Chevy Bolt first drive

[Warren]

On the 18th, I ran a Torque Pro log long enough to get 23 good scans of all 96 cell groups. I averaged the 23 readings for each cell group, and looked at the actual numbers for highest, lowest, average, and normally lowest cell groups.

The average cell group voltage was 4.020V...seen as last bar on graph
The highest cell group voltage was 4.032V...#9
The usual lowest was 4.010V...#70
The failing cell group was 3.943V....#47



Compare to a year ago.



The battery has gone from a total voltage delta of typically 0.024V to 0.089V, and a GM lottery winning below average voltage delta of 0.077V. This should get us a new battery ASAP.

 

[Warren]

An update on our Bolt. Cell #47 finally threw a code, and bricked our Bolt on August 25th. We had arrived home from a trip to Charlottesville, and I plugged it in to charge. Came out a bit later to see how it was doing, and the charge had stopped. It had added 16 kWh to the battery, when it figured out that cell #47 was not right. It showed 20 green bars/100% SoC, and a 12 mile range, at an actual 65% SoC.



Car sat in the garage for two weeks, with the 12 volt on a charger/maintainer, while I considered where to take it for the new fire recall battery. Cell #47 continued to fall ~0.002 volts every 24 hours, ending up 0.137 volts below the average by the time we took it in. Ended up taking it on a rollback to Charlottesville dealer. They had it done in three weeks.

The old battery was showing 162.7 Ah since June. The new pack shows 198.9 Ah, and I ran it from 100% to 3.9% on the very first charge. Usable capacity was just over 65 kWh, so I'm pleased, so far. Fingers crossed we don't see any failed cells for at least five and a half years, like last time. Some folks have had their new batteries fail within weeks to months. Also, some have thrown codes for failed cells, when none existed. GM's software is too sensitive, and can give false readings. If that happens, they install a software patch to back off a bit.

 

[Warren]

Can you explain the battery warranty on the Bolt and what is important about the battery lasting for the next 5.5 years?

Sure. The Bolt battery is warrantied for 8 years, or 100K miles. All Bolts are eligible for the new LG 64 kWh, fire recall battery, if they have not already had one installed. That battery has a new 8 year, 100K mile warranty. I mentioned 5.5 years, because that is how long our original LG 57 kWh battery lasted, before a cell died.

 

[Hillhater]

Whilst accepting the obvious issues with these LG packs, i still wonder how much of these apparent cell variations are a result of BMS/ software actions rather than actual physical cell defects.
I guess LG have analysed the crap out of all available evidence and concluded a manufacturing defect, but boy, the way those readings vary over time still leaves me uncomfortable about what their BMS/software is doing at times ?

 

[harrisonpatm]

Whilst accepting the obvious issues with these LG packs, i still wonder how much of these apparent cell variations are a result of BMS/ software actions rather than actual physical cell defects.
I guess LG have analysed the crap out of all available evidence and concluded a manufacturing defect, but boy, the way those readings vary over time still leaves me uncomfortable about what their BMS/software is doing at times ?

Your quandry seems to be from an outside perspective to be somewhat unknowable. We can speculate. The battery designers know who have studied the data. We can extrapolate from the smaller EV's we have personal experience with. BMS design language matters. Battery cells have manufacturing variability. Some are more preordained to fail earlier than others. Also depends on where Chevy purchases the cells from versus a company like Tesla who are known for good cell quality.
Suffice to say a complicated nexus between BMS design, programming and cell integrity. Unknowable what the precise interaction is.

On a related note, it's significant to note that LG chem batteries are now being produced in the US, in two factories in Michigan (driving distance from me, coincidentally!). I wish they had a better reputation and track record, but it's nice to know that there are at least attempts to get some high-level EV batteries manufactured closer to home.

 

[harrisonpatm]

Whilst accepting the obvious issues with these LG packs, i still wonder how much of these apparent cell variations are a result of BMS/ software actions rather than actual physical cell defects.
I guess LG have analysed the crap out of all available evidence and concluded a manufacturing defect, but boy, the way those readings vary over time still leaves me uncomfortable about what their BMS/software is doing at times ?

Your quandry seems to be from an outside perspective to be somewhat unknowable. We can speculate. The battery designers know who have studied the data. We can extrapolate from the smaller EV's we have personal experience with. BMS design language matters. Battery cells have manufacturing variability. Some are more preordained to fail earlier than others. Also depends on where Chevy purchases the cells from versus a company like Tesla who are known for good cell quality.
Suffice to say a complicated nexus between BMS design, programming and cell integrity. Unknowable what the precise interaction is.

