Tesla Owners in Alberta

[green1]

It's all a mater of time. In an hour outside the vehicle would normally have retained a fair amount of heat, and the wind removing some of that means you have to heat it up again. But in a full day sitting, the vehicle has likely gotten itself down to ambient temperature either way, and the wind can't take it below that. Wind affects speed of cooling, not how cold it gets.

 

[Doug_G]

Okay... we're not disagreeing.

 

[green1]

Okay... we're not disagreeing.

It's an important distinction though, because I hear people quote the wind chill "temperature" all the time when talking about things other than warm blooded creatures. And it is simply not accurate, people think that a car sitting for a week at -20 with a windchill of -35 will have a harder time starting than one sitting for the same time at a temperature of -20 with no windchill. People need to understand that in both cases the vehicle is at -20, it never gets below that.

I don't know how long it takes to cold-soak a Model S battery pack, but given it's exposed nature, and it's large surface area to volume ratio, I doubt it holds heat any longer than an ICE engine block, and I've found those seem to retain some heat in no wind situations for only about 4-6 hours at -20 after that you could sit for a couple hours or a week and it won't get any colder. Which means when running errands wind chill matters, when parking for a normal 8 hour workday, it's likely irrelevant.

 

[Doug_G]

I agree it's a distinction that is important - but again I was being specific about that Nevertheless wind effects are relevant.

Yes if it's a cloudy day with no temperature changes, after 8 hours it probably doesn't matter if there was wind. But it was a sunny day and then the temperature drops (not uncommon when the sun goes down) then wind can still have a significant impact on the final pack temperature.

If you are parking for a shorter period of time, then wind has an immense impact. If you park for an hour on a cold but sunny and calm day, you'll have a mild regen limit. If you park for an hour in the same conditions but with strong winds, you could have no regen and a power limit. The pack has a LOT of exposed area underneath. That's why the Roadster stays warmer longer; its box-like battery pack has much less exposed area for its volume.

I've found that in extreme cold (-20C and below) the battery pack never reaches normal operating temperatures, even after hours of driving on the highway. The cooling slipstream under the car still chills out the pack. I've driven on the highway for over two hours, then parked and had the car immediately pop the warning about plugging in because the pack is cold.

 

[green1]

I've found that in extreme cold (-20C and below) the battery pack never reaches normal operating temperatures, even after hours of driving on the highway. The cooling slipstream under the car still chills out the pack. I've driven on the highway for over two hours, then parked and had the car immediately pop the warning about plugging in because the pack is cold.

I do sometimes wonder if basing an automaker in California leads to some tradeoffs that are more beneficial to a warm climate than a cold one...

 

[m1ker]

I agree it's a distinction that is important - but again I was being specific about that Nevertheless wind effects are relevant.

Yes if it's a cloudy day with no temperature changes, after 8 hours it probably doesn't matter if there was wind. But it was a sunny day and then the temperature drops (not uncommon when the sun goes down) then wind can still have a significant impact on the final pack temperature.

If you are parking for a shorter period of time, then wind has an immense impact. If you park for an hour on a cold but sunny and calm day, you'll have a mild regen limit. If you park for an hour in the same conditions but with strong winds, you could have no regen and a power limit. The pack has a LOT of exposed area underneath. That's why the Roadster stays warmer longer; its box-like battery pack has much less exposed area for its volume.

I've found that in extreme cold (-20C and below) the battery pack never reaches normal operating temperatures, even after hours of driving on the highway. The cooling slipstream under the car still chills out the pack. I've driven on the highway for over two hours, then parked and had the car immediately pop the warning about plugging in because the pack is cold.

Doug_G, does it just have to heat the battery a bit before it begins charging? And how long does it take to get the battery temp to a point it's ready to begin charging?

 

[Doug_G]

Doug_G, does it just have to heat the battery a bit before it begins charging? And how long does it take to get the battery temp to a point it's ready to begin charging?

Yes. The battery needs to be above freezing in order to charge; otherwise it would be damaged. So if your battery is cold soaked the 6 kW battery heater runs at first, then as it warms up it starts pumping current into the cells. No doubt the charging current then helps keep it warm. (I'm pretty sure it actually starts charging below freezing at a very slow rate and then ramps it up as the temperature increases, but it's difficult to say for sure because they don't give you the battery temperature.)

This is the reason why charging with 110V doesn't work at extremely low temperatures. That's only 1.2 kW and not enough to warm up the pack.

How long it takes depends on the temperature (and no doubt wind). I've not timed it, but it can take 20 minutes.

 

[Mayhemm]

I've found that in extreme cold (-20C and below) the battery pack never reaches normal operating temperatures, even after hours of driving on the highway. The cooling slipstream under the car still chills out the pack. I've driven on the highway for over two hours, then parked and had the car immediately pop the warning about plugging in because the pack is cold.

