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Model 3 SR+ LFP Battery Range, Degradation, etc Discussion

AAKEE

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Jan 8, 2021
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1,863
Sweden
The link of the graph in my previous post is of LFP. It shows 3.2V at 20% SOC.
This is a voltage curve of a new CATL LFP. I didnt use any time to try match the CATL LFP cell Tesla use. Its about the right size, and a recent model.

Take note that this is a 0.5C discharge curve ( like driving so fast that it goes from 100 to 0% in two hours).
The open circuit voltage will be higher, and the voltage with the car parked and looking at SMT will also be higher.

The X-axis shows Amphs. We have 8 fields (0-20, 20-40 etc.)
SOC-wise, the first 0-20Ah will contain more energy then the other and much more then the 160-180Ah field.
The first field will contain more than 1/8 of the SOC and the last will contain much less than that, maybe 1/10 or 10% or slightly less.
You probably have the 8.8% mark at about the 140Ah or precisely right of. So, that looks like 3.17 V or so. If the battery is unloaded from that 0.5C load, the voltage increases. Most probably up to the 3.20V line or so.
666D8297-2F70-40E8-9D2E-5F7301C8A05E.jpeg


CATL 161Ah LiFePO4 Battery
 
Any info on calendar degradation for LFPs? Tessie (see sig) will not be driven much.

So my observations on calendar degradation:

Background:
I live in Tasmania, Australia, a cooler state which you would expect would help the battery longevity as the battery remains cooler but not freezing.
Had my '22 RWD for 8 months, almost no fast charging, Gen3 wall connector charged, and driven for the most part very gently, stays garaged with Sentry off.
Car gets weekly charged back to 100%, but not kept at 100% constantly.
Only done 3150km (1957miles) total to date.
was 439km (272 miles) to start like most, now showing 430km (267 mile) range. 2% apparent loss.

I notice people on these forums and others that have done far more km (10,000-30,000km) seem to have about the same range reported still or fairly close to my car, so perhaps calendar degradation is going to be the primary form of degradation for LFP models given my car has done so little driving and treated so well?

Granted the BMS could potentially be out of calibration though it has been discharged a few times recently to near empty then back to full so you would like to think it would have some idea about it's own state of charge health.

If anyone was wondering I do have access to a dongle and Scan my Tesla and the usable kWh capacity does directly relate to the remaining range displayed. My car was about 58.4kWh usable reported to start, now it's about 57.2kWh (2% apparent loss) & the cells in my car do seem to be well balanced.

I guess it's early days still but time will tell, fair chance the initial apparent 2% degradation over 8 months may slow to say 1% over a year for a well treated rarely used car with an LFP battery.
 
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AAKEE

Active Member
Jan 8, 2021
1,238
1,863
Sweden
perhaps calendar degradation is going to be the primary form of degradation for LFP models given my car has done so little driving and treated so well?

Well, yes!

Calendar aging stands fort the absolute most part of the degradation for more or less anyone, at least the first five years, probably 10 years in many cases.

The degradation to miles driven charts or discussions is not really very related as ”miles” has a much lower impact.

This is also valid for LR cars that do not use LFP.

For LFP the stated bumber of cycles is 3000 FCE or more, maybe 4-5000 in some cases. Lets say that it will hold 3000 cycles before loosing 20% (the industry limit is most often 80% remaning capacity as the batteries start to get unpredictable after loosing 20%).

A full cycle on a 55-60kWh LFP battery takes us about 250-300km (155-185 mi) ?

3000 Full cycles then takes us 750.000-900.000km ( 466.000-560.000mi).

On a average a car might be driven 15.000-20.000km (10.000-12.500mi)?

Annual cyclic degradation 15.000/750.000 x 20% = 0.4%

The annual cyclic aging will not be worse than 0.4%. In many cases, smaller cycles will keep this number even lower.

Even if the initial calendar aging is very low on the newest LFP’s lile 2% first year or so, calendar aging will not be as low as the cyclic aging until between year number 5 and 6.
Still, in this case, cyclic aging is probably counted too high and the calendar aging might be higher so it is probable that it takes longer time until calendar aging is as low as the cyclic aging.
 
