This is an update (hopefully the last update!) in regard to the "Battery Danger" message I experienced. Here are the prior posts:
Original Post on 10 May 2023
Update 1 on 15 May 2023
BLUF:
I now have the car back with a new battery. The EV Concierge is reimbursing my fuel expenses while I had the rental car (which was also taken care of).
Potentially helpful background:
I traveled out of state to find & buy the Bolt EUV (with S&S and SC). I purchased the car in Feb 2023 and DCFC'd it 4 times on the drive home immediately after purchase. Since I've been home, I charged up to 80% nightly with the 32A / 240V charger that came with the car.
When this event occurred, I still had about 140 miles remaining even though the picture shows "Low".
What I learned when I picked up the car:
The car was towed in, horn still going off, on 10 May 2023. The tech disconnected the negative on the battery to get it to stop and parked the car in the far corner of the lot. The next day, Thursday 11 May 2023, the tech saw error code P0BBD (Hybrid Battery Pack Voltage Variation Exceeded Limit).
Apparently what happened here is the battery has contactors and all of those disengaged as a safety mechanism when the car saw this code. The horn goes off - possibly with the hope of draining the 12V battery if no one is around. If this were to happen while driving, the assumption is you'd still get the notice and you'd slowly lose propulsion power - so you'd have enough time to pull over and gtfo.
Anyway - the tech followed diagnostics and a bulletin had him contact Technical Assistance Center (TAC) for further direction. TAC had him put together a report and scheduled the local field engineer to come out ASAP which ended up being Monday morning. The field engineer had a device that plugged into the engineering port (on passenger side) to stream data to engineers in Detroit. It was then decided a battery replacement would be the resolution and the bad battery would be carefully packaged, crated, and sent to LG.
When the new battery was installed, the coolant was also replaced and the battery was programmed remotely by the engineers in Detroit (I think).
The tech also put the car on their DCFC which performs an isolation test and rebalances cells. He said it's free to use and it wouldn't hurt to do it monthly (the battery doesn't need to be at a certain level - just needs room to charge).
Let's get nerdy:
I got a copy of the diagnostic report it showed the following:

• Battery 1 & 8 @ 3.80V
• Battery 9 @ 3.85V
• The rest of the 32 batteries were at either 3.82V or 3.83V

He pointed out battery 9 as the outlier and said especially since it's in the middle of the pack so it's not near anything that would cause the increase in voltage.
I looked up how thermal runaway happens here are 3 possibilities:

• Overcharging: Charging a lithium-ion battery beyond its recommended voltage limit can cause the deposition of metallic lithium on the anode. This can create microscopic metal dendrites or "whiskers" that can penetrate the separator between the electrodes, causing an internal short circuit and leading to thermal runaway.
• Overdischarging: Discharging a lithium-ion battery below its recommended voltage limit can also lead to thermal runaway. Overdischarge causes the formation of copper or other metallic deposits on the cathode, which can cause internal short circuits upon subsequent charging.
• Elevated temperatures: Lithium-ion batteries are sensitive to high temperatures. Exposure to elevated ambient temperatures, excessive heat generated during charging or discharging, or external heat sources can increase the internal temperature of the battery. If the heat generated exceeds the battery's ability to dissipate it, a thermal runaway reaction can occur.
  • This can happen on batteries with higher voltages because they will discharge faster (more watts / more heat) compared to the other batteries.

One of the key reactions that can occur during thermal runaway is the breakdown of the electrolyte. The electrolyte in a lithium-ion battery is typically a flammable organic solvent that contains lithium salts. When the battery undergoes thermal runaway, the high temperature can cause the electrolyte to decompose or vaporize, releasing flammable gases such as ethylene and propylene. These gases can further contribute to the heat buildup and increase the severity of the thermal runaway event.
As the temperature continues to rise, the decomposition of the electrolyte and other active materials in the battery can accelerate. For example, the breakdown of the cathode material, which often includes a nickel-based compound, can release oxygen. Oxygen can react with other battery components, such as the electrolyte or the graphite anode, resulting in additional heat generation and the production of more flammable gases.
The release of flammable gases, combined with the high temperature, can create a self-sustaining chain reaction within the battery. The heat generated by the exothermic reactions can further accelerate the decomposition of the electrolyte and other materials, releasing more gases and causing a feedback loop. This feedback loop leads to an increase in temperature, pressure, and the release of additional flammable gases, exacerbating the severity of the thermal runaway event.
In closing:
I learned a lot and ordered an OBD reader from Amazon.
Bonus
The tech informed me if I were to try to change my own 12V battery whenever it needs it, there are some contactors that disengage and make a noise when the negative side is disconnected (always remove the negative side first). When putting in the new battery, if the contactors don't re-engage, you may need to have it towed in.

