JimBob

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Pretty good conditions this morning. Winds were light under 7 mph and quartering so maybe 3-4 mph head and tail winds at most. A bit more traffic than the last tests, but probably due to warmer temperatures with people wanting to be out and about. Car was set up as before, Range mode with a target speed of 115 kph or 71.5 mph. The only issue was the cruise control was acting up. I have developed a real dislike for the PCM with all its submenus. Impossible to safely use while driving. Please bring back some buttons and dials. However I now qualify for @ron_b 's thread on efficiency. If you can, you should post your results. Some interesting things could pop out.

Next run will be at 20C/68F

Results

Metric
Mode​
Mean Air Temp Celsius​
Target Speed kph​
Distance Travelled in km​
Consumption Wh/km​
Range11.7115419208.6
Range1.2115354A/383.2E246.9A/228.1E
Range-8.7115338258.6

Imperial
Mode​
Mean Air Temp Fahrenheit​
Target Speed mph​
Distance Travelled in miles​
Consumption Wh/mile​
Range53.171.5260.4335.6
Range34.771.5220A/237.5E397.3A/368E
Range16.371.5210.1416

Charts 1 and 2 show a plot of the summary of results.

Chart 3 shows the results from this mornings run in metric.

Discussion
There may have been a small wind effect on the results. The delta on the distance between the outbound and inbound legs was 9km/5.6 miles over a total distance of 379km/235.5m. Note this does not equal the total distance, just 90% of the distance travelled. The remaining 10% is my factor of safety which I burn off close to home.

Also the plot of speed is a little jagged as cruise control wasn't used, so reflects my fat foot.

The most interesting aspect was the battery temperature. It's hard to see on the plot but it looks like the BMS was trying to keep the battery temperature between 25C and 30C. There were periods when the air temperature was rising and the battery temperature was falling. The next run should provide additional incite as the temperatures will tend to push the battery above 30C. Unfortunately or fortunately depending on ones point of view, I will never see the kind of temperatures reached in the South West US, so I will probably never see the battery stressed at high temperatures.

Hopefully I will be able to hit the sweet spot where range is at maximum. There are tests around 290 miles out there and it would be interesting to see that in detail. Also how big the sweet spot for the best range is.

Any comments or disses are welcome.




Chart 1

Chart 1.jpeg







Chart 2
Chart 2.jpeg





Chart 3
Chart 3.jpeg





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Scotty

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Very detailed information. The range was 419 K or 260 Miles. What was the exact percent of battery remaining when you achieved 260 miles ? I will be testing the range this weekend. I will be traveling 130 Miles with temperature around 95 degrees F or 35 celsius., desert conditions. I will put the car in range mode with speed set at 65mph.
 

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The next run should provide additional incite as the temperatures will tend to push the battery above 30C. Unfortunately or fortunately depending on ones point of view, I will never see the kind of temperatures reached in the South West US, so I will probably never see the battery stressed at high temperatures.
Very interesting data! Thank you.

I should see battery temp of up to 35°C in the coming months. How much it affects range I am not sure, because I cannot drive the car without the A/C to compare to my 20°C "winter" drives.
 
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JimBob

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Very detailed information. The range was 419 K or 260 Miles. What was the exact percent of battery remaining when you achieved 260 miles ? I will be testing the range this weekend. I will be traveling 130 Miles with temperature around 95 degrees F or 35 celsius., desert conditions. I will put the car in range mode with speed set at 65mph.
Observations are made and recorded at 2 minute intervals. Plotting the results at 2 minute intervals is helpful in understanding what is going on under the covers.

The outbound leg goes until 55% SOC is reached, and if there is no wind effects the inbound leg will be about the same distance. That leaves a 10% buffer to run off near home. As I am running the test on an expressway, I don't want to flirt with getting too close to 0 SOC and running the balance of the test on local streets would be at a much lower speed and not representative. When the dash is flashing red and shouting at you to charge immediately, I lose my courage.

