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

[Robert A]

New to Tesla and I'm trying to wrap my head around the miles remaining on the display at the top of the screen. I have a 2021 LR-AWD and have a few questions.

For reference, I charge at home to 90%. After the charge, the displayed range is typically 315 miles.

1) Is the displayed range supposed to adjust based on recent driving habits? Mine is always the same (when charged to 90%) no matter how I've been driving.

2) Recently, after driving 137 miles, the remaining range was 113 miles, implying that the range before driving those miles should have been 250, not 315 as was displayed. Okay, I get it -- the computer doesn't know how you're doing to drive, but shouldn't it adjust to your driving habits at some point? Then when I recharged that evening, the range shot right back up to 315, not 250. Is this expected behavior? Why?

3) At the same point in time as #2 above, the remaining battery charge was 32% (from 90%), representing a 58% use of battery charge. The "since last charge" displayed 34 kWh of use (and 244 Wh/mi). If the battery lost 34 kWh over the 58% consumption of it's capacity, this would imply that a 100% charge is 34 kWH /58% = 58.62 kWh battery capacity, not 75 kWh to 82 kWh as many people report. Does this make sense, and if so, why?

4) If my average driving habits are 244 Wh/mi, and usable battery capacity is actually 75 kWh, this would imply a total range of 307 miles, not the 250 miles or so that I'm achieving given that rate of consumption.

I know there are reasons for these behavior items that I don't understand. I'm hoping someone can explain it all.

FWIW, "sentry mode" is off, and I rarely wake the car up when it is parked.

 

[AAKEE]

1) Is the displayed range supposed to adjust based on recent driving habits? Mine is always the same (when charged to 90%) no matter how I've been driving.

Nope, it wont change(other after software updates, sometime). The range is close to the EPA test cycle, which means no heating or AC, no fast driving and also it inlcudes the battery buffer that you cannot use. It is a theoretical value of quite low value for you. Suggest using percentage of SOC instead.

2) Recently, after driving 137 miles, the remaining range was 113 miles, implying that the range before driving those miles should have been 250, not 315 as was displayed. Okay, I get it -- the computer doesn't know how you're doing to drive, but shouldn't it adjust to your driving habits at some point? Then when I recharged that evening, the range shot right back up to 315, not 250. Is this expected behavior? Why?

Answer 1 probably already gave you the answer for this: Its a theoretical value, hard to see in real life unless driving very gentle and slow with no use of AC or heating and also, you can not use the last 4.5% of the battery because it is the buffer to keep the battery health.
So driving might use 30% mor or so, wich means that for each 100 miles you go, the displayed range decrease 130miles. = less left just as per your calculation.

3) At the same point in time as #2 above, the remaining battery charge was 32% (from 90%), representing a 58% use of battery charge. The "since last charge" displayed 34 kWh of use (and 244 Wh/mi). If the battery lost 34 kWh over the 58% consumption of it's capacity, this would imply that a 100% charge is 34 kWH /58% = 58.62 kWh battery capacity, not 75 kWh to 82 kWh as many people report. Does this make sense, and if so, why?

Your LR probably have the 77.8kwh battery, not the 82kwh. And you have 4.5% buffer so at best you have 74.2kwh to use.
For me this numbers make sense in my car, each time. Did you preheat or park the car at any time before or during your 137miles drive ?
Whats done parked, doesnt show in kwh since last charge.
If I drive to work, and use 10%, and after thje day hoime, and use 13%(cold outside), total is 23% and it also reflects the numbers in kwh when charging(added kwh to the battery in an app). Charge value seen on the chargers meter is 8-10% more dure to losses.

If I preheat it might cost about 5-8% and it looks like your delta also, so I suspect that.

4) If my average driving habits are 244 Wh/mi, and usable battery capacity is actually 75 kWh, this would imply a total range of 307 miles, not the 250 miles or so that I'm achieving given that rate of consumption.
I know there are reasons for these behavior items that I don't understand. I'm hoping someone can explain it all.

Your usable capacity in max 77.8 -3.5(buffer) so about 74.3kwh if there is no battery degradation. Probably a bit less.

You can use the energy app to calculate the battery capacity: use consumtion on the left side and the range on the right side(from selection ”normal range”): multiply them.
And after this, divide the result with the state of charge displayed/100( so, 70% state of charge is 0.7).
The result is the total battery capacity the cars battery management system thinks the battery can hold, in Wh. Divide with 1000 and you have kwh. This is the total, including the 3.5kwh buffer you cannot use.

 

[Anders0_3]

Hi, I am new to the world of Tesla and have just taken ownership of the model three and working my way through the new world of driving electric cars so apologies if I am asking simple question or anything already covered.

Currently I am not driving very many miles and with the cold weather I have noticed that overnight the battery can drop by at least 5%. So my question is... would it be best to keep the car plugged with a charging cap of say 70%, i assume that if I put it on charge it will charge to 70% and then kick back in to stay at 70% ifit drops below Or leave it off charge and losing battery and just top up when needed?
The car came with a full charge and I have add 46wkh, I have done 120 miles and now have 30% battery, does this seem like high battery usage?

