weird question -- is the 60D slightly slower since it's not 100% charge of the battery?

[hatman4731]

DragRacing youtube channel recently did a test of battery charge level's effect on the acceleration on a P100D:

Looking at pure kW output, it looks like P100D puts out 559kw at 76% and ~576kw at 99%.

That got me to thinking -- since the 60D at 100% is approximately 86% of the 75kw battery, does this mean that its power output is slightly lower than 75kw@100%? I don't think it would be enough to make a real-world difference in 0-60 but the rated 5.2 seconds would theoretically be slower on the 60D.

Anything wrong with the logic above?

 

[apacheguy]

Yes, you are correct. Voltage drop is greater as SOC declines so less power is delivered at 86% compared to 100%.

 

[hatman4731]

do you think that would translate to a real-world difference in acceleration, like 0.1s slower for 60D?

 

[chillaban]

I don't think it'll be 0.1s. A lot of manufacturers add 50-100HP to squeeze out another 0.1 seconds....

 

[joninmelbourne]

I've just upgraded my Model S 60 to 75 and at 100% it felt a little faster.

 

[sorka]

Yes, you are correct. Voltage drop is greater as SOC declines so less power is delivered at 86% compared to 100%.

Yes, but the 60D is software limited and raises current as the SOC drops to keep the power the same. Just like the regular S85 which produces about the same 320KW all the way down to 25%.

The PD cars are a different story as they max out amps at any SOC so they produce less and less power as their voltage drops.

 

[apacheguy]

Yes, but the 60D is software limited and raises current as the SOC drops to keep the power the same. Just like the regular S85 which produces about the same 320KW all the way down to 25%.

The PD cars are a different story as they max out amps at any SOC so they produce less and less power as their voltage drops.

This is not true. I have an S85. The DU will not exceed 1000 amps at any SOC.

 

[sorka]

This is not true. I have an S85. The DU will not exceed 1000 amps at any SOC.

Then your S85 is defective. I've logged 320KW on an S85 all the way down to 30%. Also the power at the wheels using a vbox is identical at 95% and 30% as is acceleration to 60.

Even the earliest 85 battery can pull up to 1155 amps.


<entry key="17">
<dict>
<entry key="value"><str>S3_17</str></entry>
<entry key="packType"><str>S3</str></entry>
<entry key="maxCurrent"><int>1155</int></entry>
<entry key="capacity"><int>85</int></entry>
</dict>
</entry>

The S85 can produce 320K all the way down to 277 volts.

 

[apacheguy]

Then your S85 is defective. I've logged 320KW on an S85 all the way down to 30%. Also the power at the wheels using a vbox is identical at 95% and 30% as is acceleration to 60.

Even the earliest 85 battery can pull up to 1155 amps.


<entry key="17">
<dict>
<entry key="value"><str>S3_17</str></entry>
<entry key="packType"><str>S3</str></entry>
<entry key="maxCurrent"><int>1155</int></entry>
<entry key="capacity"><int>85</int></entry>
</dict>
</entry>

The S85 can produce 320K all the way down to 277 volts.

Hmm. Can I see this data? My S85 has never exceeded 1000 amps. And that includes the new -Q DU that Tesla installed last month. The pack may very well advertise a max current higher than 1000 amps but a non-perf DU will not exceed 1000 amps.

 

[sorka]

Hmm. Can I see this data? My S85 has never exceeded 1000 amps. And that includes the new -Q DU that Tesla installed last month. The pack may very well advertise a max current higher than 1000 amps but a non-perf DU will not exceed 1000 amps.

What exactly are you measuring and with with? Battery output because that's what I'm measuring.

 

[apacheguy]

What exactly are you measuring and with with? Battery output because that's what I'm measuring.

I've measured power output with the rest API. I've also directly recorded battery current and voltage over CAN.

See this Dragtimes video with an S85. Approx 40% SOC and it does not come close to 320 kw. In fact it is limited. This is consistent with my S85. I am really unsure how you ever managed more than 1000 amps in an S85.

2014 Tesla Model S 85 kWh 0-60 MPH Testing

 

[Hrhkee]

DO you have economy mode on?

 

[apacheguy]

There is no such thing. Range mode? No, I've never enabled that.