TL;DR: Inconsistent test procedures, incomplete details, and results that are incompatible with previously stated results make it impossible to draw any solid conclusions from the data
We finally have some more data on Hardge’s EMM device than the bits and fragments that have been found previously. Kudos to Cal for acquiring it from Hardge and sharing it publicly. Here’s my analysis of what has been shared. As usual, this is long, because the details matter.
The data shows dyno runs from two different days, the first on Jan. 5 (Run A) and the second on Jan. 20 (Run B). While there is nothing in the data itself that labels the runs such, it seems that we are supposed to assume that Run A shows the Mullen 1 cargo van without an EMM installed, while Run B is supposed to be the data for a van with the EMM installed.
SOC % Over Time
The tables shown indicate the battery State of Charge (SOC %) at different hourly time intervals. The data shows that the van in Run A completely ran out of charge after 5 hrs 37 min, while the van in Run B still had 44% of charge after that same amount of time. I put the data into a simple graph to show that based on the data presented the van in Run B (w/ EMM, we assume) clearly used less battery charge over the same time interval. If we extrapolate Run B linearly then the data implies that it could have run for a full 10 hours before reaching 0% SOC.
The graphs plot both Power (hp) and Calculated Speed (mph) as a function of Time (seconds). It essentially provides a timeline of how much power was required to rotate the dyno wheel at the indicated calculated speed at each moment of the run. It provides much more detail than the tables for Time and MPH, which appear to be manually recorded at far fewer intervals.
Run A Graph
Run B Graph
This is especially significant because the Run A graph displays quite a lot more variance in the vehicle speed and power, at least in the first half of the run, compared to Run B. When analyzing data, the differences can often provide clues for a meaningful understanding of the results.

Analyzing the Run A and Run B Differences

The reason it is important to carefully consider the differences is because we need to determine if the different results are caused by the device/phenomenon that we are actually studying, or by differences in the testing conditions. This is why scientists and engineers try to keep test conditions between trials as close as possible, in order to minimize the effects of environmental differences and make it easier to conclude that the result is due to the thing being tested. Unfortunately, there are several notable differences in the Run A and Run B testing conditions that may undermine how confidently we can conclude that the observed results were due to the EMM itself.
First, the NOTES indicate that Run A was conducted at a temperature of 63 F while the temperature during Run B was 74 F. Temperature can affect EV range, with collected data showing that EV range generally peaks at around 70-71F. This is due to a combination of the battery thermal management systems working to maintain an ideal temperature for the battery around that range, as well as the lower need for HVAC usage to maintain a comfortable interior temperature. The test notes indicate that “all acc on” for both tests, and Hardge has said in previous comments that this includes lights, radio, and even air conditioning. But the notes do not indicate what temperature the HVAC control was set to. A higher temperature would have the heater drawing more energy in Run A. To be fair, if the A/C was set to a lower temperature, then cooling would draw more energy for Run B. Without the details we are unable to assess the impact of the temperature difference.

Significant Fluctuations in Driving Procedure

But the data does show that there were significant differences in how the van was driven between Run A and Run B. The speed for Run B remains essentially flatline between 44-45 mph for essentially the entire run, and it is most likely that cruise control was set to maintain this consistency. In contrast, the first half of Run A exhibits significant speed fluctuation, with speeds dropping as low as 33 mph and rising above 53 mph, including two sharp accelerations that increased speed by about 15 mph. Even without overlaying the light blue lines indicating the range of speed for Run B over the data for Run A the fluctuations are obvious.
Speed Fluctuations
Fluctuating speeds can significantly affect energy consumption and range for an EV. This study showed that:

Driving speed oscillations negatively influence energy consumption of BEVs. The larger the oscillations, the higher the energy consumption. While small oscillations of 0.1 m/s^2 don’t significantly influence energy consumption, larger oscillations of 0.3 m/s^2 do (with a gain of 14% for eco-drivers, 37% for normal drivers and 53% for aggressive drivers).