Which is the most cost effective way of running the car?

Thanks
Anders

 

[terrywhite]

Directly from the manual:


About the Battery

Model 3 has one of the most sophisticated battery systems in the world. The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it. This is particularly important if you are not planning to drive Model 3 for several weeks. When plugged in, Model 3 wakes up when needed to automatically maintain a charge level that maximizes the lifetime of the Battery.

NOTE: When left idle and unplugged, your vehicle periodically uses energy from the Battery for system tests and recharging the 12V battery when necessary.

There is no advantage to waiting until the Battery’s level is low before charging. In fact, the Battery performs best when charged regularly.

NOTE: If you allow the Battery to discharge to 0%, other components may become damaged or require replacement (for example, the 12V battery). In these cases, you are responsible for repair and/or transporting expenses. Discharge-related expenses are not covered by the warranty or under the Roadside Assistance policy.

The peak charging rate of the Battery may decrease slightly after a large number of DC Fast Charging sessions, such as those at Superchargers. To ensure maximum driving range and Battery safety, the Battery charge rate is decreased when the Battery is too cold, when the Battery’s charge is nearly full, and when the Battery conditions change with usage and age. These changes in the condition of the Battery are driven by battery physics and may increase the total Supercharging duration by a few minutes over time.

Battery Care

Never allow the Battery to fully discharge. Even when Model 3 is not being driven, its Battery discharges very slowly to power the onboard electronics. The Battery can discharge at a rate of approximately 1% per day, though the discharge rate may vary depending on environmental factors (such as cold weather), vehicle configuration, and your selected settings on the touchscreen. Situations can arise in which you must leave Model 3 unplugged for an extended period of time (for example, at an airport when traveling). In these situations, keep the 1% in mind to ensure that you leave the Battery with a sufficient charge level. For example, over a two week period (14 days), the Battery may discharge by approximately 14%.

Discharging the Battery to 0% may result in damage to vehicle components. To protect against a complete discharge, Model 3 enters a low-power consumption mode when the displayed charge level drops to approximately 0%. In this mode, the Battery stops supporting the onboard electronics and auxiliary 12V

battery. Once this low-power consumption mode is active, immediately plug in Model 3 to prevent a jumpstart and 12V battery replacement.

 

[MikeyMikeD]

Exactly what he said...

Or like the old Glade commercials... Plug it in, plug it in

 

[Nayston]

I thought I read somewhere that you don’t want to plug it in everyday because then the range of the car will not be accurate. I read that you should allow the car to get down to 20% then charge up to 80/90% and keep it in that range.

people were complaining that the car started out with a range of say 300 miles and after a full charge they are down to say 266 miles. Again, I thought it had to do with the computer not recording the range appropriately due to not getting low enough to calculate correctly and therefore you should let it drain to 20% and then back up to 80/90%.

 

[jrweiss98020]

Yes, you probably did read it somewhere, and if that somewhere was the Internet, it MUST be true!

In this case, there are all kinds of rumors and opinions out there, so just drive the car and do what the manual says! If you want to "drain it to 20%", take a road trip!

 

[BuggDDS]

Plug it in, set to 90%, go about your life

 

[sightman]

And read the manual. Lots more goodies in there. I set mine to 80% plugged in any chance I can get, mostly at home as my work has no chargers.

 

[leonar40]

Same. Set to 80% and leave it plugged in at all times when at home.

 

[akenham]

Currently I am not driving very many miles and with the cold weather I have noticed that overnight the battery can drop by at least 5%.

Tthe 5% you refer to is likely the blue coloured part of the battery that is currently unavailable due to cold (snowflake icon) given recent conditions in the UK.

It's not lost - it's just unavailable as the battery is cold.

In context, without sentry and waking the car (app use, opening doors) my car is taking days to genuinely consume 2-3%.

So my question is... would it be best to keep the car plugged with a charging cap of say 70%, i assume that if I put it on charge it will charge to 70% and then kick back in to stay at 70% ifit drops below

As others have said, plug it in.

It won't micro-charge every time it drops below the set % - the BMS is sensible and waits to get a few percent below before kicking in and charging - I have the notifications for charge start/stop on and at present in lockdown it only charges after I do my once per week grocery run.

Or leave it off charge and losing battery and just top up when needed?
The car came with a full charge and I have add 46wkh, I have done 120 miles and now have 30% battery, does this seem like high battery usage?

Which is the most cost effective way of running the car?

You can't extrapolate from short trips in cold weather - both use an unrepresentative amount of charge - there's a "departure tax" that you pay once to warm the cabin and battery.

Cost effective - I think of several variables in priority order

1. Having car ready to use when I need it with enough charge to be useful
2. Charging on cheap rate electricity overnight (5p vs 14p per kWh for me)
3. Not unnecessarily doing things that shorten battery life (shallow charge cycles preferred; >90% or <10% avoided unless needed)
4. Keeping the car plugged in so that nothing unexpected can happen (so it can manage itself).

