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I'm trying to decide if this is anything special or just sleight of hand. I really do NOT know the figures, but I thought Tesla's only charged the cells to 80%

I'm trying to decide if this is anything special or just sleight of hand. I really do NOT know the figures, but I thought Tesla's only charged the cells to 80% and discharged to 20% to save battery life. If you are doing a one off test, you could go from 100%-0% to get 40% more battery life. And the article talks about fancy chemistries, but then says: "As a proof of concept, however, the prototype pack used in the demonstration was powered by different cells. The capacity of more than 200 kilowatt-hours was provided by high-energy cobalt-nickel cells, while those intended for the Gemini line are still under development." So they used what might be normal high capacity cells. Maybe their battery has fewer structural components so they can fit more cells in. Maybe Tesla uses a different chemistry for longer pack life. It seems like anyone could get maybe 40% more range doing nothing at all by simply fully charging and fully depleting the cells, and if you took the highest possible energy density cells and shoved them in to the same space with less structural members, maybe you could get the rest of the range they claimed. In fact it seems like that's what they did. But that's not an innovation if the pack will wear out in a year, or weaken the structure of the car. Like I said I am just speculating here and I don't really know, but so far this doesn't actually seem like the company has anything special. I have a feeling that if Tesla wanted to, they could do the same thing for a single demo, but that they have competing engineering requirements that mean they don't do this in production.

robbiep 5y ago
Well the article says that the battery capacity has gone from ~100kWh to ~200kWh… so I think they’re actually talking real increased battery capacity?
- TaylorAlexander 5y ago
  I am wondering if, when Tesla sells a car as "100kWh", that is the available capacity (80%-20%) or if the total pack capacity. There would be reasons why they would want to go either way. But I think the biggest difference is probably that there are known high capacity chemistries with shorter longevity, which can be safely ignored for a one off test to drum up press for investors.
  - avianlyric 5y ago
    Total battery capacity. Tesla are know for not hiding battery capacity, and instead using UI to strongly hint you shouldn’t charge past 80% under normal usage. The exception to this rule is cars sold with a lower capacity, where the battery is capacity is software locked. But that’s a market segmentation thing, not a battery protection thing. I also think there was only a short period where this happened on the Model S. These days Tesla has the scale where it’s more economical to have multiple battery versions for each capacity, than it is to reduce manufacturing complexity with fewer SKUs (and software lock the battery).
NotSammyHagar 5y ago
You can set the charge amount, it's not just that percentage change. This isn't so hard to imagine. When I go on a long trip in my s85d car from 2015, I set it to charge to 100%. It hasn't hurt my battery life, model s that is 7 years old and 65k miles. I get ~5 miles less than original battery range at full. My day to day is 90%. You are exactly right that it's not an innovation if the battery can't last similar to almost 10 year's ago lithium batteries with heating and cooling of the battery packs. I think this is achievable today, just by doubling the battery pack (which would take some more space, so maybe these folks have something). Tesla's plan for the ever delayed new roadster was basically put two levels of their battery pack (double it) to get more energy to go faster, but all that energy made it go much further - not double range because of the added weight but a lot farther than a single battery pack.
- saas_sam 5y ago
  Only 5 miles less? That's wild. I have a Model 3 and I get like... 30 miles less than the original 300 at 100%.

robbiep 5y ago

Well the article says that the battery capacity has gone from ~100kWh to ~200kWh… so I think they’re actually talking real increased battery capacity?

TaylorAlexander 5y ago
I am wondering if, when Tesla sells a car as "100kWh", that is the available capacity (80%-20%) or if the total pack capacity. There would be reasons why they would want to go either way. But I think the biggest difference is probably that there are known high capacity chemistries with shorter longevity, which can be safely ignored for a one off test to drum up press for investors.
- avianlyric 5y ago
  Total battery capacity. Tesla are know for not hiding battery capacity, and instead using UI to strongly hint you shouldn’t charge past 80% under normal usage. The exception to this rule is cars sold with a lower capacity, where the battery is capacity is software locked. But that’s a market segmentation thing, not a battery protection thing. I also think there was only a short period where this happened on the Model S. These days Tesla has the scale where it’s more economical to have multiple battery versions for each capacity, than it is to reduce manufacturing complexity with fewer SKUs (and software lock the battery).

NotSammyHagar 5y ago

You can set the charge amount, it's not just that percentage change. This isn't so hard to imagine. When I go on a long trip in my s85d car from 2015, I set it to charge to 100%. It hasn't hurt my battery life, model s that is 7 years old and 65k miles. I get ~5 miles less than original battery range at full. My day to day is 90%. You are exactly right that it's not an innovation if the battery can't last similar to almost 10 year's ago lithium batteries with heating and cooling of the battery packs. I think this is achievable today, just by doubling the battery pack (which would take some more space, so maybe these folks have something). Tesla's plan for the ever delayed new roadster was basically put two levels of their battery pack (double it) to get more energy to go faster, but all that energy made it go much further - not double range because of the added weight but a lot farther than a single battery pack.

saas_sam 5y ago
Only 5 miles less? That's wild. I have a Model 3 and I get like... 30 miles less than the original 300 at 100%.