80% vs 100% charge

[Cosmo Cruz]

Thanks so much for this thread. I've been trying not to visit here so much because I post like I'm talking to friends at a bar and that gets me in trouble, but every day I learn things here. What an amazing community.

There is an EA charger 6 mi from home so even though I have a Betty Boop installed I haven't been using it. After reading this thread I went to my "home" EA charger and topped off (79%), (it's next to a Whole Foods so walked to buy dinner fixin's ... saw "charging complete" as I was just meters from the car after shopping ...having a perfect day). Now plugged into my BettyB as per these experts recommendation. My only issue is the charger cable is between door and workbench...

 

[SaaSManKS]

You know what’s funny I realized tonight about whether or not I want to plug in over night, it doesn’t matter bc when they update the charger to reverse power the house I’m going to want it plugged in to kick on! so guess I’m going in either way! Haha

 

[GMan]

If you are oNly charging once or twice a week, I would actually set it lower, say to 60% or 70% and just plug it in every night. I only charge to 100% if I am leaving for a trip the next morning.

Exactly what I do. Charge once a week to 66%. When it's time to recharge, I'm typically at 38-45%.

Early on, I saw some scientific report on car batteries in general and came away with using this 33-66% strategy as being highly effective over the long term.

My original post is here: https://lucidowners.com/threads/any...larity-when-battery-at-50-60.4463/post-109802
With my analysis here: https://lucidowners.com/threads/any...larity-when-battery-at-50-60.4463/post-110069

 

[bushav]

Our previous car was a Nissan Leaf. We leased the car for three years. Because of the short range we always charged to 100 percent. When we returned the car after three years the battery tested 100 percent with no degradation.

 

[DeaneG]

Our previous car was a Nissan Leaf. We leased the car for three years. Because of the short range we always charged to 100 percent. When we returned the car after three years the battery tested 100 percent with no degradation.

After four years, my 2011 Nissan leaf had lost 25% of its range. I charged it carefully. Nissan management wanted to ship the Leaf then even though its battery engineers thought it wasn't ready yet. Different battery chemistries will have different results: LFP vs NMC and other smaller formulation differences.

 

[xponents]

After four years, my 2011 Nissan leaf had lost 25% of its range. I charged it carefully.

This is what confused me... aren't Nisaan leaf's known for terribly bad BMS (and don't they tend to, as a result, lose a lot of their capacity)?

 

[DeaneG]

This is what confused me... aren't Nisaan leaf's known for terribly bad BMS (and don't they tend to, as a result, lose a lot of their capacity)?

Many factors determine battery degradation. Nissan Leafs do not have a battery thermal management system - they are air cooled. Also, the battery chemistry in early Leafs had a long way to go.

 

[MGRMLN]

Many factors determine battery degradation. Nissan Leafs do not have a battery thermal management system - they are air cooled. Also, the battery chemistry in early Leafs had a long way to go.

I leased a Leaf SL in 2015 and can attest to this. In an Atlanta winter, 25 -40 deg F, my Leaf would barely eke out 60 miles.
Contrast this to my AGT and I never have to worry and charge daily to 80% which more than enough.

 

[Sandvinsd]

After four years, my 2011 Nissan leaf had lost 25% of its range. I charged it carefully. Nissan management wanted to ship the Leaf then even though its battery engineers thought it wasn't ready yet. Different battery chemistries will have different results: LFP vs NMC and other smaller formulation differences.

After 5-1/2 years, our 2018 Nissan Leaf had to have the HV battery replaced under warranty. The Leafs have ZERO battery management since the battery is air cooled and as a consequence, there is substantial degradation,especially with high voltage charging. The upside to the battery replacement is that I have essentially a new EV with 80k miles on it and we will only L2 charge it as it is just a local car.

 

[Bus Driver]

Any harm in charging the car to 90%, and then letting it sit there for several hours, like all day?

 

[hmp10]

Any harm in charging the car to 90%, and then letting it sit there for several hours, like all day?

