I wouldn't worry too much , there are so many variables.ldallan wrote:I'm wondering if there are objective values to quantify "best battery friendly practices" contrasted to "battery unfriendly practices"?
I've seen plenty of posts mentioning "do this ... don't do that" to baby our batteries so they degrade slower, but I'm fuzzy on how much it matters. How "costly" is it to use DCFC fast charging in terms of battery degradation? How "costly" is it to charge to 100% rather than the recommended 80%?
For example for purposes of discussion, suppose our batteries with lithium-manganese-oxide with nickel oxide (LiMn2O4 with LiNiO2) chemistry would go 120,000 miles at 12,000 miles per year (10 years) with a range degradation to 60% by using "best practices" in an ideal environment:
* always use Level-2 6.6 kWh charging (220v - 240v) going from 20% to 80%
* never use DCFC (DC fast charging)
* never allow battery SOC to go under 20% (don't drain to LBW low battery warning or VLBW very low battery warning or "Turtle" or 0%)
* mild temperature like San Francisco or Ireland that don't get all that cold or that hot (mostly between 40°F to 80°F)
Contrasting to the above "best practices" to "non-optimal practices" that I've read on this and other forums:
* charging to 100%
* using DCFC fast charging
* freeway speeds in high heat like Texas or Arizona summers
* draining battery down to LBW, VLBW, or Turtle
Or perhaps using another quantifiable measure of battery longevity:
My limited understanding is that the Li-Ion chemistry used in our Leafs is rated for 300 to 500 full discharge/recharge cycles. About how many charges does it "cost" in terms of fewer lifetime recharges for using DCFC fast charging? Level-2 charging to 100%? Operating the vehicle in extreme Texas or Arizona heat at freeway speeds?
I don't think this is a hard rule. Just be careful of charge rate and temperature. It's hard with a 24kWh pack, as you can go over 2C pretty easily depending on the speed of the charger. But with newer, bigger packs you can charge at higher Wattages without straining the cells so much. A good rule of thumb is not to go above 1C, especially on days above 30 degrees celsius or so.ldallan wrote: * never use DCFC (DC fast charging)
The chemistry Tesla's chosen also is apparently much more volatile, hence the numerous examples of pretty crazy Tesla battery fires and cells going off like firecrackers.jonathanfields4ever wrote: That's part of why Tesla's battery packs are so great. They hit every tick box for what makes for long life. Chemistry that can handle a lot of charge cycles, a large number of small cells, large capacity to keep charge rate per cell low even if the Wattage is high, and of course the TMS. I don't know what person or team came up with their strategy or how much they're paid, but they need to be paid more.
Yeah, that’s a bit worrisome, but it’s also hard to know how much is hype and how much is spin. The media seems to really like going after Tesla. I saw someone on another forum (Fark) crunch the numbers and they found that Teslas are only slightly more likely to be involved in a fire than ICE vehicles. Furthermore, the majority of Tesla fires were caused by an accident, whereas a majority of ICE vehicle fires were caused by component failures.cwerdna wrote:The chemistry Tesla's chosen also is apparently much more volatile, hence the numerous examples of pretty crazy Tesla battery fires and cells going off like firecrackers.jonathanfields4ever wrote: That's part of why Tesla's battery packs are so great. They hit every tick box for what makes for long life. Chemistry that can handle a lot of charge cycles, a large number of small cells, large capacity to keep charge rate per cell low even if the Wattage is high, and of course the TMS. I don't know what person or team came up with their strategy or how much they're paid, but they need to be paid more.
See http://www.mynissanleaf.com/viewtopic.p ... 43#p336543 and the gm-volt post that it links to.
I'm only partway thru watching http://www.pbs.org/wgbh/nova/tech/super-battery.html that was aired last year and that I recorded on my TiVo in the past few months. They showed some examples of crazy battery venting and fires when li-ion batteries are damaged via various methods (e.g. compression, driving a nail into them, etc.) along w/some clips of YouTube from people trying such things.
No, that’s definitely true. The batteries seem to take the whole car with them when they go. It’s definitely disconcerting. But I think it’s also pretty apparent that the media likes the attention that comes from a Tesla headline. It guarantees a bunch of clicks and flame war (no pun intended) in the comment section.LeftieBiker wrote:I'd say that Teslas are less likely to be involved in a fire than a typical ICEV, but that the fires are more likely to be catastrophic. That's because of the cell chemistry, not media hype.