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Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

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On the weekends when I am home I use the extra power from my solar panels to charge my car. Other then that you have to watch the time of day you charge depending on your electric rates.
When the sun is shining and the panels are providing power, how many amps do you have yours charging at?
For example, if your panels are only producing 20a worth of power and your are pulling 30a, you would be pulling from the grid ,yes?

I know I need to convert to watts/KWh but you get what I’m asking?

And yes, no charging between 4pm-9pm
 
When the sun is shining and the panels are providing power, how many amps do you have yours charging at?
For example, if your panels are only producing 20a worth of power and your are pulling 30a, you would be pulling from the grid ,yes?

I know I need to convert to watts/KWh but you get what I’m asking?

And yes, no charging between 4pm-9pm
Everybody's situation is going to be different! I have only had my solar for 2 months and the max I could set my charge to so far is 12 amps so it does not pull from the grid. I recently installed an Emporia Energy charger to go with their whole home energy monitoring device I have and it is supposed to be able to charge the car using the excess solar on its own but is not working 100% and they are looking into the issue. Before I got the charger I would have to change the rate of charge in the Tesla app throughout the day to set what I was able to draw only using the solar.
 
Hey all,

I currently have a 2021 M3 LR with approx 3600 miles and have software version 2021.36.8.8

I have noticed since this updated approx 2 weeks ago that my battery is always 3 percent lower than than what I'm asking for. I.e I wanted it charged to 60% and I have been waking up with 57%. I just got TeslaFi to log the data.
Screen Shot 2021-12-10 at 08.05.56.png


Can anyone tell me why this is happening?

Thank you all
 
IF you read around on the battery forum you'll eventually learn that the percentage displayed is just an estimate. It's impossible for the battery management system to be exact on its approximation of kWh of energy in the battery. The car charges to your set percentage and then goes to sleep. Sometimes when it'S sleeping the BMS will readjust its estimate of overall battery capacity, which in turn might affect how full the BMS thinks the battery is. I sometimes come back to a car that's 3% over what I specified, and it's the same reason.
Second, your battery is probably warm when you arrive home and charge, and it cools down (to around 49F in your example) slowly overnight. In the morning, with a cooler battery, there might be slightly less energy available to pull out of it. Not enough of a reduction to show the snowflake icon but still.
So, I see those two reasons are potential explanations for what you are seeing. No need for alarm, all is normal.
 
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This has been said/posted a lot of times by me. I guess some is about to get tired of seeing the same graph. ;)

[snip]

If you look at this graph( taken from a research report), 9.6 months at 25C causes a capacity loss of about 5% for a SOC of 60% or more. This graph should be read as *The time my car spends at a given SOC*, or average SOC when the car isnt in use.

There’s a sharp step at 55 to 60% where calendar aging increases much. Staying below this literally cut the calendar aging in half( at least).

View attachment 738269
Theres one thing more that is good with low SOC: the lower a cycle is in the SOC range, the lower the cyclic aging is. From research we know that a small cycle around 70% causes five times higher degradation than the same size of cycle at 30% (600 Full Equivalent Cycles) caused 10% degradation when cycled around 70% but only 2% when cycled around 30%. The battery can do five times more miles if cycled at low SOC than at high SOC. And still use the same size of the cycle, so the only thing changed is were in the SOC range it takes place.
This still counts for a quite small part of the total degradation so it isnt the main reason to stay at low SOC when possible.

Hey there - love the chart and explanations.

Two questions -

1. Do driving patterns have any substantial impact on battery life over the miles? for example, a higher C-Rate discharge should age Lithium faster, but not sure if frequent hard acceleration from 0-80 or whatever actually matters statistically? (on a LR AWD Boost, 40mph-80mph might hit 4C for example)

2. There's an article (Below) from Battery University that seems to indicate that while keeping voltage down to around 3.92V is good to reduce electrolyte oxidation (EO), going too far below 3.92V starts increasing another type of capacity loss due to "Growth of solid electrolyte interface" (SEI). Shouldn't we see a tick up on the low end for the storage test if this is the case? i.e. maybe 30-55% is the sweet spot for longevity, but 5-10% should be worse than 30-55%?

