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

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I am goinn to follow Tesla recommendation to charge LFP to 100% at least once a week. Works for my commute routine.
Another question : I have a 15-20 in my garage which charges my model 3 at 7-8 miles / hr currently, giving me ~60 miles overnight. On some old forum I saw that 6-20 NEMA plug can charge at 15 miles /hr. Does anyone use 6-20? Form the forums seems like it is easier and cheaper to convert a 15-20 to 6-20. Is my understanding right?

Yes, it's possible and a pretty good solution if there is nothing else on that circuit (since you're converting the whole thing to 240v). See discussion here:

 
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I think it adjusts to the consumption data.
The estimates of the BMS vary and it’s likely hard especially with LFP for them to tune things exactly.

There’s never been any strong evidence that range adjusts based on usage. I am sure there is some dependence, but it is entirely possible that higher consumption values lead to higher range, and vice versa (just as likely as the opposite dependence). It all just depends on the BMS estimation and how the algorithm works. At some point it has to look at voltages, voltages under load, measures integrated current*voltage, etc., and comes up with an estimate. Clearly exact usage patterns will affect these estimates just because it changes the operating point inputs to the estimation. But the relationship is very unclear.

I’d expect some adjustments to the algorithms going forward as they learn how to tweak the estimate to be more accurate.

Also temperature can affect the estimate and they may not be fully accounting for errors that may introduce in the estimate.

It’s all very complicated and it’s impressive that it is usually accurate within a couple % (as it needs to be, to avoid unpleasant surprises). None of this weird stuff that happens with phones with aged batteries sometimes where the % drops from 60% to 5% when the battery gets cold…
 
This is really helpful to me because I went on a second trip recently, and again lost ground on my range, which dropped back down from typically 252 to now 249. This has been the case for 8 or 9 days now so I’m losing hope that I will wake up tomorrow, like USBSeawolf2000, back at 251-252 range.

Car now has about 2500 miles on it, and on both trips I have supercharged it to 100% at least once during the trip. Otherwise just level 1 charging to 100% every day. There have only been a handful of days in the past 3 months when the car’s state of charge dropped below 80%. The fact that you guys have seen drops even though you haven’t used superchargers indicates to me not to get too obsessed that I may have caused my drop with supercharging. FARKLE! shares the same climate as me, so maybe the drops are caused by temperature drop, though if that was the case, USBSeawolf2000 would have out-dropped us in his colder climate.

I guess it all comes back to not worrying too much about the projected range until the dropped miles really start accumulating…
 
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There is a thread in the model 3 section where someone recalibrated their BMS by allowing the car to sit at various states of charge (long enough for the car to "go to sleep" and disconnect the high voltage so the battery can float). It apparently took a few months, but they claim to have recovered much of their "lost range" via this process (it was an NCA car, though the same principle should apply to our LFP cars). I've only been plugging my car in to charge once or twice a week, and letting it sit the other nights at what ever state of charge it is at. I tend to use about 20% charge a day, so first night it sits around 80%, then 60%, then 40%. So far I've been charging it to 100% after that to avoid the discharge cycle going too deep. No idea if this is the ideal way to treat an LFP battery, but hopefully it should at least give the BMS a few calibration points.
 
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There is a thread in the model 3 section where someone recalibrated their BMS by allowing the car to sit at various states of charge (long enough for the car to "go to sleep" and disconnect the high voltage so the battery can float). It apparently took a few months, but they claim to have recovered much of their "lost range" via this process (it was an NCA car, though the same principle should apply to our LFP cars). I've only been plugging my car in to charge once or twice a week, and letting it sit the other nights at what ever state of charge it is at. I tend to use about 20% charge a day, so first night it sits around 80%, then 60%, then 40%. So far I've been charging it to 100% after that to avoid the discharge cycle going too deep. No idea if this is the ideal way to treat an LFP battery, but hopefully it should at least give the BMS a few calibration points.
Is it 2021 LFP or 2022 LFP ? Any loss of range so far for you? So looks like you are doing 100% at least twice per Week.
 
Is it 2021 LFP or 2022 LFP ? Any loss of range so far for you? So looks like you are doing 100% at least twice per Week.
2022 LFP. No loss of range when full, and I have 552 total miles and exactly 3 weeks of ownership this far. I think I've charged the car 4 times now, always to 100%.

