Can I ask how you get in to the service mode to display the cell voltage? I have been using an OBD2 running MyGreenVolt app on my phone but it is cumbersome to use.
2017 HV Battery Cell Data (Sharing)
I've mentioned here before that I record the battery cell data quarterly, in an attempt to predict a failure before it becomes a problem. I take a fully charged reading using Service Mode, after the battery has been fully charged a while, so the BMS (battery management system) would have completed the cell balancing process. I also take a reading from Service Mode at the fully discharged state. If the gas engine is running when I park, I'll wait for it to stop before powering off & entering Service Mode to take the reading. The total kWh used comes from the energy screen in the car.
I then enter the information into a spreadsheet to track it over time.
Since I now have a years worth of data over 25k miles I thought I'd share. What has changed over the year? Nothing I can detect. Hopefully it will stay that way for a while. If you'd like to add your own Gen2 data to the thread feel free. I just ask that you use the same method so it's comparable.
I cut the spreadsheet image into two parts here to reduce the width:
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I then enter the information into a spreadsheet to track it over time.
Since I now have a years worth of data over 25k miles I thought I'd share. What has changed over the year? Nothing I can detect. Hopefully it will stay that way for a while. If you'd like to add your own Gen2 data to the thread feel free. I just ask that you use the same method so it's comparable.
I cut the spreadsheet image into two parts here to reduce the width:
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Year 6 Update:
The cell data readings as seen below have been stable. The battery related issue not reflected in this data is the reduction in range. I bought this with my 52 mile work commute in mind, and have been driving the same route, speeds, and conditions for this commute since I bought the Volt in December of 2016. When new, I could always make the 52 mile work commute consistently on battery, with a few miles to spare. Now, the best I can get out the battery is 42-44 miles on this same route, and I use 8-10 miles on gas. The kWh used display in the Volt should not be relied upon to estimate battery degradation, as my readings are only down 1 kWh. I'd conservatively estimate actual degradation at ~2-2.5 kWh or around 18%. It goes to show if you are buying an EV, you should increase your required range by 20% when purchasing, to account for long term degradation.
![Rectangle Font Line Parallel Screenshot]()
![Rectangle Font Circle Pattern Parallel]()
The cell data readings as seen below have been stable. The battery related issue not reflected in this data is the reduction in range. I bought this with my 52 mile work commute in mind, and have been driving the same route, speeds, and conditions for this commute since I bought the Volt in December of 2016. When new, I could always make the 52 mile work commute consistently on battery, with a few miles to spare. Now, the best I can get out the battery is 42-44 miles on this same route, and I use 8-10 miles on gas. The kWh used display in the Volt should not be relied upon to estimate battery degradation, as my readings are only down 1 kWh. I'd conservatively estimate actual degradation at ~2-2.5 kWh or around 18%. It goes to show if you are buying an EV, you should increase your required range by 20% when purchasing, to account for long term degradation.
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