Objective measures for battery-friendly vs unfriendly practices?

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ldallan

Well-known member
Joined
Jan 16, 2017
Messages
52
Location
Colorado Springs, CO
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?
 
ldallan said:
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 wouldn't worry too much , there are so many variables.
Low SOC is not an issue (unless you have a bad cell pair) and high SOC is fine as well just don't leave it in either of those states for any longer than you need to.
DCFC is also OK just keep an eye on the temp
24kW batteries will get hot and more so 30kW batteries particularly after several DCFC sessions ( have had mine to 126 degrees +) after the 3rd session. :(
As far as charging cycles here is one from 2013 (over 1000)
http://www.mynissanleaf.com/viewtopic.php?f=9&t=11168&start=10#p266582
Another Leaf in Spain 325,000km

https://www.mynissanleaf.com/viewtopic.php?f=6&t=18805&start=10#p526601
 
This is all according to a Nissan dude I spoke with when I was first looking at LEAFs so I may be misremembering parts, but the chemistry of the LEAF battery before 2018 was particularly prone to damage from heat (even Lizard packs) and high charge rate simply because they used a cheaper cathode chemistry called MnO. It was the only way to keep the price down, but it's really better suited for industrial applications.

ldallan said:
* never use DCFC (DC fast charging)

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.

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.
 
jonathanfields4ever said:
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.
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.

See http://www.mynissanleaf.com/viewtopic.php?p=336543#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.
 
Honestly, people have been trying to quantify this on this board for a long time, and climate seems to override mileage or any sort of charging regimen as a predictor of degradation.
 
cwerdna said:
jonathanfields4ever said:
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.
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.

See http://www.mynissanleaf.com/viewtopic.php?p=336543#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.

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.

Food for thought.
 
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.
 
LeftieBiker said:
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.

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.

If I’m remembering that other thread properly, there are something like 400 car fires a day in America, and only 8% are from other fires spreading or from accidents. That’s a pretty interesting statistic. But questioning the safety of EVs and putting “Tesla” in your headline is a quicker and easier way to get eyeballs on your story. It’s even bigger if you piss Elon Musk off and he Tweets about you.
 
There's another thread similar to this one...

The question there is: Is it better to do one long charge to get to say 90% ... or multiple smaller charges to get to 90% battery?

Or put another way , is it bad to do many charges vs few charges?
 
be236 said:
The question there is: Is it better to do one long charge to get to say 90% ... or multiple smaller charges to get to 90% battery?

Or put another way , is it bad to do many charges vs few charges?
IIRC, Nissan advises avoiding charging if the battery is already at 70% or so. Obviously, if you've got to drive 70+ miles the next day, "charge away".

For my "use pattern", 70% is usually plenty for the next day. YMMV ...

Are you asking about doing several short'ish charges per day? Or nightly such as an average of 6 to 7 per week?

Bad? Perhaps "non-ideal" unless you are really into baby'ing your battery.

For us, there was a non-trivial, but interesting "learning curve" to the Leaf. Our nickname for it is "The Town Car". ;-)
 
ldallan said:
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

Well my Leaf has been through at least 3 of the above.

The first day I was bringing home the used 2015 Leaf, I let the battery go down to 13% and Low batter warning came on around 15%, IIRC.
That night I charged it to 100%.

A couple days ago I bought Leaf spy and found out that the previous owner has used QC over 800 times.

This car was originally from SF, CA. So I doubt it has seen Arizona like summers.
 
ldallan said:
* 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

We have owned our Leaf 2015 only for a bit over two months now, so I am still quite clueless about how to best take care of its battery to make it last as long as possible... it doesn't seem easy to find solid evidence on which charging practices are good/bad in terms of battery degradation.

In these couple of months I have used the CHAdeMO quick charging only once, the day I bought the car because I had to travel 80km on the highway (80-100 km/h) from the previous owner's city to ours, and the trip ended up using about 65% of battery charge. LeafSpy showed that the car had had 52 quick charges, and about 1100 T1/T2 charges.

Since that day, I've only slow-charged it from the home socket. I use only about 20% of battery charge on a regular working day (about 25-30km trip) so in the first weeks I basically charged it twice a week, plugging it whenever I went down to close to 20% and then charge it 4-5 hours up to around 80%. Then I noticed that the EVSE plug was getting quite hot, and changed my charging habits to 1-2 hours (almost) every day. Is this any good or bad?

A few fumbles I'm guilty on:
- I have this US EVSE that is not supposed to be used at 240V European voltage, I am looking forward to buying a proper EU-compliant EVSE; I don't think this has an effect on battery degradation, but there is a risk of hazard (although it's been used for 1-2 years by the previous owner)
- one day I totally forgot to unplug it :roll: so it reached 100%; eventually I drove it the next morning but it stayed at 100% during the whole night
- twice I got lost (thank GPS) while the charge was already quite low, and by the time I got home I was in LBW state, but never got to VLBW or Turtle

We live in a very cold country (Finland), and we're scared to venture farther than 50km from our town until spring. When the really cold weeks come, I am planning to just take a bus if the temperature drops below -15C :D
 
Your EVSE plug likely gets "quite hot" because it is being used at the wrong voltage. Many of the EVSE's components can handle it fine, but a few can't. You may also have a corroded outlet, with high resistance. Fix it!
 
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