So another data point. Last week I ran out of juice. First time in 140k miles. I did 100% charge to 0% at which it shut down right when it hit 0 and there is definitely "no reserve". This was all due to tannersville supercharger being offline and torn apart so I really had no choice but to try and crawl home at 30mph. Not really my fault as I'm well aware of my range and where chargers are. (Though come to find out later someone told me that Tesla's policy is to free flatbed anyone who arrives at a supercharger and it being offline and you don't have enough range to get to your destination). Anywho, when it shut down it was showing about 60.1kWh used on the display. So yea, definitely > 20% degradation.
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I hit 0 last week on a ski trip...for over 1 mile...F-ing close! so 'buffer' may vary. 100% - 0 ended with driving 25 mph the last few miles through Grants Pass to the SC with no heat at 34F. car showed 68.3 kWhr used - data logging showed 78kWhr used.
249 at 100% w/ range mode on (~99% since it didn't ever show 100 on logs but it did finish charging) @59 K miles
249 at 100% w/ range mode on (~99% since it didn't ever show 100 on logs but it did finish charging) @59 K miles
Interesting @Zextraterrestrial
I just turned over 90K, and I'm at ~253 @ 100% (although it's been a while since I've done that).
I noticed on another thread that @yobigd20 you mention supercharging quite often.. sometimes twice a day. I wonder if that's had an effect on your pack health. Do you often charge to 100% also?
I just turned over 90K, and I'm at ~253 @ 100% (although it's been a while since I've done that).
I noticed on another thread that @yobigd20 you mention supercharging quite often.. sometimes twice a day. I wonder if that's had an effect on your pack health. Do you often charge to 100% also?
I usually do 98 or 99% when ever I leave the Humboldt Bay area but I have done 100% the last few times (Xmas/Thansgiving) and was at 251/252/250/251 the last few in 2016 (temps varied a little bit). The SC south of me is 160 miles and I can manage to use pretty much all of my range for that trip. I have raced several years of autocross and 6 or 7 autocross enduro races, not sure what that does for the battery. cooling is good but I get into to the lower power limiting by the end of the enduro races, it probably doesn't really have much degradation impact
How and why does your car display vs data logging differ in kWh used by such a large amount?
Wow, that's the lowest I've heard by far.
Do you mind expanding on your charging regimen? Supercharger vs. non-, frequency, typical max charge setting, depth of discharge, etc...
Thanks for anything you are willing to share.
In November I started comparing my hand written data to the logging through Telslafi. I am not really sure what data James uses for the kWhr usage but it seems to be close to 10% higher depending on temperatures. could be completely wrong but I am pretty sure there is more usage than what is actually shown on the dash, not sure how much in reality. The charging usage is interesting to compare SC vs home charging efficiency.
Well that's disturbing. I just saw a 120k mile P85 do 244 on a full charge a few weeks ago.
ignore what I said in the above about the kWhr on the dash vs log. the logging software just scales rated miles directly...the not being able to edit stuff here anymore really sucks...
Ulmo
Active Member
I don't know what caused it re-reading this thread in this particular post to click in my brain, but from the marketing theory:
1960('s) -- flower child
1985 -- Go-Go era for a lot of the older wealthier people during the Reagan era when they made some money
1980? 1979? Carter era? Bad, no, horrible times.
Was it purely marketing and a year connotation?
Going by that theory, they were mopping up the disco era (70, 75), and the more recently born crowd (90). 100 is just a nice round number.
How much does this make sense in terms of marketing?
JRP3
Hyperactive Member
This conclusion is not consistent with EPA testing. Based on data from the 2013 MY Model S85 calculated battery capacity is 245Ah at an average 350V or 85.75kWh, which is also consistent with the full recharge event energy of 95.507kWh, as this will correspond to the overall charging efficiency of 0.8978 (consistent with the 0.92 efficiency of the charger and charging losses in the battery).
Here is the summary of data/calculations:
EPA Data:
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llavalle
Member
Do you know for sure how the EPA measures the power fed though the charging system? Not saying you're mistaken, I'm just curious...I don't know how the EPA measures this.
Let's say you have 120/240V split phase utility connection with a 200A meter and panel. Let's call this point A. You put an accurate power measuring device in your panel, something like a 0.5% certified eGauge + some accuCTs that are revenue-grade certified. This will measure accurately the voltage at the panel + the current flowing towards your EVSE.
Now here's the thing : how long of wire do you have between your panel and the EVSE? 50ft? 100ft? 150ft? This wire will heat up and you'll get a voltage drop at the end. Wires getting inside the EVSE is Point B. Same current.. less voltage. Then this goes into the EVSE's cable, charge port, car's cabling, etc. All of these also heat up... and voltage drop again.
