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

Doing a 226 mile (round-trip) drive in a SR+ (refreshed) and hoping to get there and back, but the car predicts just one way is going to use 59% of the battery. So expecting to need a bit of supercharge on the way. But UK prices are £0.48/kWh now so minimising this by doing a 100% charge for the very first time! Highest I'd gone before was 97%
Feels weird - pushing it to 100%! Do others do 100% charge as rarely as this? Note, I only do 4000 miles a year and most of my journeys are 4-20 miles with the occasional 150 miles to see parents. I've also got solar so I can keep it between 50 and 80%. Highest I've ever charged before was 97%.
 
So, I saved my father's day gas money and decided to join the cool kids by getting a OBD adapter, a BT dongle and SMT to satisfy my curiosity.
There's a lot of data and it's mostly gibberish to me, but it seems my battery is still showing 77.0kWh out of 77.8kWh when "new". Anything else to look at?
View attachment 819395
can you send us the link to buy those items. TIA
 

Hiline

Member
Supporting Member
Apr 16, 2022
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884
Los Angeles
Its not a loss at all, rather an incorrect estimate of the number of miles remaining in the battery. The number was never really accurate anyways because your actual energy usage per mile varies.

So if your have better battery health because you charged to 80% each day, then you will be able to drive farther ex. true range. Charging to 100% a few times should help the computer figure out the "estimated range" but does nothing for the battery.



The battery is "damaged" each time you use it, just a little bit. There is no scenario where you can ruin the battery by "going to 0" or something like that, because 0 is not really 0.

The 2 senarios that damage the battery:

1) Depth of discharge: take the amount that you discharge the battery before charging it again, and assume that it is worse go to have 1 cycle of 40% than 2 cycles of 20% even though you both times used 40%. Even if you charge correctly (as much as possible) you still accumulate damage from use.

2) Overcharging. Overcharging is counter-intuitive. The battery does not have a real 100% - the 100% is pushing the limits of the battery to the max and the battery is damaged by being in this state for a long time. So think of 90% as the real max, and 100% is 110%. Tesla could probably charge well past 100%, to the point where it would eventually explode. 100% is just the number they deem safe, but it does a lot of damage over a long time sitting in that state. In the reverse, the less the battery is charged as a total percent, the better off it is. Not exponentially, but 50 is better than 60 by a tiny amount.

This is very informative! I didn’t know you were supposed to charge less each time. Will try to get more frequent charging to reduce the amount of each charge.
 

SCTes1aMan

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Supporting Member
Mar 22, 2022
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1,557
Myrtle Beach, SC
Depth of discharge - the amount of energy removed and then added to a battery compared to its capacity. 100% to 0% and back again is one cycle, but is also a 100% depth of discharge. 75% to 25% and back again twice is also one cycle, but with a 50% depth of discharge. 50% to 40% and back again 10 times is one cycle but with a 10% depth of discharge. But the total number of cycles (i.e. the amount of useful energy you can get out of the battery) before it degrades to a certain point is inversely proportional to the depth of discharge (see Table 2), roughly tripling every time the average depth of discharge is cut in half, as well as inversely proportional to the upper voltage you were using when you were cycling the battery (see Table 4 in the previous link), where every 10-15% reduction also doubles the number of useful cycles you get. Calendar aging (aging associated with the battery simply existing over a certain amount of time, even if it is not used at all) is inversely proportional to the state of charge at which the battery is kept. High temperatures are bad for batteries in storage, but are beneficial when fast charging because they make it where the ions can more easily move around.

Put it all together and for maximum battery life, you want to:
1. Charge as often as possible (minimize average depth of discharge)
2. Put as little charge into the battery as you can get away with (minimize upper voltage)
3. Charge the battery as close to your departure time as possible and drive the car immediately after you charge it (minimize calendar aging)
I had no idea charging 10% each time prolongs battery life by 10x over charging 60% each time. Blows my mind.
 
🦄

You are well above the 76kWh degradation threshold still. It’s a shame we’ll never know where you started.
I just fell to 76.2 nfp, on an 82.1 new pack. (2021,.13k miles a dozen supercharges and the last 5k miles sitting at 55% almost all the time), definitely lost the battery lottery. (Also I live in hot Arizona)
 
My Model 3 is a year old and has around 7,000 miles on it. It’s supposed to get 265 miles on a full charge, but it gets only between 241 and 246 at full charge. I don’t have the car set on pre-condition because I don’t leave the house at a regular schedule. Would pre-conditioning the battery help to increase the charge capacity?
 