A few interesting numbers...
Window sticker says 272 miles, and 25 kw-hr/100 miles (so 250 wh/mi). That would imply a 68kwh battery....which I'm pretty sure isn't the case. ABRP uses 244 Wh/mi for reference consumption at 65mph, and the "rated" consumption line on the energy graph appears to be around 224 wh/mi. (224 wh/mi x 272 miles = 60,928 wh, so pretty close). I'm assuming it is about a 60kwh + buffer battery, but I haven't seen anything definitive, so perhaps usable is closer to 61....

Full charge shows 272 miles beside the battery symbol. My average energy consumption bounces between 180 and 230 wh/mi, and indeed I see projected range numbers over 300 miles when the battery is full and my wh/mi is low.

But here is where it gets interesting....
I left Wednesday afternoon with a full charge and drove almost 50 miles - showing over 300 miles range when full. Made several stops, each 45 min to 1.5 hours long, before returning home. Sentry mode was on when I was out, but not at home. Did not plug in at home.
Did the same thing Thursday and Friday, though mileage was slightly less. Here we are Friday night and I show the following since last charge:
123.3 miles traveled, 213 wh/mi average, 26 kwh consumed, but only 47% of the battery left, and my projected range (based on 221 wh/mi at the moment) is 129 miles. That's 252 miles total range, and implies 55kwh of total battery available, or that over 5kwh of battery has been lost due to vampire drain.
 
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2022 LFP. No loss of range when full, and I have 552 total miles and exactly 3 weeks of ownership this far. I think I've charged the car 4 times now, always to 100%.

A few interesting numbers...
Window sticker says 272 miles, and 25 kw-hr/100 miles (so 250 wh/mi). That would imply a 68kwh battery....which I'm pretty sure isn't the case. ABRP uses 244 Wh/mi for reference consumption at 65mph, and the "rated" consumption line on the energy graph appears to be around 224 wh/mi. (224 wh/mi x 272 miles = 60,928 wh, so pretty close). I'm assuming it is about a 60kwh + buffer battery, but I haven't seen anything definitive, so perhaps usable is closer to 61....

Full charge shows 272 miles beside the battery symbol. My average energy consumption bounces between 180 and 230 wh/mi, and indeed I see projected range numbers over 300 miles when the battery is full and my wh/mi is low.

But here is where it gets interesting....
I left Wednesday afternoon with a full charge and drove almost 50 miles - showing over 300 miles range when full. Made several stops, each 45 min to 1.5 hours long, before returning home. Sentry mode was on when I was out, but not at home. Did not plug in at home.
Did the same thing Thursday and Friday, though mileage was slightly less. Here we are Friday night and I show the following since last charge:
123.3 miles traveled, 213 wh/mi average, 26 kwh consumed, but only 47% of the battery left, and my projected range (based on 221 wh/mi at the moment) is 129 miles. That's 252 miles total range, and implies 55kwh of total battery available, or that over 5kwh of battery has been lost due to vampire drain.
Thanks for sharing your experience with LFP. I am gathering all the information i can to get ready how to go about charging my car when it arrives. Woùld love to know more about cold weather range loss and if you have charge every 2 days in colder days vs 3 to 4 days . Not sure how low temps go down there but would be interesting to see.
 
There is a thread in the model 3 section where someone recalibrated their BMS by allowing the car to sit at various states of charge (long enough for the car to "go to sleep" and disconnect the high voltage so the battery can float).

A not normal situation. It happens but is not the norm unless your car never sleeps.


25 kw-hr/100

Wall to wheels.

consumption line on the energy graph appears to be around 224 wh/mi.

So the constant is about 5Wh/mi less than that or 220-221Wh/mi. (My guess is the line is at 225Wh/mi or 226Wh/mi but I could be wrong.)

Implies 220Wh/mi*272mi = ~60kWh degradation threshold.

I'm assuming it is about a 60kwh + buffer battery, but I haven't seen anything definitive, so perhaps usable is closer to 61....

Didn’t we do those calculations here already for a 60kWh? The 60kWh includes the buffer, to be clear. Actually data is from your car. It’s well established that the methods work - they are definitive. Here’s a capture from a European RWD in any case (confirms the method), and the post below that includes links to data from your car (thanks again!):

MASTER THREAD: 2021 Model 3 - Charge data, battery discussion etc

123.3 miles traveled, 213 wh/mi average, 26 kwh consumed, but only 47% of the battery left, and my projected range (based on 221 wh/mi at the moment) is 129 miles

Projected range times consumption not at 100% results in a number “remaining” that includes only a portion of the buffer (half in this case, so about 1.4kWh) - even though it all exists still in your pack. So that leads to error with your math.

