Robaire
Member
Thanks for the helpful info. We tend to have cars a long time. We had a Honda CRV in our family for 16 years. So, I'd hope our M3LR will last this long.
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Battery Degradation question
- Thread starter robl45
- Start date
At least half of my 100% SOC charges has been for "my nerd science".
Would have been enough with 80-90% for these. But the other 50% was due to the need.
johnny_cakes
Member
I did a 100% charge and also down to 5% SoC (0% usable SoC according to TeslaMate) for my nerd science as wellAt least half of my 100% SOC charges has been for "my nerd science".
Would have been enough with 80-90% for these. But the other 50% was due to the need.
My ‘21 M3P with 26k miles just took a large range hit, 100% = 275 miles of range. I feel like it was always closer to 300 then just dropped like a rock. Ideas?
Even worse, my 201 mile drive home is projected to use 79% of my battery, equating to a 100% range of just 253 miles…
Make that 86% of battery to go 201 miles, implying 100% = just 234 miles
WTH?
WTH?
I asked Tesla to run a battery test and they said my degradation was normal for my car age. They said the Tessie app is overstating things. Regardless, that sounds about right what you got, probably about what I get too.
When you say projected, you mean on the energy screen? That doesn't help calculate battery capacity. It means you're driving is less efficient than EPA asumptions which includes at least half city driving which is more efficient, and the EPA highway driving is slower than most people as well.
What's your Wh/mi average? It must be high.
If I drive moderately, I can come close to EPA. I also have the 3LR which has more efficient tires & wheels (this matters a huge amount). I've done full 280+ mile round trips on mostly SoCal freeway speeds, 65-75, and arrived home at 15%, starting from 100%. I can get 235-240 Wh/mi if I'm gentle.
To get a better sense of battery range, hit the battery bar and switch between miles and percent on the top part of main display. Those are "EPA miles". Take the miles and divide by the percent (as a fraction less than one). That's a rough extrapolation of full-range energy the BMS thinks it has now. I have very little degradation over almost a year, thanks to charging up to 50% almost every day other than road trip days.
You maybe can select 20” überturbine to check with the ”standard” rsted comsumption?
I think its about 5% more range with 18”/19” but im not sure, my car has a bug with all wheels but 20” Überturbine.
I nu would guess a batt capacity about 76kWh, out of 82.
I have done a check of ABRP* vs correct values lately. Only one car, but in that case ABRP sucked. I wouldnt thrust it that much.
Could be right of course in this case.
I have about 78.5 kWh capacity left, 2021 M3P (dec ’20), 62 K km / 38.5 K mi. About 495 km on a full charge (w/20” Überturbine selected).
About 45 supercharging sessions and have charged to 100%
*) Model S P85DL. APRB app said 4.1% degradation and 74.3 kWh capacity. This after 170K km and several years. After questioning ABRP that owner did get Tessie, which said 6.7% degradation and 72.3 kWh capacity.
After requesting the full charge range, the owner charged full, which gave 362 km@100%. New range was 407km, and the charging constant 200Wh per km so 72.4 kWh capacity, including the buffer. The new capacity of that battery was 81.5kWh, total capacity (incl buffer).
"Real" values: 72.4kWh, 11% degradation
ABRP: 74.3 kWh, 4.1% degradation.
Tessie: 72.3 kWh, 6.7% degradation.
Tessie mixes up the full capacity with the net capacity, but at least they seem to calculate the actual capacity correct, but they need to learn that they do not get the net capacity, its the total the calculate. ABRP...
Its a quite big difference between 4.1 / 6.7 and 11. At least when I learned math.
For apps not coming close to what the app owners pay for:
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ABRP seems to be getting it's data from the Tesla API, so ... I presume it's tesla's data that's wonky then. ABRP is claiming degradation of 0.4% or somesuch (less than 1%) which ... Huh? That would only be true if it's a 75 kWh usable battery? I guess 75 kWh is a round number, so plausible, but ... ...
One thing to keep in mind that once you have degradation, you tend to stress the battery more as with each trip, you have to use more of the remaining available capacity, which also results in a deeper discharge cycle as well as a tendency to charge more to compensate. It basically becomes a feedback loop that makes your situation worse.
You end up having to charge to a higher level initially which is bad. You end up with an overall deeper discharge cycle which is bad. Or you end up going to a very state of charge like close to 0%.
Even if you don't care about battery degradation, if we all can get batteries to last longer, it means less, waste and overall better for the environment and keeps costs down for everyone.
@AAKEE - I just started reading through this. It looks pretty interesting so far. I didn't know if you saw it. It is from the Royal Society of Chemistry (UK). Others might find it interesting even if you just read the first few pages.
You end up having to charge to a higher level initially which is bad. You end up with an overall deeper discharge cycle which is bad. Or you end up going to a very state of charge like close to 0%.
Even if you don't care about battery degradation, if we all can get batteries to last longer, it means less, waste and overall better for the environment and keeps costs down for everyone.
@AAKEE - I just started reading through this. It looks pretty interesting so far. I didn't know if you saw it. It is from the Royal Society of Chemistry (UK). Others might find it interesting even if you just read the first few pages.
Candleflame
Active Member
In the model S case I checked, there was two issues:
-calculating the actual capacity wrong (too high).
-using the wrong initial capacity. In this case they used the new capacity value but without the buffer. ABRP probably think that the value they calculate for actual capacity is without the buffer/net capacity when it instead IS the total capacity. (This is the same mistake as Tessie does).
It wont be right until they understand what they are doing.
For the actual capacity size they probably do it as Tessie does, or about the same way (using the charged energy number from teslas API). “The problem” is that that value is 4.7% too high (1/0.955).
This comes from the way Tesla hides the buffer. If you charge from 0-100% Tesla will report the charged energy as the whole capacity including the buffer. (Even that the 4.5% buffer size was not “empty” and was not charged.
Candleflame
Active Member
yeah teslafi has the same issue which is why calculated consumption and chargerange is never correct.
The most accurate way is to read out the kwh with SMT to be honest.
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