35,000 mile (56,000 km) update for my Sep 2021 SR+ LFP. The car is now 14 months old and was originally rated at 253 miles on a full charge. The Tessie app shows a battery capacity of 52.5 kWh (down 3.8% from my original 23 Oct 2021 post of 54.6 kWh), and a max range of 243 miles (down 4.0% from my original range of 253 miles). I've had Tessie since my first day or two or ownership, so this data shows the entire life of the car.
Screenshot_20221101-204344.jpg


According to the car's screen, I'm now averaging 213 Wh/mi over the life of the car (down from 214 at the 30,000 mile update). Seasonal temps and driving style are HUGE when it comes to the car's efficiency. In the winter I can expect 240+ Wh/mi, and in ideal temps (75-85f) I routinely manage under 200 Wh/mi on my 100 mile roundtrip commute. Assuming I could tap into the current 52.5 kWh battery at my lifetime average 213 Wh/mi efficiency, that gives me a real-world range of 246.4 miles.
PXL_20221101_221721209.jpg



My charging is mostly Level 2 from a Grizzl-E delivering 24 amps on a 40 amp circuit in my garage. I charge most nights due to a long commute, typically to about 70-80% a few times per week and a 100% once or twice a week. I do fast charge about once per week on average due to a side gig that requires long days of weekend deliveries...I use both Superchargers and CCS chargers like Electrify America or Chargepoint, depending on which are more convenient at the time.

Tessie says I've spent $964.59 on electricity for the life of the car, while the same driving in my old Ford Focus would've cost $3,436.03 in gasoline. So my fuel costs have been 28% compared to keeping my old car. Assuming the average US emissions of 0.85 pounds CO2 per kWh, the 7,484 kWh used while driving equates to 6,361 pounds of CO2 spent driving my Tesla. If I'd kept my 2012 Ford Focus (37mpg), I would've used 948 gallons of gas to travel these 35,108 miles. At about 19 pounds of CO2 per gallon, that would've been 18,012 pounds of CO2. So I'm spewing 35% of the carbon emissions than I would've released in my efficient little Focus. As the grid moves toward more renewables, that should only get better over the life of the car. Also, my Focus would've had 225,000 miles on it now, so I'm pretty sure I'd have replaced it by now anyway.
Screenshot_20221101-204605.jpg



As an aside, I did a very long one-day trip last month, showing the ability to stretch the Model 3 well beyond what people might expect. I drove to pick up our new dog from a shelter out of state. On the bottom-right corner of this ScanMyTesla screenshot, you can see I drove 813 miles in one day. It was raining and the wind was blowing hard for most of the trip, so it was not ideal conditions. I left home at 2 AM and returned home at 10 PM, so I spent 20 hours in my SR+ driving 813 miles, with an hour in the middle meeting with the animal rescue people. There was one stretch in rural Missouri where I couldn't make it between DC fast chargers and had to stop and Level 2 charge each way, just to add a couple extra percent to make it to the next Supercharger--on a nicer day, I could've made it between Superchargers without stopping, but it did show a real need for DC fast charging between Little Rock, AR, and Springfield, MO.
Screenshot_20221029-213650.jpg


I made this leg of the trip between Branson and Springfield, Missouri, with the car indicating I'd get there with 1% SoC. I drove 60mph the whole way (in a 65mph zone) and ended up arriving with 5% SoC.
PXL_20221029_222424725.jpg


Our new pup getting her first ride in an EV.
PXL_20221029_212432134.MP.jpg


I'll try to post another update at 40,000 miles. We should be deep into cold weather by then, so my efficiency will be taking a hit.
 
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Dave EV

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Jun 23, 2009
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35,000 mile (56,000 km) update for my Sep 2021 SR+ LFP. The car is now 14 months old and was originally rated at 253 miles on a full charge. The Tessie app shows a battery capacity of 52.5 kWh (down 3.8% from my original 23 Oct 2021 post of 54.6 kWh), and a max range of 243 miles (down 4.0% from my original range of 253 miles). I've had Tessie since my first day or two or ownership, so this data shows the entire life of the car.
Screenshot_20221101-204344.jpg
Pretty cool how you can see the rate of capacity loss tapering down. Looks like it should largely stabilize around 10% capacity loss as the rate of calendar life loss stabilizes.

The LFP is a great battery for your usage pattern with the heavy duty cycles you are putting it under.

I think the LFP cars are capable of 32A L2 charging? Faster L2 charging combined with a later charge start time should help reduce rate of capacity loss by keeping the average charge rate lower. There have been studies that confirm this, though the ones I've seen were comparing L1 to L2 charging.
 
