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Discussion Starter · #1 ·
I was shocked to see GM is only warrantying 60% remaining capacity on the Ultium Battery at 100K miles, Unless I am reading something wrong, this is very lame...

Tesla is 70%

Audi on 2019 E-Tron is 80%

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Discussion Starter · #3 ·
That is really a bummer to hear. I doubt I’ll own it at 100k miles as I tend to trade often. However, I am a huge hummer fan so I plan on keeping this one an extended period, like maybe two to three years lol
I have to think GM is just covering their butt for the customer that is DC charging and WTF daily, and they do not expect to see that kind of degradation? But its not great...
 

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Discussion Starter · #7 ·

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Yikes, 60% is awful. I wonder if GM doesn't have that much faith in their battery. That's like the Hummer dropping down to a measly 180 mile full-charge range before they'd replace it.
 

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Discussion Starter · #9 ·
Yikes, 60% is awful. I wonder if GM doesn't have that much faith in their battery. That's like the Hummer dropping down to a measly 180 mile full-charge range before they'd replace it.
I don't think that is it, I just think GM does not want to replace $30K battery packs that were abused. I am sure you have to abuse it hard and have some defects to get down to 60% in 100K miles
 

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I don't think that is it, I just think GM does not want to replace $30K battery packs that were abused. I am sure you have to abuse it hard and have some defects to get down to 60% in 100K miles
The pack wont be $30k. You change out individual units inside the battery pack. You replace whats broken. Its like doing a cylinder head gasket on a vehicle, pricey but you dont replace the whole engine
 

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Not true. Could have a couple of dead cells that wont take a charge thus limiting capacity of the battery ie dropping from 212 to 180
Dead cells will brick the vehicle and the battery will get replaced under warranty. The cells all have to be able to balance within a few millivolts, so one really bad cell will result in the module containing it having to be replaced. Failed cells and degradation are two completely different things. And GM really tightened up the battery monitor software after the Bolt recall, they do a lot more checks during charging now, looking closely at the balance of the cells.

Just for reference, I drove my 2017 Bolt to 103K miles before getting the new battery under the recall. It had lost about 10% capacity, and that is living in the Phoenix desert heat all those years.
 

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Dead cells will brick the vehicle and the battery will get replaced under warranty. The cells all have to be able to balance within a few millivolts, so one really bad cell will result in the module containing it having to be replaced. Failed cells and degradation are two completely different things.

Just for reference, I drove my 2017 Bolt to 103K miles before getting the new battery under the recall. It had lost about 10% capacity, and that is living in the Phoenix desert heat all those years.
10% in 100k miles doesn’t sound terrible. Not sure in Bolts but I know Tesla usually looses the most the first 100k miles and levels out some based on data from cars with 200-300k on them. If it started nose diving after 100k then you’d have a big problem. My guess would be with the Hummer if it was going to lose 40% of its capacity while under warranty it would do it fairly quickly and if you were very close to that as warranty was running out GM would good will it. This is their baby and cannot afford bad press after the Bolt battery issue
 

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Discussion Starter · #17 ·
Dead cells will brick the vehicle and the battery will get replaced under warranty. The cells all have to be able to balance within a few millivolts, so one really bad cell will result in the module containing it having to be replaced. Failed cells and degradation are two completely different things. And GM really tightened up the battery monitor software after the Bolt recall, they do a lot more checks during charging now, looking closely at the balance of the cells.

Just for reference, I drove my 2017 Bolt to 103K miles before getting the new battery under the recall. It had lost about 10% capacity, and that is living in the Phoenix desert heat all those years.
Why do you think GM went 60% while most of the rest of the industry is 70 +?
 

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Why do you think GM went 60% while most of the rest of the industry is 70 +?
My guess is, for the Bolt at least, that they did not really have much buffer in the battery (5% or less), and they claimed charging to 100% everyday was OK. Tesla also supposedly does not have much of a buffer, but they have always recommended charging to 90% everyday, 100% for trips. Ford also has 70% warranty, and they recommend 90% charge limit, even though they do have a big buffer (10%). I believe Etron also has a big buffer. When a manufacturer leaves a big buffer, they can always give you back some range on your car with a software change later on if it degrades below the warranty.

I think the Hummer may have a 5-10% buffer at the top, but I personally will likely only charge to 80%, which is what I do in my Mach E. After the Bolt battery fire issues, I normally only charge it to 88% now, that is the hilltop reserve setting. I used to always charge mine to 100%.
 

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Discussion Starter · #19 ·
My guess is, for the Bolt at least, that they did not really have much buffer in the battery (5% or less), and they claimed charging to 100% everyday was OK. Tesla also supposedly does not have much of a buffer, but they have always recommended charging to 90% everyday, 100% for trips. Ford also has 70% warranty, and they recommend 90% charge limit, even though they do have a big buffer (10%). I believe Etron also has a big buffer. When a manufacturer leaves a big buffer, they can always give you back some range on your car with a software change later on if it degrades below the warranty.

I think the Hummer may have a 5-10% buffer at the top, but I personally will likely only charge to 80%, which is what I do in my Mach E. After the Bolt battery fire issues, I normally only charge it to 88% now, that is the hilltop reserve setting. I used to always charge mine to 100%.
Ya, E-Tron has a top and bottom buffer, 95 kWh battery only 86 kWh usable. Tesla have almost no top buffer, maybe 1 or 2%, and at the bottom if you drive after 0% will drive into the bottom buffer for 10-20 miles. Tesla pushes it in this area.

What is usable kWh in Mach E?
 

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Ya, E-Tron has a top and bottom buffer, 95 kWh battery only 86 kWh usable. Tesla have almost no top buffer, maybe 1 or 2%, and at the bottom if you drive after 0% will drive into the bottom buffer for 10-20 miles. Tesla pushes it in this area.

What is usable kWh in Mach E?
88kwh out of 99kwh total. On the 22s they opened up the usable to 91kwh.
 
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