Source for #2: BU-808b: What Causes Li-ion to Die?

Thanks!
 
Hey there - love the chart and explanations.

Two questions -

1. Do driving patterns have any substantial impact on battery life over the miles? for example, a higher C-Rate discharge should age Lithium faster, but not sure if frequent hard acceleration from 0-80 or whatever actually matters statistically? (on a LR AWD Boost, 40mph-80mph might hit 4C for example)

2. There's an article (Below) from Battery University that seems to indicate that while keeping voltage down to around 3.92V is good to reduce electrolyte oxidation (EO), going too far below 3.92V starts increasing another type of capacity loss due to "Growth of solid electrolyte interface" (SEI). Shouldn't we see a tick up on the low end for the storage test if this is the case? i.e. maybe 30-55% is the sweet spot for longevity, but 5-10% should be worse than 30-55%?

Source for #2: BU-808b: What Causes Li-ion to Die?

Thanks!
1) Within normal limits, not very much. If you would discharge the whole cycle at 4C, then the cyclic wear will be higher and the battery life shorter. But short bursts of 10-20s will be a very little part of a full 4C cycle. 4C means emptying the battery in 15 minutes, thats 900s. So you would need about 90 full thottle runs 0-200km/h or 0-120mph with a model 3P to equal one 4C discharge cycle. (Just using mental arithmetic with a simplyfied 4C = full throttle to create an example so it is not an exact calculation). So after 900 quarter mile runs, it equals about 10 4C discharge cycles. The wear from this is not very high.
Of course, it could be possible to reduce the degradation further, but most probably it will not be measurable by the BMS by always driving very gently.
—> I have done the opposite. I didnt buy a 3 Performance to loiter around and I like acceleration very much. The stock summer wheels need a replacement soon and I had to switch front and rear tyres quite early in the summer as the rear tyres did show quite much wear. I have used the power with full power accelerations, but mostlty 0-120km/h as it weakens quite much with speed(I need a Plaid…)
My car will be one year since I got it in three weeks and it has 30.000km on the ODO. The Nominal full pack is at 81.1-81.2 kWh at the moment and it actually was lower a couple of days after delivery when I connected the Scan My Tesla-things. The range is somewhere very close to full ”new” range. Teslafi reports still over 500km range, so I havent really seen any decline in range, capacity or clear signs of degradation. My own calculation says that I should have a theoreticall degradation about 2.5% by now, most part from calendar aging(about 2%, and about 0.5% from cyclic aging. I think my BMS is slightly off, due to my daily 55% charging.

2) I havent read that article very thoroughly(just a very quick scan) but I did get the same question recently I think, and I answered that q here: SEI. If the article says that low SOC or charges is bad for the the battery, it is most certainly not right on that point.(There seem to be very many misconceptions about lithium batteries in many places. We need a reference to that statement).

SEI is not possible to avoid. Actually the initial SEI layer act as a protection. From all I learned and read SEI is the main degradation factor and most degradation you see is from SEI. If we can read some >100 research reports that show us that small cycles at low SOC is very best way to mitigate cyclic degradation, and most degradation comes from SEI the direct conclusion is that SEI doesnt come from low SOC or small cycles.
 
Hey there - love the chart and explanations.

Two questions -

1. Do driving patterns have any substantial impact on battery life over the miles? for example, a higher C-Rate discharge should age Lithium faster, but not sure if frequent hard acceleration from 0-80 or whatever actually matters statistically? (on a LR AWD Boost, 40mph-80mph might hit 4C for example)

2. There's an article (Below) from Battery University that seems to indicate that while keeping voltage down to around 3.92V is good to reduce electrolyte oxidation (EO), going too far below 3.92V starts increasing another type of capacity loss due to "Growth of solid electrolyte interface" (SEI). Shouldn't we see a tick up on the low end for the storage test if this is the case? i.e. maybe 30-55% is the sweet spot for longevity, but 5-10% should be worse than 30-55%?

Source for #2: BU-808b: What Causes Li-ion to Die?