But yeah you seem to have lost about:

0.955*220Wh/mi*0.53*272mi - 123.3mi*213Wh/mi = 4kWh

to vampire/feature drain over a couple days. Not too abnormal. Very approximate since your numbers are with % so there is potentially error. Could be less than 4kWh.
 
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Thanks for sharing your experience with LFP. I am gathering all the information i can to get ready how to go about charging my car when it arrives. Woùld love to know more about cold weather range loss and if you have charge every 2 days in colder days vs 3 to 4 days . Not sure how low temps go down there but would be interesting to see.
I live in San Jose, CA....while it sometimes "feels" cold here (~40F and humid), I don't think you would call anything we get here cold (it's still hot according to my dogs, LoL). Out of curiosity I looked up the all time lows here...had to go back to 1990 to find anything "significantly" below freezing...and that was only -7C (19F)....so still probably not cold in your book. But I'll be sure to report any temperature related range changes I happen to notice.
 
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I live in San Jose, CA....while it sometimes "feels" cold here (~40F and humid), I don't think you would call anything we get here cold (it's still hot according to my dogs, LoL). Out of curiosity I looked up the all time lows here...had to go back to 1990 to find anything "significantly" below freezing...and that was only -7C (19F)....so still probably not cold in your book. But I'll be sure to report any temperature related range changes I happen to notice.

My impression after driving an electric motorcycle for a number of years is that just getting a little bit colder (as opposed to eastern Canada cold) had a measurable impact on performance. They were lithium batteries and I can’t remember the other chemicals they were using, and I’m sure that now, 10 or 15 years later, the LFP batteries in our cars are better at handling temperature drops. But it does seem logical that performance starts dropping to some smaller extent to go along with any kind of temperature drops, even before things get super cold.
 
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I've got a few thousand more miles before I post another degradation update, but I thought I'd share this in the meantime. This week I set my personal record for my most efficient commute yet in my 2021 Model 3 SR+ LFP. I managed 184 Wh/mile over my 111.4 mile commute (which has significant, long hills). My previous best was 188 Wh/mile. It was an unseasonably warm day when I got the 184, and averaged 52F on my way to work and 81F on my way home. So I barely had to use any HVAC during either leg (I precondition the cabin before I unplug in the morning, and then just use seat heater (and now heated steering wheel!) until my feet start to feel chilly).

Regarding degradation--I've definitely seen a minor drop in measured battery capacity since the weather started getting cool/cold. I'm still unsure if that's just normal, expected degradation, or if it'll reverse in the spring with warmer weather.

PXL_20211202_224232439.jpg
 
OK, so on 12/2 the SR+ was charged to 100% SOC. A trip meter was reset to 0, and a kWh counter was was placed between my car and the 120 volt charging outlet. Now, today, after charging to 100% SOC again, I have the following info from the trip meter and the kWh counter:

Miles drivenkWh used by carwatt hrs/milekWh put in car
85.12023731

Is it freaky-deaky that 3 kWh has to be put into the car for every 2 kWh it uses?
 
OK, so on 12/2 the SR+ was charged to 100% SOC. A trip meter was reset to 0, and a kWh counter was was placed between my car and the 120 volt charging outlet. Now, today, after charging to 100% SOC again, I have the following info from the trip meter and the kWh counter:

Miles drivenkWh used by carwatt hrs/milekWh put in car
85.12023731
Is it freaky-deaky that 3 kWh has to be put into the car for every 2 kWh it uses?

That's not the right way to look at it (though it's very real, and it does indicate some issues you may want to address if you care about efficiency). There's a baseline static consumption, so if you have low daily consumption it's going to look worse.

There's also charging inefficiency of about 25-30% loss when charging off of 120V (I'm assuming 12A). So that 31kWh only provides ~23kWh to the vehicle battery (so, something like 110 rated miles were added in your case, using the very approximate 206Wh/mi displayed rated miles "constant" (not the charging constant!) calculated previously from the 54.7kWh degradation threshold, but it may be a little lower in your case since your capacity may currently exceed the degradation threshold, and also the charging inefficiency estimate here will provide most of the error in this estimate).

