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We live around Atlanta and we were hit with 2-3 inches of snow on Tuesday. The entire city shut down and people were stranded on the highway for 12+ hrs in some cases. My coworkers took 13 hrs to get home which would normally take 40 minutes.

Instead of leaving early at 1 on Tuesday, I worked until around 6, and decided to try to wait out the traffic. I had left my house in the morning with only 1/4 tank in my ML63 so knew I would run out in a traffic jam.

Some people eventually gave up trying to get home and returned to the office around 10pm. I ended up sleeping on the floor until 4:30am and then headed out after the Waze reports died down. Still there were a lot of jams around the highways. I was able to take snowy residential back roads to avoid jams, but a couple times I was surprised the car didn't get stuck going uphill. Last year I went from summer tires to Continental DWS which helped I think.

So my question, if I didn't have my Ml63 and had to drive my Smart home and got stuck, how long can I run the heater to keep the car a minimum of 50 or 60 degrees F? Assuming a full charge.

I would probably try to just run the seat heaters, but I doubt that would be enough with air temperatures around 11 degrees F. I also didn't have a heavy jacket on since I normally drive from the garage at home to the garage at work and take the elevator.

I'm thinking of keeping a 12v electric blanket in the car just in case. It would draw 80watts.
 

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Keep a set of warm clothes in the car when this type of weather is forecast. I also keep emergency food and water in my car throughout the "real" ;) winter. I would bundle up and only use enough heat to keep the windows clear. Can you charge the ED at your work?

I can not fathom how a 40 minute drive can turn into a 13 hour ordeal. 8 years ago all the roads were closed for most of the region up here, my 50 minute drive took about 3 hours. Much of the drive was running only a little above idle speed, due to lack of visibility.

Ideally best just to stay home I think.
 

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I just used the heater once for about 20 minutes. Since I noticed that spends about 5% more battery I just wear a thicker jacket. No need for a heater in California.
 

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Keep a set of warm clothes in the car when this type of weather is forecast. I also keep emergency food and water in my car throughout the "real" ;) winter. I would bundle up and only use enough heat to keep the windows clear. Can you charge the ED at your work?

I can not fathom how a 40 minute drive can turn into a 13 hour ordeal. 8 years ago all the roads were closed for most of the region up here, my 50 minute drive took about 3 hours. Much of the drive was running only a little above idle speed, due to lack of visibility.

Ideally best just to stay home I think.
Fathom? Remember, these people do not drive on snow or ice... So imagine: glaze ice, snow on top and just enough hills and tractor trailers to block all exits of a high volume expressway system with all businesses and schools closing and letting out at the same time. This is America's ninth largest city, with minimal mass transit. Cars are key. This happens so rarely that they don't recognize the need to sand and salt the hills first, nor are wreckers on standby for the big rigs that block the hills. It would be wise in weather emergencies like this for the big rigs to be sidelined until the auto traffic clears. Just my 2 cents.
So, who recessed hell?
Kroger grocery stores opened their doors to stranded school bus loads of teenagers and invited them to get what they desired from the shelves. Nice gesture. The teens had been on the bus for hours.
 

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how long can I run the heater to keep the car a minimum of 50 or 60 degrees F? Assuming a full charge.
Tough to answer that question exactly until you tried, but here's some numbers to bracket what you can expect:
At full blast, the heater uses 5kW. (fan and temp on max) That would drain a full battery in just over three hours. But it also will make the car very hot, at least 40C or 70F over ambient (I tried). If you turn the fan down you can maintain the same temperature with less power, and you won't want it to be that hot anyway, so the battery can likely last 3-4 times as long.

I would probably try to just run the seat heaters
Now that's the better idea all around. The seat heater uses a fraction of the power, and makes the seat very hot in a short time. You'll be comfortable with a much lower cabin temperature. Just too bad you can't set the thermostat any lower than 60.
 

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At full blast, the heater uses 5kW. (fan and temp on max) That would drain a full battery in just over three hours.
5kW is much more than I thought, for some reason I thought it was more like a conventional home space heater around 1,500 watts. 5kW is more like the auxiliary coils on a home heat pump.
 

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ED stuck in Atlanta Snowmagedden v.2014 with freezing temperatures and 2-3 inches of snow/ice . . . :bangwall: :surrender: :mad:

Advantage - ICE! :shrug:

Heater blowing AND bun warmers toasty!
 

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Up North we usually dress or carry clothing appropriate for being in a car that will not run. things like hats gloves coats and regular blankets can make a big difference in the cold. The illusion we control everything is just that.
 

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Let's face it, the Georgia snow response was abysmal. Planning seemed to be minimal and execution was too little, too late. Hopefully those in a position to change things learned a lesson, and the average citizen got a better appreciation of the phrase "Don't mess with Mother Nature." :)
 

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In Atlanta where the coldest month in 2013 was February with an average daily low temperature of 38°F, really hard to plan and have resources in place for that 10 year snow/ice storm?

Stuff happens and then it snows . . .
 

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I have been experimenting with the ED heater, and have found...

When you turn on the fan (anything other than off), the range estimate seems to drop a fixed amount (about 8-10KM for me). It doesn't matter how fast you've set the fan or what temperature you've set. As a matter of fact, even if the temp is set to ZERO (no heat) but the fan is running, the range comp drops the 8-10KM no matter what. I think the range comp simply guesses since the heater system is on (fan not set to off).

