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A comment on GM tells some Bolt owners to park 50 feet away from other cars. Parent comment

Re:GM tells some Bolt owners to park 50 feet away from other... by colechristensen on Wednesday September 15, 2021 @08:02PM (#28546124)
While nobody will come out and say it, I’m convinced based on some extensive early career battery system engineering and various evidence from tesla that what they do is put in much more raw capacity than they sell you and then limit with software the capacity of the battery.

Early in the life of the battery this leads to slowed degredation and as the battery agrees the software uses more and more of the raw capacity to make it appear like the capacity is being lost much slower than it is… then at some point capacity will fall off a cliff when the excess is depleted.

Comparable to how SSDs have capacity reserved for bad blocks.

It is probably good engineering but it would be nice for the mechanics to be sold truthfully and some level of control to be given to the owner.

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Re:GM tells some Bolt owners to park 50 feet away from other... by ihattendorf on Wednesday September 15, 2021 @08:08PM (#28546187)
I mean, you don't have to guess. There are plenty of battery teardown videos where they count the cells. IIRC it's on the order of 5-10% kWh reserved.
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Re:GM tells some Bolt owners to park 50 feet away from other... by nicoburns on Thursday September 16, 2021 @06:15AM (#28549895)
I'm pretty sure every product with lithium-ion batteries does this, but it's not so that they can use the extra capacity later, it's because letting these kind of batteries either fully charge or discharge is itself harmful to the batteries, so to get a useful lifespan you have to have some amount of extra capacity.
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Re:GM tells some Bolt owners to park 50 feet away from other... by robotbikes on Wednesday September 15, 2021 @10:01PM (#28547061)
I mean the Chevy Volt uses only 50% of it's battery capacity but it can more easily do that thanks to having a built-in gasoline engine that operates more like a generator for the electric engine. When I found out that they limited the battery for maximum longevity I was less stressed out about the battery life. They still degrade over time and until they become more modular like the Ultium system GM is putting into their next-gen EVs it's still a big costly single point of failure.
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Re:GM tells some Bolt owners to park 50 feet away from other... by cmrdporcupine on Thursday September 16, 2021 @01:47AM (#28548479)
It's not as high as 50%.
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Re:GM tells some Bolt owners to park 50 feet away from other... by tonyedgecombe on Thursday September 16, 2021 @02:30AM (#28548736)
This is clearly the case as every time there is a mass evacuation from somewhere they issue an OTA update to release more battery capacity.
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Re:GM tells some Bolt owners to park 50 feet away from other... by cmrdporcupine on Thursday September 16, 2021 @01:47AM (#28548477)
GM also does this with the Bolt and Volt. I was under the impression that Tesla did this less so.
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Re:GM tells some Bolt owners to park 50 feet away from other... by runawaybottle on Wednesday September 15, 2021 @08:18PM (#28546259)
Wouldn’t this be extremely easy to find out with a battery tear down/test?
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