- First Name
- Yves
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- Jan 28, 2024
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- BMW iX / Macan Turbo
It simply is not true. You can look at the Porsche Taycan graph posted by degenatron.
The difference between preconditiong and not is ~10C. There is no point on the curve where a 10C difference in battery temperature doubles charging performance. It shows a 3.5 minute loss from 20C to 10C.
These screenshots mean nothing. They are different charging stations in different seasons on different drives. You are not showing the temperature difference or the starting SOC. This is not a comparison of preconditioning vs. not.
It is really very simple. Start one drive on one day and drive to the DC charging station using CarPlay or without setting a PCM nav destination. Note the starting and arriving temperatures. Note the charge time delivered from the same starting and ending points and the total kWh delivered.
Now do the same thing, setting a PCM destination. You will find that the battery is 5-10C warmer when arriving, but no different in temperature after ~5 minutes. You will also find that the total duration of the charging stop doesn't extend by double. You simply cannot lose that much charging time over a 10C temperature difference. It's a 10-15% maximum difference in charge rate.
No, it's not what you posted. You posted a completely uncontrolled test from two charging stops that have no relationship to each other.
The fact that one charging session is faster or slower is absolutely not down to a couple degrees of temperature difference. This really is just physics. The graph is right there from Porsche. Take any point on that graph and move up or down 10C. Is your charging speed doubled? Absolutely not.
Watch your car next time you DC fast charge. How far does the temperature increase while driving? How much higher and faster does it go while fast charging? Because you'll be cooling your car before hitting 80% charge even at -10C ambient.
I can post some actual data with actual temperatures when I get home, but you can also look at some Tesla data for similar performance: 1kW of preconditioning raised the battery 3C. Best case, mathematically, for almost all EVs is 3kW of preconditioning, or 10C. That's it.
The fantasy that you're superheating your battery into doubling charging is just not based in reality, unless you're plugging in for only 5 minutes at 10% to hit the 270kW flat curve. The 3-5 minutes savings is very much the mathematical limit. And across a normal, 20-30 minute charging stop, your SOC and the charger itself are bigger factors.
For me it is clear if the battery is not at 25C ish / pre conditioned you ride a charging curve that takes 2x time and the difference is not some minutes as I and others have clearly shown. Especially if you keep the car between 10 to 60% which the Porsche Nav is doing on a roadtrip
I did the test same day with same ambient (which is not really needed it’s the battery temp, only in hot summer that has an effect where during charging you could heat gate)
Calling it uncontrolled is just a lame trick to get your point across, that’s not how it works
Anyway you do you, I and most others here know better from real experience …
As already mentioned the difference will be less when doing a 10 to 80% for sure as both charging curves will meet at around 2/3‘s but the PCM Nav will keep your Macan in the 10 to 15 minuted charging time with a 10 to 60% … it will almost never go to 80% for this exact reason …
I will probably do a roadtrip of a 1000km in 2 weeks, colder weather and will be using the PCM Nav as I know I will easily add 30 minutes or more if I would use Apple Maps …
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