So, I ignored the range comp and used the gauge that shows current draw. I started the car, turned EVERYTHING off, and the gauge shows a hair above zero. Ok, this is my ZERO calibration.

Now, if I turn on the fan (any speed) with the temp set to ZERO (no heat), the gauge barely registers anything - this means the fan itself does not draw any significant current.

Next, set fan low, set temp to lowest setting (18C). Now the current gauge registers a noticeable current draw. As I slowly increase the fan speed to max, I notice the current draw goes up a bit for each fan speed setting. Since the fan itself does not register any significant current draw, this means the PTC heater itself is scaling it's current needs based on fan speed (the higher the fan speed the more current the PTC header draws).

Also, setting a higher temp setting cause more current draw (until cabin temp is reached). It seems the PTC heater draws more current if you ask for a higher temp, probably to help reach the desired temp sooner.

Setting the temp to a reasonable level (say 20C), and letting the cabin heat up and reach the set temp, I notice that the PTC heater now cycles (turns off and on to maintain cabin temp). This means the PTC current draw is not continuous once the desired temperature is reached. In this case, I notice the current draw gauge drop down to near zero for a while while the PTC heater is cycled off. If the cabin cools below set temp then the PTC heater will kick in again and draw more current.

The heated car seats take very little current (as seen on the current gauge) as compared to the PTC heater.

My wife drives the ED mostly, and initially she was very conservative in PTC heater usage (based on the range estimate). I now believe the range estimate is not very accurate with the PTC heater and is probably assuming the PTC heater will be on constantly until the battery is all used up.

Now my wife leaves the temperature set to a reasonable level (18C to 20C) and also relies a bit on the heated seats. Since the PTC heater is cycling it will not be drawing full current for the entire time if the cabin temp makes it to the set temp. Also we leave the fan set to about the middle speed setting.

Before, she was switching off the fan (because of the rough range estimate), but in cooler weather the cabin would cool sooner as now cold outside air as still flowing into the cabin. This could be reduced by switching to RECIRC but that typically causes fogging.

YMMV. :)
 

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In Atlanta where the coldest month in 2013 was February with an average daily low temperature of 38°F, really hard to plan and have resources in place for that 10 year snow/ice storm?

Stuff happens and then it snows . . .
Actually, it isn't - the "planners" in Georgia apparently can't be bothered. :wink:
 

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Actually, it isn't - the "planners" in Georgia apparently can't be bothered. :wink:
Have you ever tried to drive through Atlanta at the posted speed on a clear dry day - same group of "planners" created that quagmire . . .

Same stuff, different day.
 

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I've found that you can eyeball the power consumption based on the difference between cabin temp and the setting on the dash, and watching how much the power gauge moves as you raise it compared to outside temp, I've found that it seems to take about 500W to maintain an inside the cabin to outside the cabin temp difference of 20F (knowing that the PTS heater at the max setting can draw 5kW) sitting in my garage (different than driving down the highway with air flow sucking heat from the car).

Further, it seems the temp lever divides the 5kW into about 10 steps, so that each increase in temp on the dash result in power consumption going up about another 500W (until the set temp is reached, at which point it cycles on and off at the about 500W level).

Observing the sum of mile driven plus range left (I always reset the meter on leaving home so that I can see / calculate this number) heat on, generally equates to a little less that 10% range loss in the morning and half that in the evening when I've already driving half of my 44 mile round trip.

the meter seems to think.... in the morning, if you have 50 miles range left (full battery) and you keep the heat on for that full 50 miles, you give up about 5 miles range. In the evening, if you have 30 miles range left (60% SOC) and you keep the heat on for that full 30 miles, you give up about 3 miles range.

The prediction doesn't matter what the temp setting on the dash is, so it seems the calculation is approximately based on assuming that you will need at most about 40% of the 5kW PTS heater to maintain a comfortable temp in the cabin.

Assuming that 100% SOC = 20kWh, and the PTS heater uses, in the long term, 40% x 5kW = 2kW, that's approximately a 10% loss in range left, if heat is left on full time for a 50 mile trip.

A computer program, would have difficulty predicting with any accuracy, the impact of future heat loss, which would vary with future car and wind speed and outside temperature difference. So I think it just assumes that the car needs about 40% of the 5kW heater to maintain a comfortable cabin setting, in the long term (once you turn it on).
 

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That would drain a full battery in just over three hours.
That's assuming you had 100% and did no driving in that time. But yes, a good ball park. A better way to think of this: With reasonable use (turning it on and off, using recirc and accepting lower temps) you could probably run the heater for an hour easily on about 30% of the charge.

This could be reduced by switching to RECIRC but that typically causes fogging
This mainly causes fogging from the liquid in the car. (Car mats/carpets tend to be the largest culprits, with snow from boots, etc.) Breathing has an effect, but it's minimal by comparison.

One more thing to add to this, is that the PTC draws it's amperage based on several factors. One is air-flow (ie fan setting), but it's also based in part on air temperature going in. This mean using recirc cuts the amount of charge used as well when outside temperatures are very low (below freezing).

We just went through a week plus of single-digit highs here. I spent most of that with the fan on 2 or 3, temp at 70, and toggling the recirc button when the corners of the windshield started to fog vs being totally clear.

I also added a stack of worn towels to my garage, which I use to dry the floor mats in the morning when I first go out (after C&D has melted everything). A quick soak, and the damp towel goes out the window into a garage bin. I can then run the car on recirc for the whole drive in, vs toggling 2 or 3 times on the way. :)
 
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