I am new to this forum, but not new to electric car driving. I have a 2016 Chevy Volt and a 2019 Chevy Bolt. I have been driving my Bolt for over two years. As a former Air Force pilot, I am very detailed in recording my energy consumption and range. Prior to the software update for the possible fire risk, my car was all within expected parameters. As of the update in mid-May 2021, it is no longer accurate.
I have been working with GM to try to get them to understand the problem, but I have not heard from them for some time now. Below is what I submitted to my Chevy dealer which is the only avenue that I have for getting info to GM:
2019 Chevy Bolt
Before the May 2021 software update for battery fire prevention everything was normal
After the software update the energy consumption readings are significantly off, and as a result the range estimates for the car are also significantly off. Both are now significantly incorrect.
As a baseline, here are some electric car energy efficiencies as measured by the EPA:
Most energy efficient: Hyundai Ionic - 248 watts/mile
Tesla Model 3 RWD - 259 watts/mile
Chevy Bolt - 283 watts/mile
Least energy efficient: Jaguar I-PACE - 443 watts/mile
Manufacturers like Chevy usually display that on the instrument panel as miles per kWh. For the 2019 Chevy Bolt the standard that is displayed after a full charge is 3.9 mi/kWh. Thus, the 3.9 is the normal miles that you can expect from the EPA rated 238-mile Bolt. I usually can get a bit better at around 4.2 mi/kWh in my normal driving. At highway speeds it will drop below that to around 3.5 mi/kWh.
I have analyzed this energy consumption and range every day for the over two years I have had my Bolt.
Here is a comparison of my driving readouts before and after the software update:
Before the software update After the software update
Read out: 4.2 mi/kWh 7.9 mi/kWh
Watts/mi 235 127
Range @ 60% charge 145 245
Since the new readout of watts per mile is roughly half of the most efficient electric production car, it is clearly not correct. In fact, I have verified that I am still getting roughly 4.2 mi/kWh by calculating the % SOC at the beginning of my driving and subtracting the ending SOC to determine energy consumed over the miles driven. This method is not quite as precise as the readout, but it does confirm that my car is still performing as certified by Chevy and the EPA. Thus, the battery appears to be fine, as well as the SOC readings and the time to charge readouts. I do suspect that any battery diagnostics will show nominal battery readouts.
Ramifications:
For me it is mostly an annoyance for local driving since I am confident in my SOC readouts. On a long trip with planned charging, even for me I am not happy because I cannot get real time readouts of my energy consumption. Forget the range displayed in miles, it is totally worthless.
For others who do not have as much technical knowledge of electric cars, at first it would be mostly happiness that they now have so much more range on their cars. That is until they take a trip counting on that range and end up out of energy on the side of the road.
For GM and Chevy, a potentially huge downside as they have not elected to replace batteries with the bad separators as did Hyundai and Kia. Their reputation is riding on this battery software update, and it is currently messed up (perhaps only in my car, but I suspect not). It is my hope that I can help provide enough information to the software engineers so that they can debug their program. A lot is riding on getting this fixed quickly and correctly…
