V3 Supercharging Profiles for Model 3
Based on
@Zoomit's plots above, looks like @90% (with a
fully warmed battery) you'd be limited to 35kW.
Power = m * a * v
For the situation I mentioned above, we were dealing with 1400 feet descent over 5 miles. This is about a 5% grade.
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To maintain speed (at say 45mph), you need:
Power = m * sin (alpha) * g * v = 19.7kW
Where alpha is the angle of the slope (not the grade), alpha = arctan(0.05) = 0.0499
FWIW, (sin(tan-1(grade)) is approximately equal to the grade for "typical" grades...
So with a warm battery it would be no problem to go slowly enough on such a grade.
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For actually slowing down, forgetting about the slope, you'd be limited to 35kW with a warm battery, which works out to be (at 45mph):
a = 35kW/(m*v) = 0.089g.
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This isn't a lot of slowing (certainly not enough for an abrupt stop), but 0.09g is actually a fairly noticeable stopping force. It's enough to keep you going quite slowly on fairly steep grade...per the above, it's basically enough to keep your speed at 45mph if you're going down about a 9% grade (which is quite steep!).
But again, in the OP's situation, and the situation I described, the battery is not up to temperature, so you won't get the full 35kW.
Going back to our situation I described above, we were at 69% SoC. In
@Zoomit's plot that corresponds to 95kW maximum charge rate for a warm battery. Based on us needing to use the brakes on a 5% grade with a cold battery (this requires ~20kW to maintain speed at 45mph),
empirically, it looks like the regen with a cold battery is limited to less than one quarter of the maximum possible value at that 69% SoC.
I'm not taking into account conversion efficiency losses and drivetrain losses in any of the above. In general taking those into account would mean the regen energy allowed into the battery is even more limited with a cold battery than stated above.