It's certainly not ideal. There's a reason Lucid suggests 80% as the daily charging limit.

The degradation comes mostly from the formation of dendrites on the negative electrodes of the cells, and their formation is a function both of state of charge and length of time. That's why charging up to only 80% makes it safer for the cells to sit long periods at that state of charge and why charging up to 100% just before commencing a long trip is relatively safe from time to time.

It is the combination of those two factors -- higher states of charge with long periods of sitting at that charge -- that is so damaging to the cells. The more of one you do, the less of the other you should do.

 

[Bus Driver]

Any harm in charging the car to 90%, and then letting it sit there for several hours, like all day?

It's certainly not ideal. There's a reason Lucid suggests 80% as the daily charging limit.

The degradation comes mostly from the formation of dendrites on the negative electrodes of the cells, and their formation is a function both of state of charge and length of time. That's why charging up to only 80% makes it safer for the cells to sit long periods at that state of charge and why charging up to 100% just before commencing a long trip is relatively safe from time to time.

It is the combination of those two factors -- higher states of charge with long periods of sitting at that charge -- that is so damaging to the cells. The more of one you do, the less of the other you should do.

Got it. Thanks so much.

 

[HariK]

There are lot of studies on this topic and I posted the details. Here is what is considered best for long life of battery.
On a daily basis best to maintain between 40% and 80%
Before a long distance trip OK to charge to 100% but ideal if DC fast charge is to 90 and top of 10% before driving
The worst thing to do regularly is discharge below 20 and charge over 90.

 

[Cosmo Cruz]

hmp10 is correct.

The dendrites grow and poke through the membranes shorting out the cell = overheating = inextinguishable fire.

The Lucid has nice monitoring features that shut things down and warn if you go amiss.

Lithium chemist here ... don't poke the bear.

80% to 20% gives incredible range in this car.

 

[Bill55]

if you remove the word "frequently" do you still have the same opinion?

Exactly how charging via Level 2 to 100% once a week compares to dc fast charging once a week from 20-80 has many variables.
I would not be afraid to charge to 100% on level 2 once or twice a week if that is what makes you most comfortable / happy with the car.
I have no plans to be a Million miler and rarely keep a car more that 4 years.
Over 2 1/2 years and 27k miles with many charges to 100% and most of the miles on road trips with dc fast charging, my battery had shown no appreciable degradation. Via a recall I now have a new battery so my observations have been reset to 0.

 

[Mawashi Geri]

Got it. Thanks so much.

I just went on a trip to China. Prior to leaving I was wondering if I should charge the vehicle and then unplug it or keep it plugged in through out my three week absence(daily 80%) like I have for the last 2 years without any issues. Please note that no one was home and that I was not having anyone check on it. My concern is the one in a million chance(my arbitrary chance number)that there might be am issue charging while I was gone. I called Lucid they suggested that I keep it plugged in and keep with the 80% daily charging or if necessary charge it to 100% and keep in unplugged. I chose to charge it to 100% and I also kept it plugged in, level set at 80% daily. When I returned everything was fine. To my delight the car did not charge while I was away. It was at 499 miles and only lost 13 miles of charge in over three weeks. The phantom drain was negligible. Definitely agree with what hmp10 mentioned but they gave me the option with emphasis on the 80% daily charge being the ideal solution. Unfortunately I had my concerns about charging while gone as I was having work done on my house and they would have been dropping the service power. This was my second 100% charge to date. I guess the main point for me is the phantom Drain is negligible. Next time I will charge to 80% and keep it plugged in.

 

[Chrome]

I just went on a trip to China. Prior to leaving I was wondering if I should charge the vehicle and then unplug it or keep it plugged in through out my three week absence(daily 80%) like I have for the last 2 years without any issues. ...Next time I will charge to 80% and keep it plugged in.

According to the manual:

Granted, it's anyone's guess as to what a "long period of time" is.