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I thought I read, perhaps here, that Tesla over-provisions its batteries and uses software to optimize the battery "working set" to minimize perceptible range d

by redler 9y ago

I thought I read, perhaps here, that Tesla over-provisions its batteries and uses software to optimize the battery "working set" to minimize perceptible range degradation.

yessql 9y ago
Tesla actively cools its batteries and chose a long lasting battery chemistry. The Leaf, does not cool the battery, and the early Leaf model had a really bad chemistry.
- cmrdporcupine 9y ago
  Not sure why you got downvoted for this. Nissan and some other manufacturers seem to be cutting costs by not doing the active cooling/heating that GM and Tesla are doing, and consumers are suffering for it. I was very disappointed to see the new Leaf is still not thermally managed. Air cooled only. Probably fine for California, but in places that have deep winters and hot summers, it's a bad idea.
  - yessql 9y ago
    Yes, I would have seriously considered the new Leaf, since it is about $5k cheaper than the Model 3. It would effectively cost $18k in Colorado vs $23k for the Model 3. It would be nice to have the Nissan service and manufacturing capability behind the product. But since it is still designed to degrade, I won't consider it.
  - WorldMaker 9y ago
    GM has said since the Volt was in pre-production they can't imagine why someone wouldn't actively manage the heating/cooling of a battery in an EV, because GM absolutely has to deal with Michigan winters. It's a strange "benefit" to classic Detroit car culture that they live in and take for granted at least one of the temperature extremes.
BuckRogers 9y ago
I'm sure they do, I thought this video[0] was pretty interesting. He took a bunch of Tesla owner's datapoints and mapped it out. The battery will basically last you 25 years. [0]https://www.youtube.com/watch?v=Gb_i4ihsJ1w https://www.youtube.com/watch?v=Gb_i4ihsJ1w
mikeash 9y ago
I don't believe they hide degradation. They do use less than the full capacity of the batteries in order to minimize degradation, though. Lithium batteries hate extremes, so if you map the official "0-100%" range to an actual range of, say, 10-90%, that will greatly prolong the life of the battery.
- jmiserez 9y ago
  Even without doing that, 0% on lithium ion batteries is not actually 0%. Because once you deep discharge it you can’t recharge it again safely.
schraitle 9y ago
This sounds like the Volt. It is software limited to only use the "sweet spot" charge range of the battery, so that it never gets fully charged or discharged. This means that over time as the battery degrades, the user would still see the exact same range due to the system expanding the min/max allowed charge.

by redler 9y ago

I thought I read, perhaps here, that Tesla over-provisions its batteries and uses software to optimize the battery "working set" to minimize perceptible range degradation.

yessql 9y ago

Tesla actively cools its batteries and chose a long lasting battery chemistry. The Leaf, does not cool the battery, and the early Leaf model had a really bad chemistry.

cmrdporcupine 9y ago
Not sure why you got downvoted for this. Nissan and some other manufacturers seem to be cutting costs by not doing the active cooling/heating that GM and Tesla are doing, and consumers are suffering for it. I was very disappointed to see the new Leaf is still not thermally managed. Air cooled only. Probably fine for California, but in places that have deep winters and hot summers, it's a bad idea.
- yessql 9y ago
  Yes, I would have seriously considered the new Leaf, since it is about $5k cheaper than the Model 3. It would effectively cost $18k in Colorado vs $23k for the Model 3. It would be nice to have the Nissan service and manufacturing capability behind the product. But since it is still designed to degrade, I won't consider it.
- WorldMaker 9y ago
  GM has said since the Volt was in pre-production they can't imagine why someone wouldn't actively manage the heating/cooling of a battery in an EV, because GM absolutely has to deal with Michigan winters. It's a strange "benefit" to classic Detroit car culture that they live in and take for granted at least one of the temperature extremes.

BuckRogers 9y ago

I'm sure they do, I thought this video[0] was pretty interesting. He took a bunch of Tesla owner's datapoints and mapped it out. The battery will basically last you 25 years. [0]https://www.youtube.com/watch?v=Gb_i4ihsJ1w https://www.youtube.com/watch?v=Gb_i4ihsJ1w

mikeash 9y ago

I don't believe they hide degradation. They do use less than the full capacity of the batteries in order to minimize degradation, though. Lithium batteries hate extremes, so if you map the official "0-100%" range to an actual range of, say, 10-90%, that will greatly prolong the life of the battery.

jmiserez 9y ago
Even without doing that, 0% on lithium ion batteries is not actually 0%. Because once you deep discharge it you can’t recharge it again safely.

schraitle 9y ago

This sounds like the Volt. It is software limited to only use the "sweet spot" charge range of the battery, so that it never gets fully charged or discharged. This means that over time as the battery degrades, the user would still see the exact same range due to the system expanding the min/max allowed charge.