First off, you seem to be implying that you're charging to 100% on a regular basis. This is inadvisable, at least on Teslas with the Panasonic NCA (nickel, cobalt, aluminum oxide) batteries, which Tesla was using on all US-made Model 3s until fairly recently. A bit under a year ago, Tesla began offering Model 3s with Chinese-made LFP (lithium iron phosphate) batteries instead, and these can reportedly be regularly charged to 100% without problems. (If I understand correctly, all SR+ Model 3s made in China have always used the LFP batteries.) If you've got an LFP battery, then charging to 100% should be OK; but if you have an NCA battery, you should charge to 80-90% on a daily basis and reserve 100% charges for rare occasions when you need that much charge, like road trips every few months or the procedure I'm about to describe....

241/265 = .909, so you're looking at 9.1% degradation in a year. That's a bit on the high side, although some degradation is expected in the first year -- maybe 3-5%.

This type of issue is often a result of battery management system (BMS) calculations based on incomplete data, rather than actual battery problems. This can often happen if you tend to favor shallow charge/discharge cycles -- say, charging to 90%, driving to 60%, and charging back to 90%. This type of usage is better for the battery than frequent deep discharges, but the BMS tends to get confused by it and mis-reports the range as being too low. If this is happening, then the fix is to charge to 100%, do a deep discharge (to 10% or lower), and then another full (100%) charge. This should give the BMS more data, and you should see your estimated range recover, at least partly. I've seen this effect myself on my own car. Sometimes it takes another charge or two after the initial deep discharge to see the range recover, in my experience. Since this type of charge/discharge cycle is unhealthy for the battery, you shouldn't do it very often. I've only done it twice on my 3-year-old Model 3.

Note that, if I'm right about the cause of your 9.1% "degradation," it's not real battery degradation, just a reporting issue. Thus, although I've said the full-charge/deep-discharge procedure can "fix" the problem, the problem isn't "real," in the sense that the batteries are probably fine. Thus, it might be worth just leaving it as-is, at least until you actually need to do a relatively deep discharge anyway (like on a road trip).
 
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First off, you seem to be implying that you're charging to 100% on a regular basis. This is inadvisable, at least on Teslas with the Panasonic NCA (nickel, cobalt, aluminum oxide) batteries, which Tesla was using on all US-made Model 3s until fairly recently. A bit under a year ago, Tesla began offering Model 3s with Chinese-made LFP (lithium iron phosphate) batteries instead, and these can reportedly be regularly charged to 100% without problems. (If I understand correctly, all SR+ Model 3s made in China have always used the LFP batteries.) If you've got an LFP battery, then charging to 100% should be OK; but if you have an NCA battery, you should charge to 80-90% on a daily basis and reserve 100% charges for rare occasions when you need that much charge, like road trips every few months or the procedure I'm about to describe....

241/265 = .909, so you're looking at 9.1% degradation in a year. That's a bit on the high side, although some degradation is expected in the first year -- maybe 3-5%.

This type of issue is often a result of battery management system (BMS) calculations based on incomplete data, rather than actual battery problems. This can often happen if you tend to favor shallow charge/discharge cycles -- say, charging to 90%, driving to 60%, and charging back to 90%. This type of usage is better for the battery than frequent deep discharges, but the BMS tends to get confused by it and mis-reports the range as being too low. If this is happening, then the fix is to charge to 100%, do a deep discharge (to 10% or lower), and then another full (100%) charge. This should give the BMS more data, and you should see your estimated range recover, at least partly. I've seen this effect myself on my own car. Sometimes it takes another charge or two after the initial deep discharge to see the range recover, in my experience. Since this type of charge/discharge cycle is unhealthy for the battery, you shouldn't do it very often. I've only done it twice on my 3-year-old Model 3.

Note that, if I'm right about the cause of your 9.1% "degradation," it's not real battery degradation, just a reporting issue. Thus, although I've said the full-charge/deep-discharge procedure can "fix" the problem, the problem isn't "real," in the sense that the batteries are probably fine. Thus, it might be worth just leaving it as-is, at least until you actually need to do a relatively deep discharge anyway (like on a road trip).
Thanks very much for a thorough analysis. I do charge my car daily at 90% on a regular basis but charged it to 100% just to see the full charge capacity. However, I do tend to drive short distances (30-50 miles) and have daily shallow charges. So hopefully the battery degradation is indeed resulted from a reporting issue. Thanks again.
 
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Thanks very much for a thorough analysis. I do charge my car daily at 90% on a regular basis but charged it to 100% just to see the full charge capacity. However, I do tend to drive short distances (30-50 miles) and have daily shallow charges. So hopefully the battery degradation is indeed resulted from a reporting issue. Thanks again.

