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Hello, everybody.

So I just finished compiling my historical data and calculating my battery degradation after 70,000 miles of driving. It's a bit higher than I thought it would be, but I did notice an immediate and significant drop off immediately following the software update. That could be due to either more accurate algorithms or GM actually "reserving" about 2 kWh of battery capacity. The result is, at this point, I'm seeing about 8% less capacity now than new (it was about 5% less capacity than new at the time of the update).

https://youtu.be/lqB3od74sV0
 

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As an EE, I see no reason to worry about that degradation after so many miles. The Bolt EV can run another 70,000 miles before the loss affects your true driving range. Many ICEVs have major engine overhaul, costing thousands of dollars before reaching 70,000 miles. You will spend more replacing tires than any other item in the Bolt. So keep your Bolt EV, and pass it on to a relative when you want to upgrade to a better GM EV, maybe an autonomous version of the Bolt EV.
 

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So I just finished compiling my historical data and calculating my battery degradation after 70,000 miles of driving.
You definitely won the lottery. Our 12/16 build Bolt, purchased 07/17, never showed more than 58 kWh usable. Since installing Torque Pro on 06/17/18, after both battery updates were done, we have seen 58.6-56.2 kWh total capacity. It sits at 56.9 kWh, today, at 16,819 miles. The last full range check I did back on 05/28/18 showed ~55.9 kWh usable.

The first two months we charged with the factory charge cord, first on 120 volt, then on 240 volts. We have always used hilltop reserve, except just prior to leaving on a long drive. We have done 9 DC fast charges from 1-3 bars up to 80-85%. The car has always been garaged, and plugged in when temperatures fell below 40F or rose above 90F. Most of the miles have been done by my wife, driving at or below the speed limit, in D. I have done about 20% of the miles, always in L, never using the brakes, at or 2-3 mph over, the limit.
 

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I'm not sure what my battery capacity PID number was when new, but after 31k miles, my Nov '16 build 2017 reads 58.3 kWh. Was at a low of 56.8 a couple of months ago, but then crept up to 58.3 after some heavy fast charging usage. Go figure
 

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If we are talking battery capacity as measured in torque pro, my 2017 reads 60 kWh as of my last few log sessions and I have put 18,000 miles on the car in the 6 months I have owned it with one 1100 mile round trip to Chicago, and one 2100 mile round trip to Coco Beach Florida. No idea what it read when new, I installed torque pro when I planned my first long trip where I was going to be using CCS charging.

I commute 55 miles round trip per day at 55 mph most of the way with a couple short sections at 45 mph or 35 mph, and for commuting I use hill top reserve and gentle acceleration. On weekends I am likely to drive 150 to 200 miles in a day, never less than 100 if I leave the house, so I charge up to full. I use L all the time, but when transitioning to a lower speed limit zone I coast in Neutral. On weekends I drive the car much more aggressively including a couple trips to the local 1/4 mile drag strip.

Later,

Keith

PS: I did have the battery monitoring recall done.
 

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@drdiesel1 - Got a reference handy? I'm wondering if L1 or L2 charging to full (or only hilltop reserve?) has the same effect. If not, it might indicate periodic (quarterly?) grooming by DCFC as a modestly-practical alternative to fuel additive worship. :)
 

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@NewsCoulomb - would you be willing to publish your raw data, measurement methodology, and analysis?
I'll probably have to do a follow up video on that (also explaining what was most likely the result of the software update).

The measurement methodology was very simple. I did NOT us TorquePro for this, as I've found it to have wild variances in its estimates. Plus, it's just not that easy to estimate capacity from a snapshot.

Essentially, on a first discharge (from full), I compared the kWh used to the battery percentage remaining (as displayed on the charger). I have several dozen instances over the life of the car where I was able to capture this data, and it does present a very regular downward trend in total capacity. The most consistent and accurate results appear to come from when my initial discharging of the battery from 100% was down to 1% to 5% remaining capacity (typically 52 to 58 kWh used). From there, I extrapolated the remaining capacity and determined the total available capacity at that time.

I used 60 kWh as a baseline capacity. That is what is quoted in GM's EPA filing documents, and I have no reason (based on my experiences) to doubt that accuracy.
 

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Many ICEVs have major engine overhaul, costing thousands of dollars before reaching 70,000 miles.
Many?
I cannot recall any vehicle,(excepting engines I used in racing applications), needing a "major engine overhaul" at that low mileage.
Short of running out of oil, or competing in the Baja 500 without an air filter, no modern ICE is that short lived.
 

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Many ICEVs have major engine overhaul, costing thousands of dollars before reaching 70,000 miles.

Many? I cannot recall any vehicle,(excepting engines I used in racing applications), needing a "major engine overhaul" at that low mileage. Short of running out of oil, or competing in the Baja 500 without an air filter, no modern ICE is that short lived.

I have to agree w/ Edchris. In the last 40 years, I have *never* had a "major engine overhaul, costing thousands of dollars" before reaching 70,000 miles. Nor have I known anyone personally who has had to do so.

