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2021 Bolt - HPCM2 replaced and only 52 kWh usable

27829 Views 144 Replies 16 Participants Last post by  enslay
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
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Someone in my family, with a 2020 Bolt EV, noticed some degradation in range starting last February. It continued until April, where it became alarming.
After some back and forth with the dealer that considered it was due to winter tires and use of heating, a more serious investigation was requested because our computations (based on evident data from the charge station) lead us to estimate the battery capacity to 32 kWh.
The dealer finally looked into this more seriously. Following the detailed battery analysis, they concluded that one assembly within the battery was faulty and needed to be replaced. Due to parts availability issues (about a month), they decided to replace the entire battery (which they could get in 24 hours). Within 48 hours, the car was back on the road.
It took few days until the GOM displayed proper range. The car is now operating as it should.

I'm not saying it's the same but, the new 66 kWh battery in the 2020+ can be prone to issues. If you have evident data, ask for a more detailed battery check. You paid for this nominal autonomy.
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