So anyway that means you lost about 3kWh "unmetered" when parked for about 5 days. Or about 0.6kWh per day.

So if you'd driven 85 miles in one day instead, you'd have used 20kWh and wasted 0.6kWh, which is just 3% overhead (and the remaining 8kWh is charging overhead).

If you want better charging efficiency you should go to 240V/32A which will get you close to 88% efficient. So replenishing that 23kWh would have only taken 26kWh from the wall rather than 31kWh. (By the way even going to 240V/12A is a huge improvement in efficiency, so don't feel like going all the way to 32A is required to get close to the 88% efficient result. There are diminishing returns, but the curve of improvement is very steep when you're starting at 1.44kW charging.) Here's a decent rough model (though the best-case efficiency numbers are about 4.5% high - I think the energy added was overestimated for this model due to the buffer discrepancy). The actual efficiency is published by Tesla in their EPA documents and is very clearly best-case 88-89%.

All the efficiency ratings from the EPA are with the 240V/32A maximum rate charging for the vehicle.
 
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That's not the right way to look at it (though it's very real, and it does indicate some issues you may want to address if you care about efficiency). There's a baseline static consumption, so if you have low daily consumption it's going to look worse.

There's also charging inefficiency of about 25-30% loss when charging off of 120V (I'm assuming 12A). So that 31kWh only provides ~23kWh to the vehicle battery (so, something like 110 rated miles were added in your case, using the very approximate 206Wh/mi displayed rated miles "constant" (not the charging constant!) calculated previously from the 54.7kWh degradation threshold, but it may be a little lower in your case since your capacity may currently exceed the degradation threshold, and also the charging inefficiency estimate here will provide most of the error in this estimate).

So anyway that means you lost about 3kWh "unmetered" when parked for about 5 days. Or about 0.6kWh per day.

So if you'd driven 85 miles in one day instead, you'd have used 20kWh and wasted 0.6kWh, which is just 3% overhead (and the remaining 8kWh is charging overhead).

If you want better charging efficiency you should go to 240V/32A which will get you close to 88% efficient. So replenishing that 23kWh would have only taken 26kWh from the wall rather than 31kWh. (By the way even going to 240V/12A is a huge improvement in efficiency, so don't feel like going all the way to 32A is required to get close to the 88% efficient result. There are diminishing returns, but the curve of improvement is very steep when you're starting at 1.44kW charging.) Here's a decent rough model (though the best-case efficiency numbers are about 4.5% high - I think the energy added was overestimated for this model due to the buffer discrepancy). The actual efficiency is published by Tesla in their EPA documents and is very clearly best-case 88-89%.

All the efficiency ratings from the EPA are with the 240V/32A maximum rate charging for the vehicle.

Thanks AlanSubie4Life! Charging inefficiency and a bit of unmetered loss. Installing a standard charging system could take me from 70% to 88% charging efficiency. As well as give me more options as far as not charging for multiple days in a row. If I lost 5 kWh every 5 days it would be roughly losing a dollar every 5 days, or $75 per year. Thanks again for sharing this information.
 
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It was an unseasonably warm day when I got So I barely had to use any HVAC during either leg (I precondition the cabin before I unplug in the morning, and then just use seat heater (and now heated steering wheel!) until my feet start to feel chilly).
What do you mean by heated steering wheel on a 21' SR+? How? ( checked upgrades on Tesla app just in case)

Edit: Nevermind, just updated the app!!! Woo hoo toasty hands!
 
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Had a few charges to 100% since last reported. Car continues to report 251 miles instead of 252.

If I add the actual driven miles with the screen reported remaining miles, I get about 242 miles so the colder weather is taking some toll but way better than expected.

Heated steering wheel allowed me to commute this morning without turning on cabin heat and interior did not fog up. I felt toasty with heated seats and wheels.
 
Had a few charges to 100% since last reported. Car continues to report 251 miles instead of 252.

If I add the actual driven miles with the screen reported remaining miles, I get about 242 miles so the colder weather is taking some toll but way better than expected.

Heated steering wheel allowed me to commute this morning without turning on cabin heat and interior did not fog up. I felt toasty with heated seats and wheels.

