Interesting SuperCharging data & charts on E-pack battery (P85D)

Hi guys,

I've had my P85D for almost two months now, and over 4,000 miles later I'm collecting more and more data to understand how the beast works :biggrin:

Today, I present you SuperCharging data that I collected over the weekend. A few points to note before diving into it:

1. This is data from the Roseville, CA supercharger where there are 7 stalls
2. I used the 4A stall (there is no 4B, unlike the other three A/B pairs) which probably means it has its own unshared cabinet
3. Ambient temperature was 15ºC, or 59ºF
4. I started charging with 46 rated miles left (about 18% SoC)
5. The goal was to reach 100% SoC since I was driving far with no charging options
6. Data was collected through VisibleTesla

With that out of the way, here is the Voltage/Current/Range/SoC/Rate of Charge graph!




At the beginning of the charge, I got about 115.4 kW of power (363V x 318A):




A little while later I hit the peak charging "speed" of 361 miles per hour of charge! Although power was a lower 112.5 kW:




So here are some interesting findings:

A. Battery current peaked very early (around 320A) then tapered off in an inverse log fashion
B. Voltage started around 370V and kept going up steadily to just over 400 V, where it stayed constant from 90-100% SoC
C. Rate of charge peaked early, after about 7 minutes, then tapered off steadily in a linear fashion
D. State of Charge (and hence Range) increased rapidly until about 50%, slowed a little until 80%, then slowed a lot after 90%
E. SOC and range stayed at the same level for the last ~10 minutes of charge
F. The P85D is rated at 253 miles of range, but I was able to get 254
G. The charging "speed" was lower (354 mph) at 115.4 kW than it was (361 mph) at 112.5 kW, so I'm not sure how that's calculated
H. Tesla advertises a charging speed of 170 miles per half-hour of charge, which means 340 mph - not sure if that's peak or average

Enjoy!
-Marc

TexasEV said:

The 170 miles in "as little as" 30 minutes is when starting with a battery that is almost empty. You can't extrapolate that to the next half hour to get an average miles/hr, even if you are starting with an empty battery, and the 170 is best case scenario. Most sessions start with more than 10% state of charge and would get less than 170 miles added in 30 minutes.

Click to expand...

I looked back at all my supercharging data since I got my P85D, and the three events where I charged around 170 Rated Miles (RM) are:


So it doesn't look like it's achievable to get 170 Rated Miles in 30 minutes, at least not in the P85D...

apacheguy said:

That's great stuff. Now can you plot charger power vs SOC?

Click to expand...

VT unfortunately doesn't sample power as often as SoC (or Voltage, Battery Current, Range, etc.) but here you go anyway:



If I could manipulate the source of the data, I would just multiply Voltage by Battery Current and plot Power accordingly.

apacheguy said:

@jpasqua - Any interest in addressing this issue in a subsequent release?

@MarcG - Here's what a taper curve looks like for us "classics" in case you're interested:

Older Teslas limited to 90kW Supercharging - Page 160

Click to expand...

Thanks! I've read something similar before.

@Joe, I'm assuming that the grey Power curve you're reporting in VT is what Tesla sends, not one you're computing within VT.
So I think the suggestion would be to have another power curve labeled "Charge Power" that is your own computation of Voltage vs Current (kind of like how you have Current vs. Battery Current).