Daily Home Charging Best Practice

[Steve F]

Okay Deane, that's even better. I was happy with the 19 years in my incorrect calculation above. But now with your correct information it is far greater than 19 years. So I will just continue to charge when my SOC gets down around 25% and charge up to 85% and not even begin to worry about battery degradation. I probably won't even charge once a week unless I'm doing a longer trip. I did read on another manufacturer's forum that their manual states it is good practice to charge up to 100% once a month or so as long as you don't let the car sit at that 100%. Also, apparently that manufacturer has a built in 5% buffer reserve so when you charge to 100% you are actually only charging to 95%. Not sure what buffer/reserve my Lucid has if any?? Also, not sure it really does make sense to charge to 100% once a month??

I would bet Peter built in a nice buffer. He seems like a planner.

 

[Steveinarizona]

Your interpretation is spot on.

Well...mostly. I would suspect that the 10,500 annual miles are not spread equally over 52 weeks. Some might be a vacation trip, many might be to a grocery store.

 

[DeaneG]

Okay Deane, that's even better. I was happy with the 19 years in my incorrect calculation above. But now with your correct information it is far greater than 19 years. So I will just continue to charge when my SOC gets down around 25% and charge up to 85% and not even begin to worry about battery degradation. I probably won't even charge once a week unless I'm doing a longer trip. I did read on another manufacturer's forum that their manual states it is good practice to charge up to 100% once a month or so as long as you don't let the car sit at that 100%. Also, apparently that manufacturer has a built in 5% buffer reserve so when you charge to 100% you are actually only charging to 95%. Not sure what buffer/reserve my Lucid has if any?? Also, not sure it really does make sense to charge to 100% once a month??

Every car's design is unique - chemistry of battery, size of buffers, BMS strategy. I'd follow the owner's manual recommendation for each car individually rather than reading one manual and following its instructions for the other car.

 

[DeaneG]

Here is a more detailed paper on battery degradation. See the middle chart in the screenshot below - this is for NMC batteries like ours, at 25C battery temp and 0.5C charge/discharge rate (a rate of charging or discharging that would go from 0-100% or 100% ro 0% in two hours), with three charge/discharge ranges:

Blue 40%-60% (longest battery life of about 2200 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)
Black 20%-80% (mid battery life of about 1800 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)
Red 0%-100%% (shortest battery life of about 450 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)

Each Equivalent Full Cycle (EFC) is charging or discharging by the amount of energy to completely fill and discharge the battery - like charging the car one time from 0% to 100% then driving until the car reaches 0% again. Or repeating five times: charge the car from 40% to 60%, drive until the car again hits 40%.

1000 EFC for a Dream or Grand Touring car would be about 400,000 miles. This huge number is a side benefit of driving a highly efficient car with a huge battery - one EFC takes you a long distance.

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[SaratogaLefty]

Here is a more detailed paper on battery degradation. See the middle chart in the screenshot below - this is for NMC batteries like ours, at 25C battery temp and 0.5C charge/discharge rate (a rate of charging or discharging that would go from 0-100% or 100% ro 0% in two hours), with three charge/discharge ranges:

Blue 40%-60% (longest battery life of about 2200 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)
Black 20%-80% (mid battery life of about 1800 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)
Red 0%-100%% (shortest battery life of about 450 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)

Each Equivalent Full Cycle (EFC) is charging or discharging by the amount of energy to completely fill and discharge the battery - like charging the car one time from 0% to 100% then driving until the car reaches 0% again. Or repeating five times: charge the car from 40% to 60%, drive until the car again hits 40%.

1000 EFC for a Dream or Grand Touring car would be about 400,000 miles. This huge number is a side benefit of driving a highly efficient car with a huge battery - one EFC takes you a long distance.

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Ok so if I use the 20%-80% charging (or my 25% - 85%) charging pattern I should be able to drive ~ 720,000 miles (1.8*400,000) and at that point I will have realized a 20% degradation?? So if I drive 10,000 miles/year, then I only have 71 years left (I've already driven the car for one year) before my range drops by 20%?? Well that seems pretty good; I just hope the seats hold up that long.

 

[DeaneG]

Ok so if I use the 20%-80% charging (or my 25% - 85%) charging pattern I should be able to drive ~ 720,000 miles (1.8*400,000) and at that point I will have realized a 20% degradation?? So if I drive 10,000 miles/year, then I only have 71 years left (I've already driven the car for one year) before my range drops by 20%?? Well that seems pretty good; I just hope the seats hold up that long.

