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Discussion Starter #1
I got stuck in a traffic jam this morning, and luckily, I was stationary for about only 10 minutes.

It got me thinking about the scenario where you might be stuck for an hour or two. What sort of battery percentage might the car use up? I realise that it is dependent upon outside temperature, if the heater and AC is on and the seat heaters etc.

I’m just wondering if this would ever be anything to worry about if I were planning to arrive at a charger and was a bit low.

For example, if I were planning to arrive at a Supercharger with 10-15% battery, would a two hour jam 20 miles away be an issue?
 

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Look up TeslaBjorn on YouTube. He's done some recent tests "camping" in Nordic winter conditions, and calculated battery drain.
 

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For example, if I were planning to arrive at a Supercharger with 10-15% battery, would a two hour jam 20 miles away be an issue?
In short, No.

If you planned to arrive with 5% and got stuck for 5 hours, it would be. Unless you realised how close an issue it was and shut the car off while going nowhere.

Of course you could always stop at a closer non-super charger in that case.
 
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If you planned to arrive with 5% and got stuck for 5 hours, it would be. Unless you realised how close an issue it was and shut the car off while going nowhere.
If you did the same in an ICE I wonder if you'd even last 5 hours..
 

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Discussion Starter #5
Look up TeslaBjorn on YouTube. He's done some recent tests "camping" in Nordic winter conditions, and calculated battery drain.
Thank you @Blurb, I shall. I do watch his videos, but I didn’t bother watching that one because I don’t ever anticipate camping in the car. Of course, being stuck in a traffic jam is the equivalent I suppose.
 

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wit the heating on? probably 1kw per hour at most. with heating off and just listening to music? can probably be there half a day till you lose 1%
 

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Discussion Starter #8
Watched the video. In summary, over 24hrs at sub-zero temperatures overnight, the car lost 100 - 52 = 48% charge. So that’s 2%/hour in those conditions. So, I’d say that’s a handy worst case for most people in the UK.

In my example, that would mean that two hours at a standstill would be no issue whatsoever (arrive with slightly less SoC), but you might start considering options to conserve battery if it were over two hours at a standstill.

Did I miss anything?
 

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Do you guys usually risk arriving at 5%?
I arrived with 1% a couple of weeks ago...not entirely what I planned. I plugged in to the Supercharger and...nothing, tried again charging light flashed a bit and...nothing. Starting to panic massively I moved over to the next charger and it turns out that the one time I had found a broken supercharger unit was the one time I arrived with 1%! Huge relief when the 2nd charger worked I can tell you.
 

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I was stuck in stationary traffic the other day for an hour. Heating on, lost maybe 5 miles of range. Bigger issue was how much more range you lose driving fast afterwards to make up the time!
 

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I got stuck in a traffic jam this morning, and luckily, I was stationary for about only 10 minutes.

It got me thinking about the scenario where you might be stuck for an hour or two. What sort of battery percentage might the car use up? I realise that it is dependent upon outside temperature, if the heater and AC is on and the seat heaters etc.
BEV's use far less energy when idling in traffic and gain a huge range when moving at walking pace as often happens on motorways. Conversely, an ICE's range goes down in heavy traffic and the rather useless stop/start system on newer cars will refuse to do so after about ten minutes as the 12v battery cannot support it along with fan, lights, heated seats, etc..
 

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BEV's use far less energy when idling in traffic and gain a huge range when moving at walking pace as often happens on motorways. Conversely, an ICE's range goes down in heavy traffic and the rather useless stop/start system on newer cars will refuse to do so after about ten minutes as the 12v battery cannot support it along with fan, lights, heated seats, etc..
Not strictly true. BEV cars do consume less than an ICE car but they're still not great at walking pace/ stop start traffic. If you were moving continually at 30 mph then your range would be great. I got stuck in an hour+ tail back in a M3 Performance. crawling along and then sitting for a couple of minutes then crawling along. My energy consumption was running at around 8-900Wh/m which is almost three times more power than travelling at 60-70MPH
 

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Not strictly true. BEV cars do consume less than an ICE car but they're still not great at walking pace/ stop start traffic. If you were moving continually at 30 mph then your range would be great. I got stuck in an hour+ tail back in a M3 Performance. crawling along and then sitting for a couple of minutes then crawling along. My energy consumption was running at around 8-900Wh/m which is almost three times more power than travelling at 60-70MPH
That is very odd as I was stuck in one of my home build EV's in the city one year with black ice everywhere and used far less energy during the journey than I would have done for a quarter of the time. Even accounting for heating although a bit frugal.
Maybe the multiple Tesla computers cooking away behind the scenes make a lot of difference. :ROFLMAO:
 

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I suspect the mass of a 75 kWh pack being accelerated/stopped constantly in stop/start traffic is the issue.
 

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Discussion Starter #15
… it turns out that the one time I had found a broken supercharger unit was the one time I arrived with 1%! Huge relief when the 2nd charger worked I can tell you.
I can imagine. That’s the sort of stress I prefer to avoid and what made me pose the original question.

At the moment, I use ABRP to plan arriving at chargers with 20% left to give me a reserve. I appreciate that this is very conservative, but I’m new to all this EV stuff.

5% seems very risky to me, so I was intrigued to see the notion of planning it.
 

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5% seems very risky to me, so I was intrigued to see the notion of planning it.
You would intentionally do this on longer trips when you know your pack is warm because the charge-curve prefers a mildly low SoC for the best charge rate, On a M3 you should aim for around 10% to maximise rate and lower dwelling times.
 

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What @Slammer said - if you watch some of Bjorn's "1000km" videos he has occasionally planned to arrive at between 5% and 10% in a "long range" EV to maximise charge rate.
20% seems needlessly conservative in a Model 3, so long as there are viable emergency alternatives. In the Leaf 24 I'd plan to arrive at ~15-20% just to give myself a bit of "wiggle room" - but that's likely only 15 miles of actual range remaining even if driving fairly conservatively. In the Model 3, 10% represents at least 20 miles. Unless you're driving in the boondocks (or perhaps in very hilly terrain), where significantly greater margins may be sensible.
 
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