top balance, or a couple of charge/discharge cycles.

When they replaced the 12v battery, did they also clean the MAF sensor?

Is it normal, or is it failing?

Didn't know you could run a health test with techstream, and I think it would need some reconditioning at 30%.

Would this relative also be expected to do the reconditioning, or HV battery replacement?

Can you post the data here. Unlikely that a failing HV battery will just die and leave you stranded, there will be a warnings lights first.

How many hours per week are you currently driving?

You might consider taking it on the freeway for 10 or more minutes once a week.

Yes, generally speaking it is safe to drive.

Tell us more about the vehicle maintenance history; Example: oil changes, replaced the inverter coolant pump, and the transmission fluid.

FYI : you're moderated until you've posted 5 times.

 

With your battery now 15 years old and living in a warm environment, it will naturally start exhibiting signs of age. Fluctuations with the state-of-charge is one of them, reduced efficiency is another. That means asking the tough question... how much longer do you plan on keeping the car? Odds are, the original pack won't fail. You'll just end up with a car with reduced power depending heavily upon the engine. A new pack should squeeze out a few more years of service. With such a tough car market right now, that may be a realistic option to explore.

 

Get a Prius compatible code reader under OBD2 or OBD following links

iOS and Android
Hybrid battery diagnostic and repair tool for Toyota and Lexus

Android Only
Hybrid Assistant: App

If you aren't mechanically inclined or if family member or you can't interpret Techstream head over to Luscious Garage or Nates

https://www.natesgreengarage.com/
https://lusciousgarage.com/

 

it sounds like it is showing it's age, but so is the whole car.

reconditioning now is a good option to extend the life.

track your gas mileage by calculating at fill ups. if you have never done this, you don't have anything to compare to previously, and will have to make your best guess.

 

driving will keep the battery happy. so will the AC in the heat. but i’d say forget the battery is there until it needs to be replaced.

 

Unless you see a triangle with an exclamation point, it is likely your car is safe to drive.

I highly recommend downloading the Dr Prius App to an Android Device or iPhone. I'm not sure how much Dr Prius costs (may be free or $35). You will also need an OBD2 device to plug into your OBD2 reader (under the dash). Be sure to check out Hybrid battery diagnostic and repair tool for Toyota and Lexus which tells you which OBD2 readers are compatible or not.

The Dr Prius app displays the current voltages of each of the 14 blocks (Prius Gen 2) and SOC%. If you click the red record button, the app will capture the voltage and resistance of each block, MPH, amps being charged/discharged, temperature, and charge limit each second. When you click the record button again, you will then be given an option to email or share a csv formatted log file. If you open the csv file in Excel, you can then save the file as an excel file, allowing you to format the columns, and even color code the cells based on values.

I like copying the 10 block voltages and add formulas to divide a block voltage by 2, to represent the voltage for a single module. In my car, the cell voltages tend to be close to each other, so it appears there is some active balancing taking place between the 14 blocks. When the car is discharging the cells, the voltage may get down to about 6.88 volts, and can be back up to 7.40 volts within one second. The amps being put out at this time was 96 amps for the pack. After the car has been running for a few minutes, the voltage range is around 8.40 volts to 8.65 volts. When the brakes are applied, the cells are being charged and the volts jump to as high as 9.52 volts.

The Dr Prius app also has a feature that will tell you the SOC of the battery pack and if some of the cells are bad.

On a side note, I may have damaged my modules by charging them up to 8.70 volts, which is about where the Delta V drops, indicating the module is fully charged. I think if you charge too high or too long, the chemical that triggers Delta V is used up, so the Delta V won't tell the charger to stop charging. So in my car, the battery manager may be charging the cells to higher voltages than it should. Any feedback on this would be helpful.

In any case, the block voltage of 16.23 volts means the cells are about 8.12 volts. If I charge a cell up to 8.25 volts, many of them will discharge down to about 7.88 volts, however some will stay at 8.10 volts. If a cell cannot hold a voltage of 7.20 volts, then the cell is bad. Other than that, voltage alone does not tell you too much. A cells internal resistance may be too high and a cell may charge up or discharge much faster than other cells which is also bad.

Regarding the catalytic converter, you could read this blog that describes problems a Prius owner had after the catalytic converter was replaced. The O2 sensor may have some wiring issues. https://automotivetechinfo.com/wp-content/uploads/2022/05/Diagnosing-Prius-Hybrid-Battery-Pack.pdf

Also, you should consider replacing the spark plugs and cleaning the full injectors which can help with gas mileage.