MASTER THREAD: Range Loss Over Time, What Can Be Expected, How to Maintain Battery Health

[Candleflame]

For those guys plugging the car every day, have you tried charging to 100%, turning sentry/summon on demand/overheat protection/etc off, and then letting battery discharge to 30% or so over a few days, so the SOC is reported overnight at different SOCs? That supposedly 'recalibrates' the algorithm, for what I've read. Then charge back to 80% max. It'd be best to do that every 3 months or so. But let's hear from an expert like AlanSubie, and see what he says .

it only recalibrates if you are not calibrated. which doesnt apply to most users.

 

[Candleflame]

Got an ODB2 adapter finally, and plugged Scan My Tesla.
I have a July-2019 built model 3 performance stealth, delivered in Australia early September 2019.

I had reported concerns to Tesla back in December, after TeslaFi reported a sudden drop in November (from 4% degradation to 8%). Tesla analysed the log and determined a faulty 12V batteries that prevented the car from going into deep sleep mode and the BMS to do its work.
They replaced the battery, told me to charge to 100% and down to < 20% a couple of times to recalibrate the BMS.
They found that the degradation was 7.8% and was within specs.

View attachment 633514

Since the range reported has continued to drop.

Now it shows a nominal full pack of 69.7kWh (from 77.8kWh new); a 10.4% degradation after just 15 months and 14,700km (9160 miles); 66 charge cycle

What worries the most, is that it steadily goes down after each recharge.

I did to the 90 - 20% over January as discussed in that other thread; with no improvement.

What do you guys think?

Nothing to worry about?

*sugar* pack. There is some sort of problem with the initial Model 3 deliveries to Australia (which includes everyone with an australian stealth 3). A lot of people think it had something to do with the 12V battery failure which may have disabled the BMS for a month or so. I'm not so sure about that...

I'm also down to 45x km (like 8-9% degradation) with 30k km on the clock on my stealth.

Unfortunately 30% degradation is a long way away and its one of these annoying things where it unfortunately does not degrade fast enough to get an early new battery pack.

I don't think without a class action law suit there is any chance unfortunately. They advertise a 499km pack but deliver this only for the first 5-10k km following by a rapid drop way beyond what most people see.

This is also the reason things like calibrations, repeated discharges etc do not work to increase the range for us - the issue is somewhere else and something has damaged the pack causing early wear.

 

[jyavenard]

*sugar* pack. A lot of people think it had something to do with the 12V battery failure which may have disabled the BMS for a month or so. I'm not so sure about that...

That was the explanation given by Tesla and was the first time I had heard about it.
Apparently prior mid-October, the software was draining the 12V battery too much, causing premature wear.
My original delivery had been delayed by 10 days already due to a dead 12V batteries, and when the mobile technician came to change my 12V battery, the old one had a build date of October 2019 ; which leads me to believe that in all this car has seen 4 12V batteries since it was built.

I'm also down to 45x km (like 8-9% degradation) with 30k km on the clock on my stealth.

oh, you calculate the battery degradation from the "Full pack when new" figure ; mine shows 451km now. Originally it was 499km, which is "only" 9.6% degradation.

 

[Candleflame]

That was the explanation given by Tesla and was the first time I had heard about it.
Apparently prior mid-October, the software was draining the 12V battery too much, causing premature wear.
My original delivery had been delayed by 10 days already due to a dead 12V batteries, and when the mobile technician came to change my 12V battery, the old one had a build date of October 2019 ; which leads me to believe that in all this car has seen 4 12V batteries since it was built.

That would be odd because it's only our Australian Teslas which were effected by this 12v failure. I have a USA battery in mine... I think builddate was August or september. Not that that means much apparently Tesla shipped usa batteries over to us so the date on the battery doesnt tell you much. I certainly have not had any issues with my 12V battery. From looking at the sleep/wake cycles of the care when it doesnt get used it has probably lost 20-30% of its capacity over the 16 months which is ok.