I was actually going to start a new thread on this topic. It's been crazy cold the last couple weeks (sounds like most of the country is getting it) and my car is regen (sometimes even power) limited when I set off each day despite pre-heating for 20 to 30 minutes. Are you saying that when it's below -20 like it has been the regen/power limits may never clear? I'm primarily driving in town, not on the highway.

 

[tomanik]

I was actually going to start a new thread on this topic. It's been crazy cold the last couple weeks (sounds like most of the country is getting it) and my car is regen (sometimes even power) limited when I set off each day despite pre-heating for 20 to 30 minutes. Are you saying that when it's below -20 like it has been the regen/power limits may never clear? I'm primarily driving in town, not on the highway.

If you can, schedule your charging so that it ends near your departure time each morning. This should leave you with a warm battery for the morning commute and only a reduction in regen power at most. If you do not have range mode enabled then the car should be able to warm/keep the battery warm enough while you are driving to remove the power limits and offer some regen.

 

[Zapped]

I assume that shore power would start the heat/cooling pump or if it's continuously plugged in, maintain the battery temp to some degree

 

[Mayhemm]

If you can, schedule your charging so that it ends near your departure time each morning.

This is difficult since I don't always know that much in advance when I'll need to leave.

I assume that shore power would start the heat/cooling pump or if it's continuously plugged in, maintain the battery temp to some degree

Yes, the battery heater will kick in to prevent the cells from becoming too cold. Users have no control over this and it will result in greater-than-normal power use if the vehicle is not plugged in. I'm not sure whether that power is drawn from the wall when the car is plugged in though. I've seen up to a 20km loss from my set charge limit on really cold nights even when the car's plugged in. It doesn't seem to top itself up automatically when this happens either.

 

[clea]

This is difficult since I don't always know that much in advance when I'll need to leave.

One trick a few of us used last year was to restart a charge around the same time before leaving as you would to preheat the car. To do this you simply change to range mode charge but you leave long before it finishes ...

 

[Grassy Knoel]

I don't expect my limited regen to go away until April. Every day last winter I was greeted by the yellow dashed lines, even with pre-heating. The positive spin is that it was consistent behaviour , as opposed to some days with full regen and some with limited.

 

[3s-a-charm]

Rough install of my HPWC completed. Too bad I had to have the massive shut-off switch so close by. I was told it was code because it is so far from the panel and the panel is not considered a shut-off. Managed to get a full 100 Amp connection so looking forward to fast charging with the dual chargers - 92km of range per hour of charing. Looking forward to finishing off the drywall and finally getting the car installed in my garage!

 

[Doug_G]

Yeah the shutoff thing is a bit of a nuisance - the shutoff is bigger than the EVSE.

Our local utility is dumb. They require a cutoff switch for the NEMA 14-50 outlet if you're going to use it for an EV. Obviously the PLUG lets you disconnect the UMC, but they'd have none of it.

It's due to a misinterpretation of the electrical code, IMHO... I brought it up with the inspector but he insisted on his interpretation of course. Then he said, "what if the operator doesn't think to unplug the car first before the NEMA 14-50 - they could draw a nice arc. The switch will prevent that." My response: "If they're too clueless to disconnect the car first, it's pretty certain they're not going to flip that switch either!!!"

So now I have a nice cutout switch in case anyone ever wants to work on the NEMA 14-50. But if someone ever wants to work on the cutout switch... maybe we should have switches going all the way back to the panel!

On the bright side, it's a handy holder for the Tesla plug!

 

[gpetti]

Rough install of my HPWC completed. Too bad I had to have the massive shut-off switch so close by. I was told it was code because it is so far from the panel and the panel is not considered a shut-off. Managed to get a full 100 Amp connection so looking forward to fast charging with the dual chargers - 92km of range per hour of charing. Looking forward to finishing off the drywall and finally getting the car installed in my garage!
View attachment 64976View attachment 64977

That is exactly what mine looks like now. Originally the electrician left the shut off switch out and it didn't meet code.

 

[3s-a-charm]

Ok... garage ready. Just need my Tesla to arrive. :love:

 

[Mayhemm]

Electrician didn't put a cut-off switch on my HPWC; presumably since it is only 3 feet from the panel. Haven't had it inspected yet.

 

[m1ker]

Ok... garage ready. Just need my Tesla to arrive. :love:

3s-a-charm, when is your expected delivery date? We just received a note that we are in mid march, and the delivery guy asked us for dates we might be away. I'm still hoping they can get it to us sooner, rather than later.

 

[Doug_G]

Electrician didn't put a cut-off switch on my HPWC; presumably since it is only 3 feet from the panel. Haven't had it inspected yet.

That's okay, because the cutoff switch (the breaker) is within eyesight of the HPWC.

The rule is so that electricians can work on the gadget without being electrocuted. 240V/100A is enough power for a fairly serious arc flash.