Underwhelming cold weather performance

[pcons]

Been booting around in a 75D Black rental - will post story later from a hit and run - car in the shop.

With Aeros... the 75D is pretty close to RWD in terms of efficiency with non-aero rims. Lots of factors at play here: non-OEM rims are a culprit also to poor winter numbers.

Damn, sorry to hear about the hit and run. Interested in details.

Also interesting the 75D is close to RWD. The car is heavier with different batteries, and I thought the model 3 was supposed to be much more efficient (esp the RWD model 3) than the S since I believe the 75D is rated for ~ 400km while the 3 LR (with also a ~ 75 kWh battery) is rated for 500 km, and the RWD actually gets closer to 530km.

 

[5_+JqckQttqck]

Damn, sorry to hear about the hit and run. Interested in details.

Also interesting the 75D is close to RWD. The car is heavier with different batteries, and I thought the model 3 was supposed to be much more efficient (esp the RWD model 3) than the S since I believe the 75D is rated for ~ 400km while the 3 LR (with also a ~ 75 kWh battery) is rated for 500 km, and the RWD actually gets closer to 530km.

My winter wheels are heavy

 

[Funkmobile]

Yes but on the road does not mean it is all extra waste heat that wouldn't be generated anyways. The motor running normally also generates heat. It's consuming 150wh/km so about 15kWh per 100 km, so depending on efficiency some of that can go to warming the battery. If motor is 80% efficient that would be 3kWh of heat which would be generated whether you preheat or not plus the theoretical 2kWh maximum of extra heat generation that we might also get.

That's 150wh/km with all the HVAC, lights, MCU, power steering, pumps etc running.

Also according to this: https://www.researchgate.net/public...ncy_Analysis_of_Synchronous_Reluctance_Motors

Reluctance Motors motors run around 92% efficient at speed. Assuming Tesla just matches that 2013 paper that means only 8% or less is generated as heat. Assuming 80% total power is going towards the motor that's 12kWh spent on the motor itself. 8% inherent inefficiency = 0.96kWh generated over a 100km trip.

According to TeslaFI, I know when I charge at home in the current weather in Vancouver, I'm charging at about 70% efficiency. Over an hour @ 10kW means I'm wasting about 3kWh each hour which presumably is wasted heating up the battery while charging.

Assuming both trips result in the same amount of regen levels at the end, that means about 2kWh is unaccounted for in the cold battery driving scenario.

 

[Funkmobile]

Been booting around in a 75D Black rental - will post story later from a hit and run - car in the shop.

With Aeros... the 75D is pretty close to RWD in terms of efficiency with non-aero rims. Lots of factors at play here: non-OEM rims are a culprit also to poor winter numbers.

Sorry to hear that , how long's the wait for parts?

 

[5_+JqckQttqck]

Sorry to hear that , how long's the wait for parts?

Five to six days at Excellence in Scarborough. Front driver side panel fix / repaint / PPF (PPF saved the door but probably extended repair times?)

 

[navguy12]

Today I test drove my normal 14 km loop without the heat on.

What has proven to be a 170 wh/km trip during the winter returned 135 wh/km.

This was at -2c indicated.

Tonight, while detailing my car in my garage (ambient temperature 8c) I figured to run a little experiment after TOU rates changed at 1900 this evening.

My wall connector circuit has a seperate meter, so I turned on the HVAC to my normal setting (18c, fan on 1, fresh air only, etc).

The car pulled 7.1 kW of power and then settled around 6.0 kW after five minutes.

One could construe a 100 wh/km penalty at 100 kph for heating the car from the above data point.

Funny thing happened when I ended the test and turned off the HVAC.

The car continued to draw 2.5 kW of power from the grid.

HVAC was off.

My scheduled recharge time is not set to start until 0430 and I have it set for the full 48 amps.

After another 10 minutes of this power going "somewhere", I momentarily disconnected the charge cable to stop the power flow.

Upon reconnecting, the system went back to normal, which is the 4 watt draw for the wall connector itself.

The battery level remained at 53%......

Was this inadvertently charging the battery or was this battery conditioning?

 

[Blu-Ion]

Extra cold -18C commute this morning
AP set at max 106km/hr, medium traffic conditions
climate set at manual 1 all 3 zones, 19C
driver heated seat at 2
result: 203wh

In the past I left it in auto, I would get 240-250 when it wasn't as cold, say -5C.

