Muzzman1
Active Member
I've found a pretty real world estimate would be 75.9*Percentage will give you a pretty precise quantification of how many Kwh are left in the "usable" part of the 85Kwh battery.
ie : 75.9*.9= 68.31Kwh
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I've found a pretty real world estimate would be 75.9*Percentage will give you a pretty precise quantification of how many Kwh are left in the "usable" part of the 85Kwh battery.
ie : 75.9*.9= 68.31Kwh
Mario Kadastik
Active Member
Hm, I thought I had posted it to this thread, but maybe it was another similar one. Here's one of my most extreme examples of driving 
This was on 5.8.4 firmware so there seems to be some reserve left still and it looks like the 81.1kWh from 100% to bricking protection is fairly accurate. However these days with 5.9 I've not been able to get anywhere close to that amount of kWh before I hit 0% so it's hard to say. Haven't been able to push it either and haven't had the opportunity in a safe environment to test.
The latest close to 0% encounter was when I drove over 420km and in the middle recharged for 1h at 3x13A adding 40km. That should be 7.6-8kWh. I then reached my destination and the car showed Charge Now just as I pulled in. Here's the pic:
Now if you do the math and remove the 7.6kWh from it, then you end up with 74.1kWh for 100% -> 0% and this is on 5.9 where as I understood most of the hidden reserve was brought back to above 0. Now it could be that I've lost that much range, but it's unlikely as my car charged a week ago to 505km range and at the same time my used average 190Wh/km is below the rated range of 200Wh/km so I'm a bit puzzled recently.
This was on 5.8.4 firmware so there seems to be some reserve left still and it looks like the 81.1kWh from 100% to bricking protection is fairly accurate. However these days with 5.9 I've not been able to get anywhere close to that amount of kWh before I hit 0% so it's hard to say. Haven't been able to push it either and haven't had the opportunity in a safe environment to test.
The latest close to 0% encounter was when I drove over 420km and in the middle recharged for 1h at 3x13A adding 40km. That should be 7.6-8kWh. I then reached my destination and the car showed Charge Now just as I pulled in. Here's the pic:
Now if you do the math and remove the 7.6kWh from it, then you end up with 74.1kWh for 100% -> 0% and this is on 5.9 where as I understood most of the hidden reserve was brought back to above 0. Now it could be that I've lost that much range, but it's unlikely as my car charged a week ago to 505km range and at the same time my used average 190Wh/km is below the rated range of 200Wh/km so I'm a bit puzzled recently.
I'm not an expert on the model S, and I don't have exactly what you asked for. The EPA 350Wh/mile number is from the wall, though. All EVs have substantial charging losses which are included in that number - on the Volt it is usually around 20% or so. I don't have a number handy for the model S, but I suspect it is in the same neighborhood. Since you're using power from the battery in your math, you should be using efficiency from the battery too - which should put you a lot closer to 200 miles.
(This loss is a mix of electricity lost to heat in changing AC to DC and raising the voltage plus both sides of the electrical-chemical-electrical round trip in the battery. On an advanced car like the Volt or Model S, it also includes electricity to run the battery thermal management system during the charge.)
Walter
Here is a screen shot I found. It shows a hidden screen that only Tesla service can access. The interesting part is the state of charge showing 82.2% and then remaining 'ideal' capacity of 65.5 kWh. If 82.2% = 65.5 kWh, then 100% = 79.68 kWh of ideal range. I think that this will once and for all show that the nice illustration about the battery capacity that is posted over and over is inaccurate. "Ideal miles" is based on 265 Wh/miles which means very gentle driving. But either way, based on Tesla's own in car data the total usable capacity is 79.68 kWh.
It's seen speculated[1] that even at 100% the batteries are charged to ~4.15V (rather than 4.20) in order to maximize longevity. I wonder if all numbers in those screens reference 4.15 as the max charge.
I'll also note that the car seems to be able to measure current flow on the 12v battery and there's only a ~10W draw on the car at the moment while in park, but obviously on.
[1] In part due to knowledge of the Roadster systems
To me the word 'remaining' means how much is left in the battery. I don't think Tesla ever charges the battery to 4.2 Volt (or whatever the real 'full' status would be on their cells. That's just asking to kill the cells. But at the same time, remaining doesn't say if that's how much until the battery shuts down to protect itself or if that is the total amount until absolute zero.
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toto_48313
CAN P #5
On a P85D version 6.1 (2.2.102)
From 100% to 3 miles left on rated range, I used 74.8 kWh .. only 224 miles done at 45 mph avg...(was 32 F outside, and wet road.. so not ideal conditions)
From 100% to 3 miles left on rated range, I used 74.8 kWh .. only 224 miles done at 45 mph avg...(was 32 F outside, and wet road.. so not ideal conditions)
i think the 85kWh number is a nominal capacity rating that would require charging at 4.2 volts to reach. This is based upon how Panasonic refers to the energy rating of their cells found in various papers and presentations. Not sure that Tesla's "100% SOC" means using the 4.2V for charging or not--haven't reversed it yet, but i suspect that David's 79.7 kWh equals Tesla's 100%.
For example a 3.3 Ah cell would have nominal energy (at the nominal 3.6V) of 11.96 Wh; 7104 cells x 11.96 = nominal 85 kWh pack rating.
However charging at 4.2V degrades the capacity quicker (i.e. in fewer cycles) than at 4.1V, and likely why Tesla leaves margins at both the top and bottom of the "nominal" cell voltage range:
For example a 3.3 Ah cell would have nominal energy (at the nominal 3.6V) of 11.96 Wh; 7104 cells x 11.96 = nominal 85 kWh pack rating.
However charging at 4.2V degrades the capacity quicker (i.e. in fewer cycles) than at 4.1V, and likely why Tesla leaves margins at both the top and bottom of the "nominal" cell voltage range:
Cottonwood
Roadster#433, Model S#S37
For the classic (non D) model S, 300 Wh/mi applies for charging from a Supercharger, but I have found that 290 Wh/mi works best for discharge, and with AC charger inefficiency it takes 333 Wh/mi from the wall for rated miles.
Bighorn
Top Supercharger
300Wh/rated mile to charge, and I've been seeing 275Wh/rated mile realized on 6.0 in a P85+.
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