On the other hand, I HAVE had to pay to do expensive repairs (starter motor, radiator, timing belt/chain, water pump, ...) that have cost somewhere between $300-$800, somewhere north of 100,000 miles. (Timing belt maintenance, about $300, somewhere around 60-90K miles.)
 

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Just did a 100 mile run today using 28.3 kWh, and leaving 52% battery according to the"mychevy" app. That would work out to 59.5 kWh capacity if you take .52 x 60 and add the 28.3 to it.

Later,

Keith
 

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@drdiesel1 - Got a reference handy? I'm wondering if L1 or L2 charging to full (or only hilltop reserve?) has the same effect. If not, it might indicate periodic (quarterly?) grooming by DCFC as a modestly-practical alternative to fuel additive worship. :)
No, Sorry! This was experienced on other vehicles. I myself have done this on my last PHEV.
I often turn off HTR and DCFC to full. I never monitor my car, but, it can't hurt. I run the AC
while charging to try and capture the same affect as I did in my PHEV. :nerd:
 

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I'll probably have to do a follow up video on that (also explaining what was most likely the result of the software update).

The measurement methodology was very simple. I did NOT us TorquePro for this, as I've found it to have wild variances in its estimates. Plus, it's just not that easy to estimate capacity from a snapshot.

Essentially, on a first discharge (from full), I compared the kWh used to the battery percentage remaining (as displayed on the charger). I have several dozen instances over the life of the car where I was able to capture this data, and it does present a very regular downward trend in total capacity. The most consistent and accurate results appear to come from when my initial discharging of the battery from 100% was down to 1% to 5% remaining capacity (typically 52 to 58 kWh used). From there, I extrapolated the remaining capacity and determined the total available capacity at that time.

I used 60 kWh as a baseline capacity. That is what is quoted in GM's EPA filing documents, and I have no reason (based on my experiences) to doubt that accuracy.
There is also a bit of an issue with your methodology, too. When you pull up to a charger, the battery has just been under load. I've noticed that after a while parked, the percentage remaining can increase as the battery recovers, even though it has not (yet) been charged.

FWIW, I just took a 182.1 mile round trip, with significant freeway travel. My Bolt claims I used 45.2 kWh. I charged to full before the trip, and ended with 23.92% remaining, and thus 76.08% used. 45.2 / 0.7608 = 59.41 kWh total usable capacity. Later in the evening, the myChevrolet app and changed from showing 24% charge to 25% charge, which might mean the usable battery capacity is 60 kWh.

In contrast, the PID value has gone from 1813 (raw reading, 60.43 in @Telek's coding, 63.45 in mine) in March to 1766 now (58.87 in @Telek's coding, 61.81 in mine). That's a 2.6% drop.

(FWIW, this recent trip is actually the deepest I've ever discharged the battery.)
 

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Sorta trending into side note territory, but I was observing my Bolt via Torque Pro as it charged from about 95% (Battery % DIC PID) to 100%. When that PID said my Bolt was 100% charged, the raw SOC PID registered 95.3%. My Bolt continued to charge for another 15-20 minutes with the charge rate slowly tapering down from 7.7 kW/32 amps. The raw SOC % crept up to 96.7% (all the while the Bat % DIC figur stayed at 100%).
Then when the charging completed, the raw SOC % went back down to 96.0%. from 96.7%. So I potentially "lost" 0.7% of charge when the Bolt's BMS finished charging and reset everything. I'm thinking if I pulled the plug right when it first hit 96.7%, I could have saved that 0.7% of charge for use.
FYI, when 100% charged, my raw SOC % usually registered 96.5-96.8% when new.
 

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Hello, everybody.

So I just finished compiling my historical data and calculating my battery degradation after 70,000 miles of driving. It's a bit higher than I thought it would be, but I did notice an immediate and significant drop off immediately following the software update. That could be due to either more accurate algorithms or GM actually "reserving" about 2 kWh of battery capacity. The result is, at this point, I'm seeing about 8% less capacity now than new (it was about 5% less capacity than new at the time of the update).

https://youtu.be/lqB3od74sV0
At work, I can't get to youtube. Can you just cut to the chase and provide the data? thanks!
 

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All of these measurements are well within the margin of error. I see no convincing evidence of any battery degradation, even after 70,000 miles. This is great news.

An ICE engine that only lasts 70,000 miles is highly unusual. However, various manufacturers have produced dogs over the years.

https://www.wheels.ca/news/here-are-8-engines-you-should-avoid/

https://www.hotrod.com/articles/0408phr-worst-automobile-engines/

A properly maintained ICE engine that isn't abused should last well over 100,000 miles. I have purchased four Hondas over the years: 1985 Civic, 1986 Civic, 2000 Odyssey, and 2002 Accord. All had over 120,000 miles on them when I sold them, and all passed smog checks with imperceptible hydrocarbon emissions, a sure sign that the valve stem guides and cylinder rings were still functioning perfectly. I cannot say the same about the transmissions in the Odyssey and Accord.
 
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