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Model S Battery Voltage?

There is an old thread asking this question, but it went off topic and died about a year ago. Question never answered.

What is the voltage of a Model S battery when charged 100%, that is, a full range charge?

From other threads, it appears that the maximum allowed cell voltage is 4.1. Using 4.1 volts, 16 modules, and a multiplier of 6, I come up with 393.6 volts for a fully charged pack. Seems reasonable to me, as the Model S Emergency Response Guide says the battery is 400 volts, which is what it would be if cells were charged to 4.2 volts using the same formula. (Actually 403.2 volts)

Interestingly, that is exactly what a LEAF battery voltage is at full charge - 96 cell pairs at 4.1 volts = 393.6 volts, and the LEAF Emergency Guide says the battery is 403.2 volts.

There is an old Tesla document that says the Roadster battery nominal voltage is 375, which is what you get using my formula at 3.9 volts per cell.

Yes, lots of guessing here, anyone know?
 

yobigd20

Well-Known Member
Oct 28, 2012
5,947
564
Skaneateles, NY
There is an old thread asking this question, but it went off topic and died about a year ago. Question never answered.

What is the voltage of a Model S battery when charged 100%, that is, a full range charge?

From other threads, it appears that the maximum allowed cell voltage is 4.1. Using 4.1 volts, 16 modules, and a multiplier of 6, I come up with 393.6 volts for a fully charged pack. Seems reasonable to me, as the Model S Emergency Response Guide says the battery is 400 volts, which is what it would be if cells were charged to 4.2 volts using the same formula. (Actually 403.2 volts)

Interestingly, that is exactly what a LEAF battery voltage is at full charge - 96 cell pairs at 4.1 volts = 393.6 volts, and the LEAF Emergency Guide says the battery is 403.2 volts.

There is an old Tesla document that says the Roadster battery nominal voltage is 375, which is what you get using my formula at 3.9 volts per cell.

Yes, lots of guessing here, anyone know?

I was going to say its around 400-440 volts but looks like u know more than me regarding a more precise amount.
 

stopcrazypp

Well-Known Member
Dec 8, 2007
12,636
8,532
This post talks about it:
While Model S supercharged at Refuel, I noticed a 60 kWh model tapering current to 32A at 352V while the 85 kWh model was finishing at 37A and 402V. These were values indicated on the dash.
402V / 96 cells is 4.19V and that makes sense for top of charge.
352 V at the same cell voltage would indicate that the 60 kWh unit only has 84 bricks of parallel cells in series.

The architecture appears to be:
85kWh: 16*6*4.19 = 402V
60kWh: 14*6*4.19 = 352V

Keep in mind this is the charger's tapering voltage and the actual voltage when you take it off the charger is probably going to be slightly lower.
 
This post talks about it:

The architecture appears to be:
85kWh: 16*6*4.19 = 402V
60kWh: 14*6*4.19 = 352V

Keep in mind this is the charger's tapering voltage and the actual voltage when you take it off the charger is probably going to be slightly lower.
Thank you. And, yes, there will be a drop when removed from the charger.

I copied these voltages from a Tesla generated comment concerning the Roadster battery:

4.10 volts = full standard mode (187-195 ideal miles)
4.15 volts = full range mode
4.20 volts = maximum of the cells that we never touch

So, using 4.15 volts per cell, we get 6 x 16 x 4.15 = 398.4 - pretty darn close to 402.
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,089
179
Colorado
This post talks about it:


The architecture appears to be:
85kWh: 16*6*4.19 = 402V
60kWh: 14*6*4.19 = 352V

Keep in mind this is the charger's tapering voltage and the actual voltage when you take it off the charger is probably going to be slightly lower.

Pretty close! Here is a snapshot of the App on my iPhone as I almost finished a Range charge on the Silverthorne Supercharger so I could make it to Pagosa Springs non-stop. A full Range charge for me these days is 263 miles, so this was only 2 miles short of a full charge, and the battery was at 403 Volts.

BTW, the charging rate was only 6.5 mph at this point, not 44 mph as the car was reporting. The App and the car report charging rate that is the average for the charging session when on a Supercharger, and the Supercharger had reset recently, so this is the average of an almost full session.

End of Charge.PNG
 
So, I was trying to summ up everything , and got some issues. When I try to calculate the amps.
If go by the formula, I got 0.15 amps, if go by the cell amount 150A. The reason I am doing that is I wanna compile my own battery to use in my tesla based conversion, I want 2 tesla small engines (~250kw each), in my project car.
 
1) 99s / 416v max – Roadster 2008-2011

2) 96s / 400v max - Model 3 Long Range 80.5kWh max capacity 96s * 46P, 4426 quantity of 2170s @ approximately 4900mah per cell, 4 modules

3) 96s / 400v max – Tesla 85-90-100kWh cars, NIssan LEAF, BMW i3, Kia Soul EV, Chevy Volt & Bolt EV,

4) 92s / 386v max – 2012-2014 RAV4 EV

5) 88s / 379v max – Smart ED, VW eGolf

6) 84s / 354v max – Tesla 40-60-70-75kWh cars, Mercedes B-Class ED / B250e

****************

99s * 69p = 6831 cells * (2600mah * 3.65v) = 64.8kWh (Roadster)


96s * 86p = 8256 cells * (3400mah * 3.65v) = 102.5kWh ("100" car)

96s * 74p = 7104 cells * (3400mah * 3.65v) = 88.1kWh ("90" car)

96s * 74p = 7104 cells * (3100mah * 3.65v) = 80.4kWh ("85" car)

96s * 46p = 4426 cells * (4900 * 3.65v) = 80.5kWh (Model 3 LR)

92s * 48p = 4416 cells * (2600mah * 3.65v) = 41.9kWh (2012-2014 RAV4 EV)


88s * 22p = 1936 cells * (2600mah * 3.65v) = 18.3kWh (Smart ED)

84s * 74p = 6216 cells * (3400mah * 3.65v) = 77.1kWh ("75" car and software limited "70" and "60")


84s * 74p = 6216 cells * (3100mah * 3.65v) = 71.3kWh ("70" car)

84s * 64p = 5376 cells * (3100mah * 3.65v) = 60.8kWh ("60" car and software limited "40")

84s * 44p = 3696 cells * (2600mah * 3.65v) = 35.1kWh (2014 - newer Mercedes B-Class ED / B250e)


The maximum charge rate for:


Small battery 60-70-75 kWh cars (excludes early 60) - 354 volts max

365 -370 amps at about 320 volts (17% SOC) = 116kW


Big battery cars 85-90-100 kWh (exclude 90kW limited "A" packs) - 403 volts max

330 - 335 amps at about 350 - 365 volts (Low% SOC) = 118kW


 
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