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Discussion Starter · #1 ·
I have a 2017 Chevy Bolt that I purchased from a dealer a little over a year ago. It currently has about 30,000 miles on it. Up until recently I was always getting 225 to 245 miles of range. I have always used hilltop reserve to maximize my regenerative braking capability. Within the last 3-4 months I have seen my full charge range increase to 300+ miles with no other intentional changes. It is real since I keep good records on the distance driven and charging applied. This seems very strange and wonder if anyone else has seen this.
 

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Yup. when you drive efficiently, minimize cabin heating and cooling, outside temps are around 70F, your GOM estimates rise. My guess is you are averaging 5-6 mi/kWh efficiency.

But fear not, winter will have the opposite effect and starting ranges will dip under 200 miles most likely.
 

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Discussion Starter · #3 ·
Your comments are absolutely correct. However, in my case, the time of this observation, has been for 15 months and during the warmer season of 2020 the range was always in that range of 220 - 245. Everything else being equal I would expect a gradual decrease in range. I always use no AC in summer and only heated seats when it gets cold For some unknown reason it appears that my battery pack can now take on more not less charge capacity.
 

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Your comments are absolutely correct. However, in my case, the time of this observation, has been for 15 months and during the warmer season of 2020 the range was always in that range of 220 - 245. Everything else being equal I would expect a gradual decrease in range. I always use no AC in summer and only heated seats when it gets cold For some unknown reason it appears that my battery pack can now take on more not less charge capacity.
When you say you keep good records on the distance driven and the charging applied, are you tracking the kWh used that's displayed on the infotainment screen when you shut off the Bolt, and the battery percentage in the MyChevrolet app? Those 2 pieces of data will be a more accurate way to calculate your battery capacity than relying on GOM and energy added.

Specifically, you would charge to hilltop reserve (which resets the kWh used to 0), and note the exact battery state of charge % in the MyChevrolet app. Then you would drive for a while, but stay above 70 miles of range remaining, and then note the kWh used on the Bolt's infotainment screen and the battery state of charge % in the MyChevrolet app. Your battery capacity calculation would be:

kWh used / (max SOC% - min SOC%)

A 2017 would have about 57 kWh when new, probably closer to low-mid 50 kWh now. If your battery was truly gaining 30% capacity (300 miles vs 230 miles), you would calculate something in the mid 70 kWh.
 

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Discussion Starter · #5 ·
I have 2 sets of data available to me. The first is a notation of the miles driven just before I do a full charge (in hilltop reserve mode) and the total Kwh consumed. The other is a spreadsheet of downloaded data from the OBD port monitor that is collecting data including charging location for our utility company. They are interested in how much energy is being pulled from the grid and what locations as they try and get an early look at how the developing EV market might change their requirements for supply infrastructure.

There is nothing different in the way I am driving. But in regard to charging, I had to start utilizing a public DC fast charger, since my level 2 charger is in my attached garage underneath my family room. Once the report came out of the first recall remediation not preventing at least one Bolt fire, and based on GM recommendations, I do not charge in my garage anymore.

The spreadsheet from my OBD download shows an 84.3% SOC after doing my last full DC fast charge on July 29. As of today, I am showing an SOC at 59.61% and I have traveled 123.2 miles. The dash says I have an estimated remaining range of 161 miles currently. However, I like to rely on the hard numbers (mileage and Kwh used) just before doing a full charge to reset the Bolt app to zero miles since last full charge. But my nagging question remains why am I getting more battery capacity (range) vs. last summer? If the battery capacity is really going up is this related to a car that eventually catches fire? Normally battery capacity should diminish with time.
 

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I have 2 sets of data available to me. The first is a notation of the miles driven just before I do a full charge (in hilltop reserve mode) and the total Kwh consumed. The other is a spreadsheet of downloaded data from the OBD port monitor that is collecting data including charging location for our utility company. They are interested in how much energy is being pulled from the grid and what locations as they try and get an early look at how the developing EV market might change their requirements for supply infrastructure.

There is nothing different in the way I am driving. But in regard to charging, I had to start utilizing a public DC fast charger, since my level 2 charger is in my attached garage underneath my family room. Once the report came out of the first recall remediation not preventing at least one Bolt fire, and based on GM recommendations, I do not charge in my garage anymore.

The spreadsheet from my OBD download shows an 84.3% SOC after doing my last full DC fast charge on July 29. As of today, I am showing an SOC at 59.61% and I have traveled 123.2 miles. The dash says I have an estimated remaining range of 161 miles currently. However, I like to rely on the hard numbers (mileage and Kwh used) just before doing a full charge to reset the Bolt app to zero miles since last full charge. But my nagging question remains why am I getting more battery capacity (range) vs. last summer? If the battery capacity is really going up is this related to a car that eventually catches fire? Normally battery capacity should diminish with time.
What is your kWh consumed at 59.61% state of charge? It should display when you shut off the Bolt.
 

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Discussion Starter · #9 ·
BTW, where do you get your starting and ending %SOC? The only place I have found it is in the report that is being downloaded from the OBD port monitor I installed. It does not appear to be anywhere as a discrete numerical value on my dashboard. I only have 20 green bars that would represent 5% increments.
 

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BTW, where do you get your starting and ending %SOC? The only place I have found it is in the report that is being downloaded from the OBD port monitor I installed. It does not appear to be anywhere as a discrete numerical value on my dashboard. I only have 20 green bars that would represent 5% increments.
I get it from my ODB2 reader as well, but one can also get it from the MyChevrolet app.

So 29.2 kWh / (84.3% - 59.61%) = 98.3 kWh

That's not physically possible, so there must be something wrong in the BMS calibration. Normally, I'd suggest charging to 100% and driving down low to recalibrate the BMS, but I don't recommend that given the recall on all Bolt batteries.

At this point, if you believe your dealership service department is competent, you can take your Bolt in with this information and ask for a diagnosis. Even if all they do is charge to 100% and discharge low, safer for them to do that than you.
 

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Discussion Starter · #11 ·
Thank you for all of your great insights! I believe you are on spot as to why I have this anomaly. I have never had my Bolt off of Hill Top reserve since I purchased it. It truly makes sense that currently my BMS has no correct calibration for a tre S0C zero and 100%.
 
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