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I got my 2018 volt LT in late Oct 2017. One day, while I was driving on freeway, 9miles remaining charge suddenly dropped to 0. The was just 4-5 days I had the car.

I took it to the dealership, they had my car for 2 weeks and I finally got my car back.

Two issues:
-The passenger seat is now mess up!
-They said they got me a new battery, but when i looked at the worksheet, I found that:
-They only exchanged a section of the battery
-One of the new battery modules is extremely overcharged, reading 4.995v
-One of the new battery modules is extremely undercharged, reading 0.786v (is it even possible)?

I found that the operating voltage of the LG chem is supposed to be 3.0v-4.2v, but this?

I am extremely concerned, but the car seems to be working now somewhat... should I be concerned?
 

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Discussion Starter #2 (Edited)
My 1 week new volt has a broken battery

My 1 week new volt has a broken battery.

drove it to the dealer and they said they will replace the battery. It turns out only a section of the battery is swapped, and the new battery has a module that reads 4.995v and 0.786v.

Really? Chevy... should I be concerned?
 

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My 1 week new volt has a broken battery.

drove it to the dealer and they said they will replace the battery. It turns out only a section of the battery is swapped, and the new battery has a module that reads 4.995v and 0.795v.

Really? Chevy... should I be concerned?
It's very difficult to read the service documents, but from what I can make out, your battery problem was fixed in the normal manner and should not return. The seat cushion seems to be a quality control issue and also made good under warranty.

The only concern I would have is that it took two weeks for the repairs. Some cars have initial faults that perhaps should be caught before delivery but often are not. The Volt is no different.
 

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Replacing one section of the battery isn't unusual, though we haven't seen a lot of battery issues so the sample is small. That wouldn't seem to per se suggest a problem. The voltage might be. How are you determining the voltage? (It may have been in one of the images but I can't read it). My guess, and it's just a guess, is that whether there is a problem would depend on what was being measured and when it was being measured. However, if the car is operating fine and you're not getting any messages the battery is likely fine.

No idea about the seat. Seems like that was replaced. Do you not like the replacement?
 

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They're supposed to balance the cells when they replace a battery section. I wonder if they forgot? Still, less than 1 volt seems dangerously low for a Lithium cell. I would try plugging it into your EVSE (Level 2 if possible) and fully charging it. The onboard charger will balance the cells any time the battery reaches its "full" SOC (the car won't indicate that it's done charging until this is complete). It should be fine afterwards.
 

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Madpcsupreme, from what I could make out in one of the documents, it seems they balanced the battery which means they would have corrected the voltage so it's within normal parameters.

What's the range you're getting now on a full charge? Is everything else good with your car? I hope you'll be able to enjoy it without any issues from now on, as many Volt owners do.
 

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My take on this is that the voltage monitoring pickup for a cell was not a good connection. This causes one cell to read high (in your case I think the high voltage range was saturated, 4.995 sounds like a 5V clip on readings) and the next cell to read low. If you take the high and low cell voltages and average them, you would get the actual voltage of the 2 cells - the 3.932 value. I work for a company that does large scale lithium battery systems, so I have seen this kind of error.
Yes, if the cell voltage was actually down around 1.0V, then the cell should be scrapped. Recharging a cell this low outside of a manufacturing environment could lead to growth of dendrites, and possibly a cell short circuit in the future. If we ever see a cell voltage this low we scrap the cell.
Reading the work order, it sounds like they checked the voltage pick-ups for these 2 cells and corrected the problem, so I would not be concerned about your battery's future.
 

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I would not be worried about the battery based on that tech report. I read it as they replaced a module and balanced the cells (after some initial difficulty balancing). Seems pretty normal to me.

The seat, on the other hand, looks terrible and I would have them fix it correctly.
 

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Discussion Starter #11
I took the seat apart today and found that the technician actually broken one of the hook from the seat cloth cover. I have to hand stitch the a piece of farbic on top and then zip tide it to the hole to fix the problem. Very very disappointed to the dealer's craftsmanship.

Why didn't I take the car back and have them fix it? it's because I afraid they'd say you open it you break it...

Anyways.... if the battery isn't a concern that I can live w/ it. Yes, I also think if the cell drop to 0.Xv it will not be possible to bring it back up.
 

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I don't know, brand new car--out for 2 weeks with a serious driveability problem? Read this: http://www.dca.ca.gov/acp/pdf_files/englemn.pdf

I would make sure all your concerns are addressed to your satisfaction.
Technically it's been out for 2 years. The car hasn't changed much since 2018 other than a couple software changes and the steering wheel material changing. Mine had a bad cell at 4000 miles, though, so it's definitely not a unique issue. They really need to up the quality control at their battery factories because I've seen quite a few Gen 2 owners on here who have had to get segments replaced.
 

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I had a similar failure in my 2017 Volt battery. One of the cell pairs in a module failed. I was disappointed that a new car would have a problem that would cause a major disassembly of the vehicle. I was also worried about the car being reassembled correctly. But parts fail and new parts sometimes have infant failures due to manufacturing issues. After several months and several thousand miles of driving since the repair, I can say I am totally happy with the outcome. I don't even think about the replacement anymore (unless I see a similar post about it). Just drive it and be happy. BTW---get GM to fix that seat cushion. Something like that would be something I would tend to look at every time I drove the car and irritate me. Its like your first dent or door ding--you always seem to notice it and make a big deal in your mind about it until it is fixed. You bought a new car it just needs a new cushion.
 

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Likewise, I had two cells fail in my battery. Likewise, the dealer had the car almost two weeks. That was several thousand miles ago, and all seems fine. I did get very strange (high) eMPG readings for about 48 hours after getting the car back. All has been normal since then. I chalk it up to false readings due to the replacement and conditioning.

Now if I could only magically improve my cold weather range....
 
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