2021 Bolt - HPCM2 replaced and only 52 kWh usable

Hi all,

Here is my story. My wife and I bought our first EV - a 2021 Bolt LT - on February 20, 2021 and immediately fell in love with it. About 4 week ago the service light came on (and went off 12 hours later) indicating a lithium ion battery issue (according to the OnStar email).

The car went into the shop the next week and was diagnosed with a faulty AC pressure sensor which required replacement of the Hybrid Module 2 (HPCM2) which took 6 days to resolve due to shipping delays.

After receiving the car back I did four round trips to work (107 miles each) and determined that I was getting severely reduced range. The last two round trips included carefully controlled speeds (55 mph and 65 mph, respectively) and almost no climate control usage.

I took the Bolt back to the dealer stating the reduced range (stressing the usable capacity is only ~50 kWh instead of 62-64). They came back with the lip service of driving style bringing it down as well as the aftermarket tires (Michelin CrossClimate2) we swapped in after about 600 miles.

I talked to the service advisor and EV tech that I had proof and showed them all the pictures and calculations I took during the two controlled runs. They finally caved and said they would escalate to Chevy corporate for a solution (they had exhausted all their tools for diagnosing what was going on).

Yesterday I charged to 94% and drove to visit family for the day and after the return trip I did another loop around the city to get the battery down to 4%. Here are the journey stats:

Net consumption - 90% (47.1 kWh indicated)
Total travel - 151.1 miles (47.4 mph average)
Efficiency - 3.2 mi/kWh (slightly worse than EPA highway estimate of 3.4 mi/kWh)
Energy usage - 95% driving, 5% climate, 0% battery conditioning
Ambient temperature - 54-56°F
Range impacts -
-15.1 miles (technique)
-5.5 miles (terrain)
-9.1 miles (climate)
-3.1 miles (outside temperature)
-32.2 miles TOTAL

Calculating usable capacity:
47.1 / 0.90 = 52.3 kWh

When I got home last night I plugged the car into the OEM travel charger and a P3 Kill-A-Watt monitor at 12 amps to measure the at-the-wall output to get it back to our standard 90% charge set point. When I plugged it in it was indicating 44 hours until completion (which would be 63.4 kWh added before charging losses), but I would imagine it will only be about 36 hours when it is all said and done (51.8 kWh). I’ll update tomorrow with the results.

I took pictures throughout all the trips to have plenty of evidence, and all we really want is to have the car back to how it performed when we first bought it three months (and 2100 miles) ago.

What is the community’s opinion on how I am addressing this? Are there other avenues to explore to get this car to perform as a brand new car should?

TL/DR - HPCM2 replaced under warranty at 1500 miles and now only have 52 kWh Of usable battery