Then it hits the charger (Point C) and the charger knows accurately the input voltage and current. There are efficiency losses in the charger itself (around 92% for the gen2+ charger.. less than that on gen1) then there's internal resistance of the battery. Then the BMS knows checks the SOC and a bunch of other stuff and you've got a full battery (Point D)
For the sake of the example, let's assume you have a 100kWh battery. i.e. one that stores a pure 100kWh. Perfect battery, no IR, no taper. It takes exactly 5 hours to charge the battery
Now let's walk back from point D all the way up to the panel :
Point D - Battery : it had 0kWh stored.. it now has 100kWh stored.. took 5 hours.. so it was charging at a constant 20kW
Point C - Charger : assuming battery IR and charger efficiency of 92% (combined), you were pulling 20kW / 0.92 = 21.739kW
Point B - At 80amps, 25ft of AWG6 (IIRC what the HPWC is using INSIDE its cable), you lose around 1.58V.. around 126W. You're measuring 21.865kW
Point A - At 80amps, 150ft of AWG3, you lose around 4.75V.. around 380W. You're measuring 22.245kW
You check your eGauche after charging the car. and it tells you you've just put 111.225kWh in your car. And right now I'm completely ignoring the terminations of the wires! I'm pretty sure the cabling went though a disconnect so that's 2 connections + the actual disconnect. Maybe they measure like the meter would - feeding the bus bars inside the panel.. and you have the breakers + it's connection to also account for in heat loss.
You see where I'm getting at? The EPA is there to tell you how much you're going to pay at the end of the month. If they measured power right before it enters the car, it would not reflect the meter cost at your place. That why it's a bit dangerous to take these number and infer the battery capacity. I'm pretty sure that 95.507kW is a VERY accurate value of the power that was sucked up by the car during charging.. when measured in the panel.. close to the meter.
Of course I see what are you are getting at - and do not buy it. First, the testing covers car, not the source of power. So the suggestion that recharge event energy includes losses in the power supply circuit is not credible.
But most importantly, it has no bearing on the capacity of the battery which is given by EPA document as 85.75kWh, not 80.7kWh as claimed by OP.
There was also this data read from the Model S can bus, which again is not consistent with the OP claim of Tesla cheating, but is in line with the EPA data. This was posted in this thread but ignored. According to this data total battery capacity was 84.1kWh.
But most importantly, it has no bearing on the capacity of the battery which is given by EPA document as 85.75kWh, not 80.7kWh as claimed by OP.
There was also this data read from the Model S can bus, which again is not consistent with the OP claim of Tesla cheating, but is in line with the EPA data. This was posted in this thread but ignored. According to this data total battery capacity was 84.1kWh.
llavalle
Member
You realized the first thing that guy said is "Can bus data from a new 85D with only 300km on odo.". 300km = not a single cycle on the cell. AKA.. the BMS has no clue.. and probably assumes a static value.. a default value. We can't know cause we don't have access to the BMS code but it must start with some sort of value right?
I have CAN readings from my 85D at around 3700kms (around 10 cycles)and I had around 82kWh total.
A while back a now former Tesla employee provided me with some privacy sanitized raw fleet data which included, among other things, the battery type, battery capacities, and mileage of every single Model S/X that existed at the time.
Zero Model S vehicles with "85" packs have 85 kWh capacity.
Zero Model S/X vehicles with "90" packs have 90 kWh capacity.
Zero Model S vehicles with "85" packs have 85 kWh capacity.
Zero Model S/X vehicles with "90" packs have 90 kWh capacity.
llavalle
Member
Every single time the battery is drained / charged, the BMS adjusts this value according to what it can sense : current that went though its shunt, soc, etc. Using an algorithm that we don't have access to, it tries to predict the available capacity according to the current voltage of the battery.
The software that runs on the BMS cleary starts with some static values. i.e. Tesla has programmed the BMS on a brand new 85D to assume that the pack has 85kWh of full capacity including a 4kWh buffer (81kWh usable).
After a few cycles, the BMS adjusts this value (down) because the pack doesn't have the programmed capacity.. so you see a lower value.
That 84 you're seing there is on 85D with 300km on the odometer. Let's assume that car came 90% charged from the factory... guy drained it while driving 300km (less than a full charge) then did a 100% range charge. I.e. BMS has only seen a partial cycle. It doesn't know the actual voltage curve of that specific pack when it hits around 5%... so it must assume that the pack behaves according to some sort of lookup table it has.
My point is.. until you've done a couple of full cycles (100-0-100), the BMS can't know for sur how much power it can get out of the pack... and at 300km on the odometer, no way this BMS has seen a single 100-0-100.
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