Yes. Seat covers might be a good idea in 50 years or so.

 

[HariK]

Okay Deane, that's even better. I was happy with the 19 years in my incorrect calculation above. But now with your correct information it is far greater than 19 years. So I will just continue to charge when my SOC gets down around 25% and charge up to 85% and not even begin to worry about battery degradation. I probably won't even charge once a week unless I'm doing a longer trip. I did read on another manufacturer's forum that their manual states it is good practice to charge up to 100% once a month or so as long as you don't let the car sit at that 100%. Also, apparently that manufacturer has a built in 5% buffer reserve so when you charge to 100% you are actually only charging to 95%. Not sure what buffer/reserve my Lucid has if any?? Also, not sure it really does make sense to charge to 100% once a month??

I just looked at my use since the last charge to 80% on 3/15. Now 65%. That is because I have not driven much since then. I will let it run down to 20% and try charging at EA DC to 50% and see how long it takes to get to 20% with my local driving. According to the charging curve, that should be 150+ kW average. Let us see what happens when I do that. If others want to be included in my data collection, send me a DM with a screenshot of your Lucid EA charging session and SoC start, end and the ambient temperature. See example screenshot. I will summarize my data and post it here and send it to EA and Lucid. We should be happy if we get more than 1.5kWh / minute of charging on Lucid even though 20% to 60% should be close to 2 kWh / min. Right now, I am seeing barely above 1 kWh / min.

 

[DeaneG]

I just looked at my use since the last charge to 80% on 3/15. Now 65%. That is because I have not driven much since then. I will let it run down to 20% and try charging at EA DC to 50% and see how long it takes to get to 20% with my local driving. According to the charging curve, that should be 150+ kW average. Let us see what happens when I do that. If others want to be included in my data collection, send me a DM with a screenshot of your Lucid EA charging session and SoC start, end and the ambient temperature. See example screenshot. I will summarize my data and post it here and send it to EA and Lucid. We should be happy if we get more than 1.5kWh / minute of charging on Lucid even though 20% to 60% should be close to 2 kWh / min. Right now, I am seeing barely above 1 kWh / min.

Hi @HariK - wrong thread?

 

[SaratogaLefty]

Yes. Seat covers might be a good idea in 50 years or so.

All kidding aside, I do appreciate all of your research on this subject. I guess for me the bottom line is I will continue to use the local DCFC stations until the three year "free" usage runs out and I will charge once a week or so from 25%-85%. After the "free" period is up I will then charge during off peak at home using my LCHCS also once a week or so. I don't see any significant advantage to keeping the car plugged in every night. All of that said, once we eventually get the V2H capability I will most likely keep the car charged up all the time in case of a power outage. I do realize that using the car in that circumstance will probably contribute to faster battery degradation but even if it cuts it's life down to 200,000 miles I should be able to "live" with that.

 

[HariK]

Hi @HariK - wrong thread?

We have so many threads on EA and charging that I get lost lol!

 

[SaratogaLefty]

I just looked at my use since the last charge to 80% on 3/15. Now 65%. That is because I have not driven much since then. I will let it run down to 20% and try charging at EA DC to 50% and see how long it takes to get to 20% with my local driving. According to the charging curve, that should be 150+ kW average. Let us see what happens when I do that. If others want to be included in my data collection, send me a DM with a screenshot of your Lucid EA charging session and SoC start, end and the ambient temperature. See example screenshot. I will summarize my data and post it here and send it to EA and Lucid. We should be happy if we get more than 1.5kWh / minute of charging on Lucid even though 20% to 60% should be close to 2 kWh / min. Right now, I am seeing barely above 1 kWh / min.

Wow, that looks very familiar!!

 

[DeaneG]

In the center column of that 9-chart screenshot above, the center-top chart shows the effect of battery temperature while charging. Warmer is better for battery longevity - this is why EVs can charge at higher rates after "preconditioning" (generally warming) the battery. The center-bottom chart shows the effect of charge rate on battery longevity. Interestingly this chart shows better battry life at high rates of charge (3C would be about 350kW for our Dream/GT). I suspect this data anomaly is due to increased warming of the battery at high charge rates. If the battery were held at 35-40C ("preconditioned"), I think the result would be that lower charge rates give longer battery life.

 

[DeaneG]

We have so many threads on EA and charging that I get lost lol!