The thing is that if it affects calibration that is ok (i.e. if the car gets kept awake all the time), but that is unfortunately not the case. no amount of re-calibration can undo the battery degradation which is very real.

edit:
yeah so extrapolated from your kwh max thats like 70.5kwh for me which is what I see anyway by extrapolating it from my range or from the cars computed remaining range...

 

[jyavenard]

gradation which is very real.
how many km do you see at 100%?

451

 

[Candleflame]

it would be interesting to rip a few cells out of the initial australian model 3s and see how much charge they hold... whether its all just a huge BMS issue or real degradation.
I have not heard of anyone requesting a CAC reset for those cars...

Maybe you could request one given that Tesla acknowledges that you might have a BMS issue?

 

[Candleflame]

451

https://www.reddit.com/r/teslamotors/comments/cdzseb/battery_degradation_fix/

 

[ucmndd]

you can improve your range by drafting behind other vehicles. Especially if you can get behind a box truck, van, semi. Then you can go 80 and the penalty is similar to driving 60.

Or, charge along the way for 10 minutes and drive as fast as you want without needing to do something utterly stupid like “drafting” a semi going 80mph.

 

[Watts_Up]

My buddy got a 2018 long range AWD 22k miles from Tesla last week.
he finally charged to 100% and only got 281 and we left to Vegas from SoCal
and only went 200 miles before we were under 18 miles left.
Aero wheels and highway speed was about 78-80.
- Does 78mph really kill the range that fast?
Vegas is 241 from my house so we thought we would make it all the way there.

You should review the consumption graph of your trip. (Like this graph from this thread)

When looking at the elevation map, there are some major passes of two thousand feet or so.

So I imagine that when starting from Los Angeles, a major part of the energy was used to reach Victorville

You should use ABRP to have a better idea of the trip consumption and range.

I just made a quick search using your input (2018 M3 LR AWD 18") starting from San Bernardino.

With a speed a 65 miles per hour from San Bernardino to Las Vegas, and a speed of 68 miles per hour on the way back
the ABRP tool using a 278 Watt per miles at 65 miles per hour let you make the ride without using a supercharger.

This tool is quite reliable but I don't think it includes a possible loss of 2 to 4 % for the battery capacity for this 2018 car,
also you have to consider wind and temperature and number of passengers and luggage and so on.

 

[Watts_Up]

A more realistic situation would be to use a speed limit of 78 miles per hour as you mentioned,
and I found the following trips information:

You can noticed that the total trip duration are very similar between
- lowering the speed to avoid superchargers, and
- driving faster but making quick stops at a supercharger.

 

[DonTom]

does 78mph really kill the range that fast? Vegas is 241 from my house so we thought we would make it all the way there.

I believe the mile spec is for 65 MPH and seems accurate to me at that speed. The best range is at 38 MPH, IIRC, and at that speed, expect better than 400 miles of range,

At 78 MPH, I would expect poor range.

If you can drive a steady 65 MPH, you should be able to do the 241 miles, if not better. Set the cruise control when you can.

-Don- Reno, NV

 

[jyavenard]

https://www.reddit.com/r/teslamotors/comments/cdzseb/battery_degradation_fix/

But that may change the estimated range, not the reporting of the nominal capacity right?

 

[Candleflame]

But that may change the estimated range, not the reporting of the nominal capacity right?

nominal capacity is the BMS estimated range/capacity.

nominal capacity is just your rated range multiplied by a constent (like 0.147wh for the model 3 performance/awd) or even easier to just multiple the true estimated range x average consumption in the trip meter when charged to 100%, or close to 100%.

 

[KenC]

Using ABRP, you need 112%, with a battery 10% degraded, to make it at 80mph. A stop only takes about 12 to 15 min.

 

[TMThree]

Or, charge along the way for 10 minutes and drive as fast as you want without needing to do something utterly stupid like “drafting” a semi going 80mph.

No one said tailgate. You draft behind other vehicles all the time.