So, in order to maximize range, you must must not leave climate on Auto setting

 

[navguy12]

So, in order to maximize range, you must must not leave climate on Auto setting

Absolutely agree.

Do you use re-circulate with A/C compressor on?

I leave the A/C off but fresh air only as the dry cold air has no issue keeping the interior glass clear.

 

[lotuni]

Extra cold -18C commute this morning
AP set at max 106km/hr, medium traffic conditions
climate set at manual 1 all 3 zones, 19C
driver heated seat at 2
result: 203wh

In the past I left it in auto, I would get 240-250 when it wasn't as cold, say -5C.

So, in order to maximize range, you must must not leave climate on Auto setting

Agree been doing tests as well lately, here is a rough summary.

Today was -20 and did a 61 km trip to the airport, heat at 21 and 2 front seats at 2 bacon strips. Usage was 253 at about 105 km/hr. Using manual heat settings at 2 fan and 21c I get about -180-200.

I also tried a granny hype mile with no heat and no seats at city speeds 50-60 at about -18c and was able to get ~120 usage.

Moral of the story as many have stayed, the heater consumes a lot of energy and model 3 is not a fan of anything under -5c.

 

[Blu-Ion]

Absolutely agree.

Do you use re-circulate with A/C compressor on?

I leave the A/C off but fresh air only as the dry cold air has no issue keeping the interior glass clear.

Fresh air (my previous test used recirc earlier in this thread and fogged after a while), no AC

 

[ElectricCanada]

If people really miss their re-gen and don't mind using power, turn on the climate for an extended period of time (45-60 minutes) before going out. I have done that a couple of times accidentally when it was -18C and -13C, thought I was going out to the car but then got held up for various reasons. Used between 4-5% of the battery but had 1/3 to 1/2 regen available. Snowflake was on battery before turning on climate, and gone by the time I got into the car.

 

[ctrystruha]

If anyone was wondering what -25C (-35 with windchill) temperatures do to a model 3’s battery here is a nice picture to sum it up:

- 9% battery in frozen state.
- No regen at all.
- Performance severely limited (had to be careful this morning).
- All indicators taken after warming/sitting on the charger for 20 minutes.

 

[bijan]

If anyone was wondering what -25C (-35 with windchill) temperatures do to a model 3’s battery here is a nice picture to sum it up:

- 9% battery in frozen state.
- No regen at all.
- Performance severely limited (had to be careful this morning).
- All indicators taken after warming/sitting on the charger for 20 minutes.

I've gotten very similar state (no regen, dots on the right) from leaving the car outside at -13C, and not preheating. Hasn't gotten much colder here, Sunday might go below -20C though.

 

[duanra]

Thanks for the info. Although i am not sure the wind makes any difference for the car.

 

[mociaf9]

Thanks for the info. Although i am not sure the wind makes any difference for the car.

It will (minorly) impact the time it takes to heat/warm up while the car is sitting still. Probably no temperature impact while in motion, only range/efficiency impacts based on wind speed and direction.

 

[duanra]

My understanding is that the wind chill affects only live skin.
Friction of the wind on a surface will actually increase the temperature of the surface.
One can see that on jets.

 

[ctrystruha]

My understanding is that the wind chill affects only live skin.
Friction of the wind on a surface will actually increase the temperature of the surface.
One can see that on jets.

Fair enough, just wanted to express how grossly cold it is here today!

 

[duanra]

I hear you, it is going to be -20c tonight...not looking forward to.

 

[navguy12]

If anyone was wondering what -25C (-35 with windchill) temperatures do to a model 3’s battery here is a nice picture to sum it up:

- 9% battery in frozen state.
- No regen at all.
- Performance severely limited (had to be careful this morning).
- All indicators taken after warming/sitting on the charger for 20 minutes.

Was this after you had pre set 80% as the "charge to" level?

If so, good to know for future cold ops charging protocols.

 

[bijan]

My understanding is that the wind chill affects only live skin.
Friction of the wind on a surface will actually increase the temperature of the surface.
One can see that on jets.

Also when traveling 100km/h with no wind you get 100km/h worth of windchill anyways from the air you're zipping through.