Hi Candleflame, I am not certain about the 20%, but when we sleep in the car we much prefer not to use camp mode. The main reason being that the screen remains on (amongst other things). We find the light emitted from the screen quite annoying in our otherwise perfectly dark car (we use insulating screens for all windows). Furthermore, the active systems will consume power by being on all night for no reason. Here is what we do. After installing the window blinds, we undress in the front seat, then climb to the back to get into bed. From there I tap the HVAC on the main screen (not a flattering position to find myself in), set the temperature @ 18ºC, fan at 1, airflow down and choose the option 'remain on'. Then go to 'security' on the main screen and tap 'shut down car' the car will answer with 'are you sure?' Say yes, and all systems will shut down, but the HVAC remains on. You can still use the lights in the roof above the seats if need be, and the phoneapp will also function as normal. And so we sleep. In the morning I once again maneuver myself in the non flattering position and wake the car up with some slight pressure on the driver's seat. Which switches the music on and cranks the temperature up to the set number of the preset profile. We find this very easy, by far the most comfortable and the most economic way to spend a night in our Hotel Tesla (for which I have made a bespoke mattress, screens for all windows, a bespoke fridge, changed the USB system to be able to charge phones overnight, upgraded the interior lighting system to have dimmed light at night to allow a midnight piddle inside the car without waking up my partner and created a cocktail/breakfast table that fits between the front seats and allows us to have a cold drink in the evening and watch Netflix, while brewing ourselves a cup of hot tea and coffee in the morning and enjoy a croissant. (Very handy in times of Corona lockdown when coffee bars are closed.) And there you go: 5 star hotel. The only thing missing is a shower... And possibly a microwave oven.
Lets see how you sleep in the car when its 35C and 90% humidity. Or that you have to prolong your travel by 90min because you let your car sit overnight at 5% without it charging. Which is just dumb. your post makes NO sense at all. What you state does not work when the car is plugged in and charging. And I would very much refrain from using the old parking brake trick when the car only has 5% state of charge and you need to continue your trip the next morning. What you write is literally just.... nonsense. When I travel and start in the afternoon I usually to 500-600 km, then arrive at my AC charger at <5% , plug in and go to sleep and then continue for either another 600km or 1000km the next day with a full battery. The AC charge allows me to run the AC or heating at night and also means i can start with a full battery. a 90% charge on a DC charger would take 90min. I am sure in Belgium driving 200km from one end to another is a big day and plugging in at one of the many superchargers you have + DC fast chargers is convenient but outside of europe ppl drive further and longer and without a good charging network. So they have to rely on AC charging overnight to make things a bit quicker.
I have spent many a night hooked up to a preferably) slow charger and doing exactly as I described above. Being hooked up to a charger or not does not make any difference. So what I state DOES work when the car is plugged in and charging. If what you write is correct, then it literary means a (shut down) car cannot be charged and have HVAC on simutaniously at minus 20% SOC unless someone is sitting in the car (or have a weight on the seat) . This is very untrue. I once got to a charger having 4 km left on the battery. Hooked it to the charger had the heating on straight away (it was minus 6 outside). Shut the car down and went to sleep. Woke up fully charged and nice and warm. No weight in the seat whatsoever. (and with a slow charger it allows you to charge all night long, a supercharger will make you move your after an hour, which is a bit of a drag) Nonsense or not, this works on my 2017 car. Maybe your car is different. (and I have crossed the larger part of Europe and UK in my MS, sometimes driving more than 2000km in one go.) If and when I have enough power left in the car, I loose about 50 km overnight in minus 0 temperatures, in hot weather (plus 30ºC) I loose 30 km tops. So I do not see the problem you seem to get upset about. I am only trying to point out that you do not need to put any weight in the seat. Not if you're hooked on to a charger (because then you have all the power you want) and not if you are not hooked to a charger (in which case the car has sufficient power in it's batteries) . But feel free to put it there if you want to...
you cannot preheat the car if its less than 20% in the model 3. it will just refuse to work. and camp mode & co do not work either. if you go to bed the heating will not automatically activate. im not sure what you are on about. the only thing which works is to have the car alert and active but this only lasts around 30min.