Repeatedly accelerating and decelerating uses up considerably more energy than travelling at a constant rate of speed, causing up to 53% higher energy consumption according to that study. Those who have driven EVs for an extended amount of time know personally how different driving styles can impact efficiency. The exact same car driven over the exact same route in different manners can result in meaningful differences in the expected range (this very unofficial test showed a difference of 7% in battery charge from just a 30 mile drive).
This is also evident in the graph of Power between the two runs, with the power in Run A fluctuating significantly out of the range exhibited in Run B, with multiple periods showing double or triple the power draw. Again, the blue lines show the limited range of power draw for Run B compared to Run A.
Power Fluctuations
While it appears that cruise control was activated for Run B starting around the 12500 second (3.5 hour) mark, it is important to note that the cruise control was set to a higher speed of 53 mph, compared to the 45 mph speed set for Run B. The vehicle was then kept at 53 mph for more than 2 hours until the battery was depleted. In an indoor dyno test without the effects of aerodynamic drag, higher speed will have less of an impact on power, but there is still a meaningful difference. This is why the EPA uses different drive cycles to determine the EV efficiency and range at different speeds, and why the “city” rating is almost always higher than the “highway” range rating for EVs.
It is baffling why Mullen did not keep the driving profiles more consistent between Run A and Run B. The major differences in driving profile compromise being able to conclude that the greater efficiency displayed in Run B is due to the EMM as opposed to Run A being driven in a much less efficient manner.
This issue is compounded even more by the fact that only a single trial was conducted for each configuration. Everyone who has conducted scientific testing knows that multiple trials are important to average out the effects of random extremes. Why did Mullen chose to do only a single run with and without the EMM? Or, did Mullen and Hardge in fact do multiple runs, and cherry-picked only a single sample to share? It should be noted that it was a period of 15 days between Run A and Run B. Why did it take more than two weeks between the tests? We don’t even know if they used the same van for both Run A and Run B.

What about the Distance Travelled?

I will finish this post with one more factor I noticed that calls into question the legitimacy of the testing procedures performed. For a graph of speed versus time, the area under the line represents the total distance travelled. Using a tool like Graphreader allows you to plot out and generate a data set to match a given graph, and then with a bit of Google Sheet-fu we can derive the total distance travelled by the vehicle for each run.
https://preview.redd.it/iesv5qgitb3b1.png?width=1017&format=png&auto=webp&s=5e054035302f4afdce8a56237a3ed24079f69c55
I leave it to the reader to try it for themselves, but the result I obtained was:

• Run A = 262 miles
• Run B = 242 miles

With 44% SOC remaining and that distance traveled in Run B, a linear extrapolation would end up with a distance of 432 miles (65% higher than Run A) by the time the battery is fully depleted. But here is why this range figure does not make sense in light of what Mullen has previously stated.
In the PR statement that Mullen issued on April 20 (which remains deleted), Mullen stated that the testing of the EMM on the M1 “showed more than a 75% increase in range” (stock M1 is claimed to go 110 miles), resulting in a “calculated EPA estimated range of 186 miles”.
April 20 Mullen PR Statement
And yet the results shown in the data would imply that the estimated range ought to be an incredible 432 miles! Why would the company claim 186 miles as the improved result, rather than 432 miles? Are they not understanding the implications of their own data? Or are there some other factors that disallow claiming the 432 miles range?
But here’s another questionable aspect of this range value from the test results. Run A indicated that the stock Mullen 1 van travelled 262 miles total, which is nearly 240% the actual rated range for the vehicle. This strongly suggests that there are aspects with how the test was conducted that are unrealistic and depart from what you would see in real-world usage. You may recall that when Hardge had Element Materials test his golf cart, it was done with the drive wheels lifted off the floor and spinning freely, thus greatly reducing the load and allowing much longer (and entirely unrealistic) runtimes.
With so many details of the test procedures and other aspects of how the runs were conducted missing, it is difficult to draw any firmer conclusions based on what has been presented. Though at least it is more than what we had before.