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Pretty cool how you can see the rate of capacity loss tapering down. Looks like it should largely stabilize around 10% capacity loss as the rate of calendar life loss stabilizes.

The LFP is a great battery for your usage pattern with the heavy duty cycles you are putting it under.

I think the LFP cars are capable of 32A L2 charging? Faster L2 charging combined with a later charge start time should help reduce rate of capacity loss by keeping the average charge rate lower. There have been studies that confirm this, though the ones I've seen were comparing L1 to L2 charging.
32a it is.
 
Pretty cool how you can see the rate of capacity loss tapering down. Looks like it should largely stabilize around 10% capacity loss as the rate of calendar life loss stabilizes.

The LFP is a great battery for your usage pattern with the heavy duty cycles you are putting it under.

I think the LFP cars are capable of 32A L2 charging? Faster L2 charging combined with a later charge start time should help reduce rate of capacity loss by keeping the average charge rate lower. There have been studies that confirm this, though the ones I've seen were comparing L1 to L2 charging.
Yeah, I used to have my charger set to 32 amps, but it started throwing errors sometimes and would stop charging in the middle of the night. I tried a lot of things to fix it, but ultimately what solved the problem was to lower the amps. Ever since I did that, I have had zero issues. So I'm guessing my circuit was being pushed a bit too much at 32 amps.
 
Yeah, I used to have my charger set to 32 amps, but it started throwing errors sometimes and would stop charging in the middle of the night. I tried a lot of things to fix it, but ultimately what solved the problem was to lower the amps. Ever since I did that, I have had zero issues. So I'm guessing my circuit was being pushed a bit too much at 32 amps.
If your EVSE is plugged into a 14-50 or 6-50 outlet, check if the outlet has full size brass contacts to the plug blades.

There are some common outlets where the contacts are steel and contact only half of the plug blades (this is visible by looking into the holes after removing the plug). This increases resistance and heat generation; many have found that charging at 32A problematic with these outlets (the Tesla mobile connector may throw heat warnings in this case and reduce amperage to 16A).
 
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Dave EV

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Jun 23, 2009
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Earth
If your EVSE is plugged into a 14-50 or 6-50 outlet, check if the outlet has full size brass contacts to the plug blades.

There are some common outlets where the contacts are steel and contact only half of the plug blades (this is visible by looking into the holes after removing the plug). This increases resistance and heat generation; many have found that charging at 32A problematic with these outlets (the Tesla mobile connector may throw heat warnings in this case and reduce amperage to 16A).
Yep, definitely do a close inspection of everything from the breaker to the EVSE to look for heat in the circuit or evidence of overheating. There's no reason why you shouldn't be able to charge at 32A all day every day.
 
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If your EVSE is plugged into a 14-50 or 6-50 outlet, check if the outlet has full size brass contacts to the plug blades.

There are some common outlets where the contacts are steel and contact only half of the plug blades (this is visible by looking into the holes after removing the plug). This increases resistance and heat generation; many have found that charging at 32A problematic with these outlets (the Tesla mobile connector may throw heat warnings in this case and reduce amperage to 16A).
Thanks, I'll give it a look. Do you happen to know if there's a preferred 14-50 outlet? Mine is just something the electrician had in his truck.
 

Dave EV

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Jun 23, 2009
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Thanks, I'll give it a look. Do you happen to know if there's a preferred 14-50 outlet? Mine is just something the electrician had in his truck.
Hubbell or Bryant. Stay away from Leviton and similar cheap outlets, they can't handle the continuous duty cycles of EV charging.

 
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Thanks, I'll give it a look. Do you happen to know if there's a preferred 14-50 outlet? Mine is just something the electrician had in his truck.
14-50 outlet brand and modelPlug blade contactsWire connectionsGeneral rating
Hubbell 9450A, Bryant 9450FRFull size brassPlate clampGood, relatively easy to connect wires properly.
Many othersFull size brassScrew downAcceptable, connect wires carefully.
Leviton 279-S00Half size steelScrew downMarginal at ~30A due to excess heat at the plug.

Regarding the plug blade contacts, steel is less conductive than brass, and smaller contact means less conductivity. Both mean more resistance and heat generation, which can be problematic at higher amperages. Also, half size contacts may be more prone to getting misaligned after fewer plug insertion and removal cycles compared to full size contacts. Misalignment can reduce contact area, further increasing resistance and heat generation.