Charging is certainly a hot topic for the Air - it's my #1 concern and interest.

 

[HariK]

Charging is certainly a hot topic for the Air - it's my #1 concern and interest.

DItto. My focus is to provide specific data to EA and Lucid to help improve our charging experience and get the most kWh per min without damaging the battery life.

 

[DeaneG]

In addition to battery degradation due to choice of charging SOC range, there is also calendar degradation which varies with SOC and temperature. And degradation from DC fast charging. It's reasonable to expect our car's batteries to retain 80+ % of their capacity after ten years with normal care.

 

[AZLucidGuy]

Here is a more detailed paper on battery degradation. See the middle chart in the screenshot below - this is for NMC batteries like ours, at 25C battery temp and 0.5C charge/discharge rate (a rate of charging or discharging that would go from 0-100% or 100% ro 0% in two hours), with three charge/discharge ranges:

Blue 40%-60% (longest battery life of about 2200 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)
Black 20%-80% (mid battery life of about 1800 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)
Red 0%-100%% (shortest battery life of about 450 EFC - Equivalent Full Cycles - until only 80% capacity / 20% degradation)

Each Equivalent Full Cycle (EFC) is charging or discharging by the amount of energy to completely fill and discharge the battery - like charging the car one time from 0% to 100% then driving until the car reaches 0% again. Or repeating five times: charge the car from 40% to 60%, drive until the car again hits 40%.

1000 EFC for a Dream or Grand Touring car would be about 400,000 miles. This huge number is a side benefit of driving a highly efficient car with a huge battery - one EFC takes you a long distance.

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Great information. Thank you for sharing. So for my AGT, getting 400K miles out of 1,000 EFCs is more than I will need. These cars are amazing.

 

[Cosmo Cruz]

Wonderful. Searched to find a consolidated thread for this topic after posting all over the place like a newbe. Did the google and found all kinds of stuff that don't apply / aren't quite right for our unique Lucid batteries. Pretty much the on-line advice is: READ THE MANUFACTURER'S OWNER'S MANUAL.

Well I've been reading the book we got because I like books. This is wrong...throw it away. To understand the car you need to access the owner's manual through the pilot panel, or download the digital version. Go to p 144 " High-Voltage Battery Pack and Charging " and
pay particular attention to p 151

To sumarize:

Treat your Luci like a human: comfortable temps... don't starve her... don't stuff her ... take the middle path, stop often to smell the roses, and enjoy a long and happy life.

park in the shade when it's hot (plug in at home if > 100 F to keep the batteries cool and set to "daily" with a middle SOC range)
park inside when it's cold (plug in at home if < 50 F to keep the batteries warm and set to "daily" with a middle SOC range)
set your charge limits to "daily" if you don't need range for a longer trip. Try to stay between 40% and 80% for maximum longevity...closer to the middle is best.
Fast charging is for traveling. Level II ( low and slow) at home charging to "Daily" SOC range is best. If you don't think you need to go beyond 80% don't. Try not to go below 20%
Fastest charging at a 150 - 350 kW EA charger is acheived with lower SOC upper limit: you may find charging to 70% and then stopping at the next station and doing the same is much faster than charging to or beyond 80% and skipping a stop. We shall see. This would be great if EA stations were relyable / available.
If you have to leave your car unattended for a time (like at the airport) charge to the middle range and expect to lose some ... you can check this while away on the phone app.
If you are leaving your car at home while away = again, plug in and set range to lowest "daily" range.

not all the charging info is in the same place. I hate reading on a computer screen so I likely missed some stuff.

 

[Steveinarizona]

park in the shade when it's hot (plug in at home if > 100 F to keep the batteries cool and set to "daily" with a middle SOC range)

Thanks Lucid. Until I read this I deliberately parked in the sun when it was hot! This is like all those drug commercials on tv that say use "ABCD" unless you are allergic to "ABCD". Duh!

 

[SaratogaLefty]

Thanks Lucid. Until I read this I deliberately parked in the sun when it was hot! This is like all those drug commercials on tv that say use "ABCD" unless you are allergic to "ABCD". Duh!

But the problem with parking in the shade is that often means parking under a tree. Then you get the bird sh-t all over the car.

 

[Steveinarizona]

But the problem with parking in the shade is that often means parking under a tree. Then you get the bird sh-t all over the car.

Sometimes you are the fly, sometimes the windshield. Maybe they don't have birds in Seoul. Maybe they should have just said the best way to protect the car is not to use it!