On a related note, it's significant to note that LG chem batteries are now being produced in the US, in two factories in Michigan (driving distance from me, coincidentally!). I wish they had a better reputation and track record, but it's nice to know that there are at least attempts to get some high-level EV batteries manufactured closer to home.

Good to know for sure. May I ask what Michigan city the batteries are being manufactured?

One in Holland, one in Troy. From Wikipedia:

LG Chem Michigan is a wholly owned subsidiary of LG Chem based in Holland, Michigan[7] which operates a plant to manufacture advanced battery cells for electric vehicles. The US$303 million Holland plant received 50% of its funding from U.S. Department of Energy matching stimulus funds,[8] and started manufacturing battery systems in 2013.[9] The plant can produce enough cells per year to build between 50,000 and 200,000 battery packs for electric cars and hybrids such as the Chevrolet Volt by General Motors,[10][11][12][13][14] the Ford Focus Electric, and upcoming plug-in electric vehicles from other carmakers.[15] Its research and development arm, called LG Chem Power, is based in nearby Troy, Michigan.[16] LG Chem Power and LG Chem Michigan were originally one company called Compact Power, Inc.[17]

Both the Chevrolet Volt and the Ford Focus Electric initially used cells manufactured in Korea by parent LG Chem[18][19] and then later switched to cells produced in LG Chem Michigan's Holland plant once it opened.

 

[Warren]

Do you use the car primarily for short hop commuting? Are you pleased with it overall?

We are retired. It is our only vehicle. We use it for everything, including trips to Tennessee, and New York, to visit family. Back in June of 2017, when we got it, doing long road trips was an adventure. I recall doing a detour, to reach the nearest DC fast charger, that required crossing the state line, and added 75 miles to the trip. But we got to see the site of the oldest commercial windmill in the US, on a mountain top in North Carolina.

https://appvoices.org/2009/06/10/remembering-the-whooshies-of-%E2%80%9979/

DC chargers have gone in everywhere on the east coast since then. The only hassle for road tripping now is broken or full chargers.

In the moderate temperatures of the mid-Atlantic, even very long commutes are totally doable.

I owned some pretty exotic vehicles in my youth. The Bolt is the best car I have ever owned. It performs, and handles, as well as my old Sunbeam Tiger, but in complete calm, and quiet.

 

[nicobie]

Sounds like what you need is a plug in hybrid.

 

[Hillhater]

Whilst accepting the obvious issues with these LG packs, i still wonder how much of these apparent cell variations are a result of BMS/ software actions rather than actual physical cell defects.
I guess LG have analysed the crap out of all available evidence and concluded a manufacturing defect, but boy, the way those readings vary over time still leaves me uncomfortable about what their BMS/software is doing at times ?

Your quandry seems to be from an outside perspective to be somewhat unknowable. We can speculate. The battery designers know who have studied the data. We can extrapolate from the smaller EV's we have personal experience with. BMS design language matters. Battery cells have manufacturing variability. Some are more preordained to fail earlier than others. Also depends on where Chevy purchases the cells from versus a company like Tesla who are known for good cell quality.
Suffice to say a complicated nexus between BMS design, programming and cell integrity. Unknowable what the precise interaction is.

Unknowable for sure !
But its well known that Chevy used LG built and assembled packs,..together with an LG built power train !
LG had a good quality rep until the Bolt problems..infact it is known that Tesla have at times used LG manufactured cells ( cylindrical so not comparable) , as well as cells manufactured by Samsung and Panasonic.
Fundamentally , the difference is that the Bolt packs use pouch cells which have a history of problems no matter who manufactured them ..( A123, AES/Nissan, )
But at the same time , you cannot ignor the possibility of a defect in a BMS system initiating a pack failure.
To me it is a “chicken and egg” type senario, with the current consensus (from LG) , ..suggesting the Bolt pack issue is cell related.
..However , BMS is one area that i believe Tesla does have full control over design and manufacture.?

 

[Warren]

In the moderate temperatures of the mid-Atlantic, even very long commutes are totally doable.

What a difference a few months can make. lol We are fine with our garage, and no snow here in central Virginia. We were only out of power for 2 hours, and 10 minutes on Friday, due to high winds. But much of the country have had a real mess. The EV forums are alive with amazing stories. There are folks who are driving their Bolts around in -22 F and snow. The takeaway has been, if possible, plug in to keep the battery warm. No different than block heaters.



The charge efficiency is being considered 100%, because it is not going into the battery, but directly into the resistance tankless battery heater. Onboard charger is showing 98% efficiency.