IF you drive short distances then you might want to set your daily charge limit to be substantially lower. I set mine to the minimum at 50% after reading this thread.
 
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Hiline

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Apr 16, 2022
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884
Los Angeles
My Model 3 Long Range's lifetime efficiency is 4 miles per kWh (0.25 kWh per mile). With the battery capacity of 70 kWh, looks like I can get 280 miles out of a single full charge in theory, which is a far cry from the marketed 360-mile range which translates to less than 0.2 kWh per mile. I don't have AC turned on very often and rarely play music while driving. Display mode is Dark, Sentry Mode is Off.

So how do I get closer to 360 miles? Is 4 miles per kWh efficiency normal?
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
13,366
17,015
San Diego
Is 4 miles per kWh efficiency normal?
Yes.
So how do I get closer to 360 miles?
Drive more slowly and don’t stop until the battery is empty and the car stops moving.
a far cry from the marketed 360-mile range which translates to less than 0.2 kWh per mile.
It’s 353 miles (358 with a larger battery pack of “82.1kWh”) which means 220Wh/mi. Not less than 200Wh/mi.

This is achievable but it requires you to go slowly; probably about 40mph would be slow enough, though I have not calculated it.

The first Model 3 did over 600 miles on a charge but it required driving at ~19mph. Probably not possible on AWD due to extra losses, but 400-500 miles should be doable at 19mph. And of course you can’t stop or use the AC or heat or regen.

With the battery capacity of 70 kWh,
A new battery (not RWD or SR+) has a capacity of about 78kWh (minimum - higher for some models). Your battery may be at 70kWh. But obviously that would reduce your rated range if they tested that aged vehicle.
 
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Bouba

Active Member
Sep 23, 2021
1,253
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France
My Model 3 Long Range's lifetime efficiency is 4 miles per kWh (0.25 kWh per mile). With the battery capacity of 70 kWh, looks like I can get 280 miles out of a single full charge in theory, which is a far cry from the marketed 360-mile range which translates to less than 0.2 kWh per mile. I don't have AC turned on very often and rarely play music while driving. Display mode is Dark, Sentry Mode is Off.

So how do I get closer to 360 miles? Is 4 miles per kWh efficiency normal?
360 miles is too high for 70 kWh ....75 kWh is less than 340....The M3LR is incredibly efficient but the air con, heater and short journeys are range killers...uphill is no problem, as long as you also go down the same hill
 
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Hiline

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Apr 16, 2022
635
884
Los Angeles
Yes.

Drive more slowly and don’t stop until the battery is empty and the car stops moving.

It’s 353 miles (358 with a larger battery pack of “82.1kWh”) which means 220Wh/mi. Not less than 200Wh/mi.

This is achievable but it requires you to go slowly; probably about 40mph would be slow enough, though I have not calculated it.

The first Model 3 did over 600 miles on a charge but it required driving at ~19mph. Probably not possible on AWD due to extra losses, but 400-500 miles should be doable at 19mph. And of course you can’t stop or use the AC or heat or regen.


A new battery (not RWD or SR+) has a capacity of about 78kWh (minimum - higher for some models). Your battery may be at 70kWh. But obviously that would reduce your rated range if they tested that aged vehicle.

360 miles is too high for 70 kWh ....75 kWh is less than 340....The M3LR is incredibly efficient but the air con, heater and short journeys are range killers...uphill is no problem, as long as you also go down the same hill
Thank you both for the info! I have a Model 3LR 2022 ... what is the battery capacity of this? I read online that the M3LR battery capacity was 70 kWh but perhaps newer units have a different battery size.

If 4 miles/kWh is the standard then I guess I don't necessarily need to do anything differently ...
 

Bouba

Active Member
Sep 23, 2021
1,253
1,121
France
Thank you both for the info! I have a Model 3LR 2022 ... what is the battery capacity of this? I read online that the M3LR battery capacity was 70 kWh but perhaps newer units have a different battery size.

If 4 miles/kWh is the standard then I guess I don't necessarily need to do anything differently ...
About 82kwh if you want to drive till it stops
 
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Update 1: 416 miles after the battery cycle count reset from service with one supercharge and two 4+ hour level 2 charges later -- estimated battery at 100% is 308.53 mile range right now. Charged to 90% today on level 2. Car slept for 20 minutes after charging. Upon getting in the car SOC had moved up to 93%. Not sure why my SOC changes so much...it changes +/- 2-3% lately while stationary.

Update 2: Another 10 days and 607 miles with battery drained down to 30% and another Supercharge and few L2 charges later, 100% estimated range is 300 miles.
 

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