Note that the Leviton 279-S00 is very common. It is also a compact outlet that does not require an oversize outlet box. Some other outlets are larger and will require a larger box or box extension to be used if replacing a Leviton 279-S00.

The "master thread" about 14-50 outlets includes a lot of comments based on the cosmetic appearance, size, and weight of the Leviton 279-S00 that are not really relevant. The actual important difference is in post #60 of that thread, which has the following close up photo of the plug blade contacts of the Hubbell 9450A (top, full size brass) and Leviton 279-S00 (bottom, half size steel):
81de81d6-a971-4fb1-b571-1ff4f33b17e8-jpeg.481431
 
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My 2022 60kWh LFP Model 3 was delivered 1 year ago today, making it one of the oldest 60kWh LFP cars in the fleet. Here is where we stand:

100% charge shows 265 miles (is this degradation or BMS calibration error? who knows, but it is small so who cares)
14,286 miles driven
Charged roughly once a week to 100% (L2 at home), and driven to about 20% remaining
All driving local except for 2 road trips:
1) San Jose to Reno (about 500 miles round trip, two short supper charger sessions)
1) San Jose to Dallas, Tx (3,644 miles round trip, all supper chargers)

Lifetime average is 230 Wh/mile, which includes the high speed Texas trip (average speed was over 90mph, with 272 Wh/mile trip average)
Average since returning from Texas trip is 213 Wh/mile (2625 miles)

Overall I'm very pleased and amazed at the efficiency of this car. It sees daily freeway use, I tend to be a "fast" driver, and yet my consumption figures are very low. I do run the tires near max psi, use the aero wheel covers, and have the unplugged performance front lip on the car, as well as tinting to reduce AC load. But I can't imagine all those things make more than a small change to the car's overall efficiency.

PXL_20221113_211516491 - Copy.jpg
 
20,000km update:
M3 RWD LFP batteries , 20,000Km in 6 months , 100% range at 431/430 kms.
I did a road trip from the west coast to Newfoundland and back with a new model 3 lfp. Lots of supercharging along the way. The car now has 20000km and gets the same 430km on a full charge. During the trip it very quickly dropped to 434km full charge and then reduced much more slowly.
 
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With the transition of some models to LFP battery chemistry and Tesla’s recommendation it regularly be charged to 100% I think the widespread perception in videos and literature, is that the LFP batteries suffer less degradation over time because charging to 100% with the other chemistries harms battery longevity.

It’s now starting to be known that 100% charging of your LFP batteries does as much if not slightly MORE harm to LFP batteries as it does to nickel based one’s, but Tesla recommends 100% charging of them ONLY because the BMS cannot accurately assess battery percentage and range unless the battery gets maxed out regularly. The explanation is that there is a much smaller difference in voltage from full to min charge for LFP than for Nickel based batteries, and LFP needs to maximize that voltage difference in order to precisely know where in the charge curve the battery sits.

LFP battery histories are now showing much greater battery degradation than nickel based owing they say, to these recommendations that they always be charged to 100% even though mounting evidence shows LFP battery chemistry is equally as vulnerable to battery degradation as any other variety of cell thru repeated max charging.

I mentioned this to friend with an LFP equipped Tesla and he was none too pleased; Saying often his pack was better and more robust than mine because he was told it NEEDED to be fully charged all the time…

They do mention about LFP battery cells “lasting longer”, but if with moderate care, Nickel cells can go close to 300,000 miles with less than 10% degradation is this a large issue?
 
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"It’s now starting to be known that 100% charging of your LFP batteries does as much if not slightly MORE harm to LFP batteries as it does to nickel based one’s, but Tesla recommends 100% charging of them ONLY because the BMS cannot accurately assess battery percentage and range unless the battery gets maxed out regularly. The explanation is that there is a much smaller difference in voltage from full to min charge for LFP than for Nickel based batteries, and LFP needs to maximize that voltage difference in order to precisely know where in the charge curve the battery sits.

LFP battery histories are now showing much greater battery degradation than nickel based owing they say, to these recommendations that they always be charged to 100% even though mounting evidence shows LFP battery chemistry is equally as vulnerable to battery degradation as any other variety of cell thru repeated max charging."



Citation to this info please...
 
Interesting, you have some source for that?
I really would like to keep our battery in good condition.
I found the actual research white paper comparing LFP with Nickel chemistry cells (and others) degradation vs max cycling, but now I can find the link! Still searching… Here is what led me to search…


 
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