From what I understand from @AAKEE, it is probably (he is not 100% sure on this latest version of LFP) detrimental to leave LFP batteries at 100%, for calendar aging. I understand the need to do it periodically for LFP, and I know Tesla does not limit or recommend against it. And I understand limited regen is nearly a non-issue on these packs (are you still finding that to be true in cooler weather near 100%?).

But it sounds like people are routinely doing it (rather than once a month or whatever), even if they don’t need the energy daily? Why?

I guess it will probably matter less than for NCA cells, but still…if I had one of these cars, and I was doing short daily trips, I’d daily charge (though deep cycles are apparently not an issue for LFP) it to 60-70% most of the time, and only occasionally bump it to 100%, to get the BMS estimate correct.

I say this as someone who frequently used 90% (there were reasons for it - free charging at work being one) as a charge level for my NCA, but after 10% capacity loss, I’ve changed to 60-70% daily level, with daily charging to ensure shallow cycles, because for NCA it seems like it can only help.

My guess is people who leave their LFP batteries at lower SOC most of the time will see generally better results long term (but there is going to be a distribution, and some people who do this might still have problems). Obviously if you need the full range, you just don’t worry about it and probably LFP will still do much better than NCA in that daily 100% to 0% use case.
 
OK, so on 12/2 the SR+ was charged to 100% SOC. A trip meter was reset to 0, and a kWh counter was was placed between my car and the 120 volt charging outlet. Now, today, after charging to 100% SOC again, I have the following info from the trip meter and the kWh counter:

Miles drivenkWh used by carwatt hrs/milekWh put in car
85.12023731

Is it freaky-deaky that 3 kWh has to be put into the car for every 2 kWh it uses?
Here is my last charge data for reference. I have Gen2 Tesla Wall Connector and charge at 245V @32 Amps. I set it to start at midnight so the voltage is higher.

Per my Sense Monitor, the charge consumed 42.9 kWh and took ~5.5 hours. It refilled 189 miles from 62 -> 251 miles. Therefore, the consumption from the main panel came out to 227 Wh/mi (42,900 Wh / 189 miles) which includes charging loss.

The car displayed 205 Wh/mi prior to the charge. So the charging loss with L2 is about 10% (205 vs 227).

This also means I got 148.5 MPGe (actual - 33,700/227) in the winter. I am doing great with LFP SR+.

1638983625567.png
 
From what I understand from @AAKEE, it is probably (he is not 100% sure on this latest version of LFP) detrimental to leave LFP batteries at 100%, for calendar aging. I understand the need to do it periodically for LFP, and I know Tesla does not limit or recommend against it. And I understand limited regen is nearly a non-issue on these packs (are you still finding that to be true in cooler weather near 100%?).

But it sounds like people are routinely doing it (rather than once a month or whatever), even if they don’t need the energy daily? Why?

I guess it will probably matter less than for NCA cells, but still…if I had one of these cars, and I was doing short daily trips, I’d daily charge (though deep cycles are apparently not an issue for LFP) it to 60-70% most of the time, and only occasionally bump it to 100%, to get the BMS estimate correct.

I say this as someone who frequently used 90% (there were reasons for it - free charging at work being one) as a charge level for my NCA, but after 10% capacity loss, I’ve changed to 60-70% daily level, with daily charging to ensure shallow cycles, because for NCA it seems like it can only help.

My guess is people who leave their LFP batteries at lower SOC most of the time will see generally better results long term (but there is going to be a distribution, and some people who do this might still have problems). Obviously if you need the full range, you just don’t worry about it and probably LFP will still do much better than NCA in that daily 100% to 0% use case.
I daily charge to 100%, and I'm now only getting 249 miles at 100%. It started declining from 253-254 around 2 weeks ago. 2400 miles on the odo. I'm going to stop daily charging to 100% and instead charge to 70% - 80% and see if there is any improvement. But yeah, I agree...most people probably don't need to charge to 100% every night.

Also, I have a mobile service appt tomorrow, will ask them if they've seen this decline on other LFPs around me.
 
And I understand limited regen is nearly a non-issue on these packs (are you still finding that to be true in cooler weather near 100%?).
I am attaching two captures. 99.4% SOC with 31kW regen and another one with 85% SOC with 12kW regen.

The difference was the battery pack temperatures, 62F vs 47F average temps. Since I timed the full charge before I leave home, I had 62F and after 8.5 hours parked, temp dropped from 66F (@work) to 47F (leaving work).

When I got home that day, pack temp was 55F with 22kW regen.
 

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