The difference 90 to 80 to 70 % charge level on battery life is likely to be marginal and putting the battery through more charge cycles than I actually need to use just to keep the BMS estimate more accurate seems... undesirable.

FWIW at present, for my personal needs a 70% level is more than enough for any driving I might do. I doubt a lower setting will do much harm to BMS estimates as I occasionally charge to 90% when I need to go further.

When I'm not locked down I just use 80% routinely and I'm done.

 

[BlueDream2]

Adding to the list; Plug it in every chance you get, set limit to 80% unless your doing a long drive. Let the computer do the thinking. The guys who wrote the owners manual actually know what they are talking about.

 

[joebruin77]

I agree with everyone who suggests to keep the car plugged in, as the manual says.

And not that you can draw large conclusions from a sample size of one, but I have had my P3D since 12-2018. I have plugged it in nearly every time I come home and have kept the upper limit set somewhere between 80 and 90%. My car started out with a range of 310 miles. As of today, according to my Stats app, my range maximum range is 311. So no, keeping the car plugged in nearly all the time at home did not damage my battery at all.

 

[Thp3]

I thought I read somewhere that you don’t want to plug it in everyday because then the range of the car will not be accurate. I read that you should allow the car to get down to 20% then charge up to 80/90% and keep it in that range..

Nah. Battery range is “balanced” when the car is charged to 90. It *might* be useful to do that seasonally. But is a reporting issue, not a battery wear issue.

I keep mine at ~70% and when fully charged they are above 300 mpc. I forget the exact number.... Stats tells me it’s 308 M3 & 316 MY.

But, the big issue in the dang 12 volt battery. It’s used a lot as the car sits. If the car is not plugged in, it doesn’t get recharged as often as it wants. Then the 12 Volt battery wears out sooner than expected ( often at one to two years). And your Tesla is difficult to access (understatement) to replace the battery.

if the Tesla is plugged in when idle, the 12 Volt battery seems like it will last 4-5 years. Then upgrade to a Lithium 12 Volt battery. Those should last longer.

 

[AlanSubie4Life]

Is the displayed range supposed to adjust based on recent driving habits?

I think the post above answers all your questions.

Equivalent to that excellent answer: It is not a range display.

Each rated mile on your display contains a fixed, constant amount of energy, that never changes over the life of your vehicle (you’ll have fewer of them available over time though!).

 

[HaroldC]

Range Tips - Tesla

Directly from Tesla:

• Maintain a regular, every-day charging routine using a low-voltage charger. It’s best to rely on high-voltage charging (i.e. Supercharging) only when necessary.
• Whenever possible, don’t let the battery go above 90% or below 20%.

 

[MyTessi88]

I charge to 90% (on my home 240 v outlet) every day from whatever level of driving I do for the day and have zero battery degradation (two months in- knock on wood).

 

[Nayston]

Yes, you probably did read it somewhere, and if that somewhere was the Internet, it MUST be true!

Well to be fair it is a stickied post under the battery section of this very website: How I Recovered Half of my Battery's Lost Capacity | Tesla Motors Club

Have others here read that thread? Seems to be backed up by some pretty credible sources within the Tesla operation, with peer-to-peer proof that it works. Are there any thoughts on this?

 

[Thp3]

Well to be fair it is a stickied post under the battery section of this very website: How I Recovered Half of my Battery's Lost Capacity | Tesla Motors Club

Have others here read that thread? Seems to be backed up by some pretty credible sources within the Tesla operation, with peer-to-peer proof that it works. Are there any thoughts on this?

again, his battery was fine, it reported less than he wanted. After energy balancing over multiple times, his battery now reports what he likes.

It did not physically wear out.

your 12 Volt might wear out very fast if you don’t keep it plugged in routinely when idle.

Your battery will degrade abit faster if you charge it often to 90+%

So unless you need to for daily driving, charge it to less than 90%.

It’s not a problem. Owning an EV is a learning experience, learning to worry about % of charge versus Miles predicted is one of the more useful items to learn.

Learning to avoid fast starts and fast cornering if you want your tires to last is another.

other novelties; wind effects, rain effects, elevation changes, cold weather, getting to a destination faster by charging more often than needed, PlugShare, ABRT, winter/summer tires, etc.... all have influence on your battery use.

 

[JCtx]

Then when I recharged that evening, the range shot right back up to 315, not 250. Is this expected behavior? Why?

Yes, because Tesla uses ideal (EPA) mileage, which makes it basically useless indeed. That's why it's WAY better to use energy level (%) instead. I initially was using mileage too, since it's our first EV, and felt familiar. But immediately realized it was useless, and we needed to get used to the idiosyncrasies of an EV car, so switched to % right away. Another thing we did almost right away (last month) is to go on a long trip, where I learned each % of charge equals about 2.5 miles at 80/90 MPH with HVAC on at 70F, and outside temps of 40/60F. That's pretty much as bad as it'd get, and it makes very easy to calculate how much to charge for the next leg. Hope this helps.