There's a huge difference between being head of the line or being behind other vehicles. Try it sometime instead of mouthing off.

 

[ucmndd]

No one said tailgate. You draft behind other vehicles all the time.

There's a huge difference between being head of the line or being behind other vehicles. Try it sometime instead of mouthing off.

Sorry boss. Your post and assumptions (i.e. " you can go 80 and the penalty is similar to driving 60") are just plain wrong.

Digital Debunking: Could Drafting Really Improve Fuel Efficiency on the Highway? - The Altair Blog

...However, to get any noticeable reduction in energy expenditure, you would have to follow at an unsafe distance for a human driver’s reaction time. To gain any benefits in fuel economy, you would be putting yourself in danger of a collision if the truck came to a sudden stop.

 

[MarcG]

“if the truck came to a sudden stop”

Curious minds inquire: Unless a loaded semi hits a wall, how does it come to a “sudden stop”?

 

[MountainRatMat]

A more realistic situation would be to use a speed limit of 78 miles per hour as you mentioned,
and I found the following trips information:

You can noticed that the total trip duration are very similar between
- lowering the speed to avoid superchargers, and
- driving faster but making quick stops at a supercharger.

View attachment 633538

View attachment 633539

What terrible advice by ABRP on the route out to Vegas, you want to arrive at a Supercharger with a much lower state of charge to improve charge rate. Go to Baker, top up for 15 min then on to Vegas.

The route back home is much better, it is much faster to arrive at a Supercharger with a lower state of charge than high state of charge because the battery will charge faster that way.

 

[elptxjc]

If you can drive a steady 65 MPH, you should be able to do the 241 miles

I don't know if you'd do that yourself, but I'm using your example to say that I don't get that mentality. I get that some folks might want to minimize charging time, but the idea to drive 3-1/2 hours without even a bathroom stop, having to charge to 100%, and arriving with basically no range left (if nothing goes wrong, like a head wind, etc), is just utterly crazy to me. And it was proven above that you can drive as quick as you want, make 1 bathroom/break stop (let's say 15 min), and actually make less time, while driving more relaxed, alert, comfortable, and arriving with a decent safety margin.

I've never heard of people driving ICE cars gambling with the amount of fuel so they can get with as low reserve as possible; it makes no sense on an ICE or EV car. We knew right off the bat we'd have to spend more time charging than fueling when we bought the Tesla, but we'll never hyper-mile, or do crazy crap like that just to maximize the distance from supercharger to supercharger, when you don't even save time overall. But to each his own, I guess . We'll keep doing 150-mile legs when possible; it's nice to have a break by then, and the car is charged when done.

 

[MountainRatMat]

I don't know if you'd do that yourself, but I'm using your example to say that I don't get that mentality. I get that some folks might want to minimize charging time, but the idea to drive 3-1/2 hours without even a bathroom stop, having to charge to 100%, and arriving with basically no range left (if nothing goes wrong, like a head wind, etc), is just utterly crazy to me. And it was proven above that you can drive as quick as you want, make 1 bathroom/break stop (let's say 15 min), and actually make less time, while driving more relaxed, alert, comfortable, and arriving with a decent safety margin.

I've never heard of people driving ICE cars gambling with the amount of fuel so they can get with as low reserve as possible; it makes no sense on an ICE or EV car. We knew right off the bat we'd have to spend more time charging than fueling when we bought the Tesla, but we'll never hyper-mile, or do crazy crap like that just to maximize the distance from supercharger to supercharger, when you don't even save time overall. But to each his own, I guess . We'll keep doing 150-mile legs when possible; it's nice to have a break by then, and the car is charged when done.

I disagree with your 2nd paragraph. I try and keep my battery state as low as possible while still leaving a safety margin that I feel comfortable with. I usually aim for 15% SOC at a supercharger which always ends up lower and I don't feel comfortable going below 5%. Unlike an ICE car the "fuel" tank fills faster at lower SOC where as an ICE car doesn't fill gas any faster with an empty tank.