Thanks!
by default 2021-12-10 at 6.27.53 PM.jpg

From a different article that made the same point, I decided to charge up to 60% SOC at home; but I do charge higher when necessary, like today; went skiing had to charge up to 80%, then 75% at the Supercharger. So far, it works for me.
 
View attachment 742932
From a different article that made the same point, I decided to charge up to 60% SOC at home; but I do charge higher when necessary, like today; went skiing had to charge up to 80%, then 75% at the Supercharger. So far, it works for me.
It's all about time spent at SOC - if you don't spend much time above 55% SOC, it's not a big deal. If you need the range, charge it up as high as you need, just try to discharge it below 55% sooner. Based on @AAKEE's previously posted data, it seems that 55% should be noticeably better than 60% as there appears to be a bit of a step function between 55-60%.

All that said - with Maine's cool temperatures, it probably doesn't make that much of a difference.
 
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It's all about time spent at SOC - if you don't spend much time above 55% SOC, it's not a big deal. If you need the range, charge it up as high as you need, just try to discharge it below 55% sooner. Based on @AAKEE's previously posted data, it seems that 55% should be noticeably better than 60% as there appears to be a bit of a step function between 55-60%.

All that said - with Maine's cool temperatures, it probably doesn't make that much of a difference.
Yep, no doubt, but since I started with 60% back in Summer 2019, as an experiment, I thought I should keep it going.
 
So I picked up my new M3LR 2 weeks ago from Bristol UK. Went through the whole 'new Tesla' check list thoroughly and only problem was that the sat nav did not appear to be working (giving car location at Tesla HQ in San Francisco). I reported this and was told "it can take 10 miles or so driving to pick up location", so (perhaps naively!) I took their word for it and started driving home. Got home sat nav still not locating properly. Called CS, they reset the car remotely, said it would be fine next time I drove. It wasn't. Called CS again, they asked me to do reset, power down, drive car 10 miles etc etc. No good. Did a software update, no good. Called CS again, was put through to someone (who actually knew something about software this time; in the Netherlands apparently) who said they'd found 2 missing files and could I drive around my work car-park for a few minutes while they fixed it. That didn't work (recurring theme) so they asked me to book into a service center (there are no mobile service vans where I live apparently). It looks like it's hardware related and I've got an 80 mile trip to look forward to (in 2 weeks time' earliest they could get me in) for rectification works.
It's no fun having a car with no sat nav; as well as having to use my phone for routing, the time is wrong so I can't use it to schedule off peak charging and (I suppose also because the time is wrong) the mirrors dip at the wrong times so I get dazzled at night. Now what you expect from a 50 grand car. My question to the forum is should I ask for any compensation for a month of hassle and inconvenience or is this just the 'norm' Tesla ownership experience (it's my first!). Cheers.
 
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Hi

With a Model 3 SR+...expect maybe something less than the 420 km but Im getting less than 250km

This is ananlysis of my last drives using tezla and note the poor efficiency and the massive use of E in Idle

I dont drive particularly fast or accelerate madly

Any ideas????

tesla.jpg
 
I know there are other threads with this topic however, I wanted to highlight another battery issue. One year anniversary with my 2021 M3P, and I've now noticed that my 100% battery capacity is 285 miles. This is an approximate 10% loss from the Tesla claimed 315-mile range. My daily charging is 80-90%, and after 18000 miles in one year I use 40-50% on average per day. Now, I don't believe this car ever had the Tesla advertised 315, to begin with, but there is a substantial loss after one year. I wanted to share this with others with the same battery to take notice and to hear others that might have the same issue. Mobile service is set for Friday, December 12th. I will update afterward.
 
Do you know that you have *actually* lost 10% of your range (i.e have you charged to a reference SOC and drove a reference distance/route and SOC drops more than it did a year ago), or are you basing this solely on the (now likely more accurate - or less inaccurate) range estimate?
 
Do you know that you have *actually* lost 10% of your range (i.e have you charged to a reference SOC and drove a reference distance/route and SOC drops more than it did a year ago), or are you basing this solely on the (now likely more accurate - or less inaccurate) range estimate?
I have not driven a set distance to compare, I will do it though thanks. I am basing this solely off of range estimates and percentages.