In this case the test ended at 7% SOC. The distance travelled was 242.4 miles and the indicated range remaining was 18 miles giving a total range of 260.4 miles.

It would be nice if you could indicate your results.
SOC at start of trip
SOC at end of trip
Odometer at start of trip
Odometer at end of trip
Battery Temp at start of trip
Battery Temp at end of trip
Air Temp at start of trip
Air Temp at end of trip
Estimated effect of wind.

If the trip was at 115kph/71.5 mph to make it comparable to mine than I could add an AB line to the plot which would be a good approximation of the distance that could be travelled.
 

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To confirm this is not the performance battery plus?
 

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Not the same and not as detailed but I drove my TTS in range mode, ambient temperature of 75f on a long trip last week. I was driving efficiently but not being hyper careful. Speeds varied but mostly highway so up to 70 mph, but most at 65 mph. Air conditioning and one passenger.

On a 144 mile round trip journey with average at 40 mph I had an efficiency of 3.4 mile/KWHr (295 W/100 miles). I could have driven almost 290 miles total to empty (I was not hitting 50% by the end). I even was parked for 20 min or so with AC running.

that is very efficient. The conditions were pretty optimal (temperature and elevation wise, not much climbing), but I am still impressed.
 
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JimBob

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Another observation. Though the sample size is still small the performance of the battery is interesting.

When the air temperature is well below freezing, refer to the green line, when the car is plugged in and a departure timer set, the battery gets warmed up. In these tests, the battery was close to its hottest at the start of the trip, though air temperatures were lowest. The BMS appears to building a store of heat for the trip.

As the trip progresses, the battery temperature rises. A long time since I have had a course in EE, so any EE's should weight in but P = VI.

At the start the voltage is high so the current is low. As it is current that causes heating, the heating effect on the battery is low.

As the trip progresses, the battery voltage drops. From the plot of the SOC vs distance, the car appears to use the same amount of energy to travel a set distance at both the start and end of the trip. To maintain the same power, as voltage is dropping, current must be rising, hence the battery is heating up.

Is also why driving the car hard prior to charging will heat the battery for a better charging response.

The car will attempt to manage the battery temperature by opening and closing the vents, most efficient method or may attempt to actively cool the battery using the vehicle cooling system.

Porsche says the optimal temperature for the battery is 30C.

I am hoping that the air temps will eventually be high enough to see what is happening at those temperatures. Anyone in hot climates will see this most of the time.
 

Scotty

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Observations are made and recorded at 2 minute intervals. Plotting the results at 2 minute intervals is helpful in understanding what is going on under the covers.

The outbound leg goes until 55% SOC is reached, and if there is no wind effects the inbound leg will be about the same distance. That leaves a 10% buffer to run off near home. As I am running the test on an expressway, I don't want to flirt with getting too close to 0 SOC and running the balance of the test on local streets would be at a much lower speed and not representative. When the dash is flashing red and shouting at you to charge immediately, I lose my courage.

In this case the test ended at 7% SOC. The distance travelled was 242.4 miles and the indicated range remaining was 18 miles giving a total range of 260.4 miles.

It would be nice if you could indicate your results.
SOC at start of trip
SOC at end of trip
Odometer at start of trip
Odometer at end of trip
Battery Temp at start of trip
Battery Temp at end of trip
Air Temp at start of trip
Air Temp at end of trip
Estimated effect of wind.

If the trip was at 115kph/71.5 mph to make it comparable to mine than I could add an AB line to the plot which would be a good approximation of the distance that could be travelled.
Will do, how do i determine battery temp?
 
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JimBob

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Will do, how do i determine battery temp?
You can set the information that is displayed on the right tube of the instrument cluster using the PCM. Probably the most useful ones to show are SOC, Battery Temp, 12V and altitude.

Refer to pages 125 to 133 of the user manual
 

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