Underwhelming cold weather performance

[Blu-Ion]

More tests

I tried to drive with manual heating set to fan level 1 at 19C and recirculate on. Didn't make much difference on energy meter vs automatic just slightly better but windows started fogging up after a while, so back on auto and immediately the fog dissipated.
Here are 2 separate drives with no climate on, just heated seat. The efficiency is awesome as you see. I can definitively conclude that heater is the cause of poor range performance in winter, not lack of regen, nor cold batteries

 

[puzz1ed]

Are Model S and X any different wrt cold weather range loss? I'm also quite surprised by how much the heater affects range.

 

[pcons]

Are Model S and X any different wrt cold weather range loss? I'm also quite surprised by how much the heater affects range.

Should be similar. Because they are both less efficient than the 3 overall, as a proportion the extra loss due to heat will be slightly less noticeable, but still quite dramatic.

 

[pcons]

More tests

I tried to drive with manual heating set to fan level 1 at 19C and recirculate on. Didn't make much difference on energy meter vs automatic just slightly better but windows started fogging up after a while, so back on auto and immediately the fog dissipated.
Here are 2 separate drives with no climate on, just heated seat. The efficiency is awesome as you see. I can definitively conclude that heater is the cause of poor range performance in winter, not lack of regen, nor cold batteries

Nice tests. I do agree with your observations. So a bit surprised without heat you got numbers that good, even taking into consideration you have a RWD. I'm assuming that wasnt highway driving and you were mostly at around 60-70 km/h?

For sure my experience has been the same in that heating takes up much more energy than loss of efficiency due to cold. However even without heat there is a 10%-ish range loss due to colder (more dense) air as well as more friction in the drive train and stickier winter tires...I spent a few winters with a heated blanket and no heat in my first volt to avoid burning dino juice . Add heat and you will lose another 20-30%.

 

[navguy12]

More tests

I tried to drive with manual heating set to fan level 1 at 19C and recirculate on. Didn't make much difference on energy meter vs automatic just slightly better but windows started fogging up after a while, so back on auto and immediately the fog dissipated.
Here are 2 separate drives with no climate on, just heated seat. The efficiency is awesome as you see. I can definitively conclude that heater is the cause of poor range performance in winter, not lack of regen, nor cold batteries

@Blu-Ion, I'm the lone dissenter in all of Tesla Land that feels battery conditioning does play some sort of roll in the energy used during cold weather ops in the TM3.

Your tests that you detailed here, were there any "regen limited" dots showing?

My only reason for still clinging to the battery conditioning line of thought: once my regen limited dots go away, I can discern when the HVAC is no longer piping toasty hot (with resistance heat) air flow but is siphoning off "warm" scavenged heat from a different source.

I keep the fan at speed "1", so the HVAC never catches up with the call for heat.....thus it always is pumping hot air out of the selected outlets (even at 18c as my set point).

Thoughts?

 

[Funkmobile]

@Blu-Ion, I'm the lone dissenter in all of Tesla Land that feels battery conditioning does play some sort of roll in the energy used during cold weather ops in the TM3.

Your tests that you detailed here, were there any "regen limited" dots showing?

My only reason for still clinging to the battery conditioning line of thought: once my regen limited dots go away, I can discern when the HVAC is no longer piping toasty hot (with resistance heat) air flow but is siphoning off "warm" scavenged heat from a different source.

I keep the fan at speed "1", so the HVAC never catches up with the call for heat.....thus it always is pumping hot air out of the selected outlets (even at 18c as my set point).

Thoughts?

There's a lot of variables in play so your experience with higher energy consumption is based on your driving style and routes. Some variables will stand out more than others based on that.

 

[Blu-Ion]

Nice tests. I do agree with your observations. So a bit surprised without heat you got numbers that good, even taking into consideration you have a RWD. I'm assuming that wasnt highway driving and you were mostly at around 60-70 km/h?

Yes highway driving in medium traffic, max set on AP at 106km/hr, some parts at standstill, some at 60-80, some at full speed.

I measured by commute this morning and got 143wh

 

[Iceman8]

In my tests, I also found that the heater had a big impact on the range. With the outside temperature around 0-10 degrees, I found that going from 20 degrees to 17 degrees made my efficiency go from close to 200 wh/km to closer to the rated 145 wh/km. I didn't record anything, so these are very un-scientific results, but I did find that I could still get the rated range when outside temperatures were close to 0.

I find that now with temperatures < 0 degrees, my efficiency sits closer to 170-180 wh/km, so I definitely see an impact due to the temperature as well.

Although having the temperature set at 17 degrees isn't ideal, I've gotten used to it.

 

[navguy12]

Yes highway driving in medium traffic, max set on AP at 106km/hr, some parts at standstill, some at 60-80, some at full speed.

I measured by commute this morning and got 143wh

Wow, that does sound like summer numbers for me.

I guess I'll have to try a run with no heat being called for and see what numbers I get.

We have a cold event coming soon (expect high is -17c) and I'm tempted to park the car outside and let it cold soak, plug it in without any demand for heat and see if the cold soaked battery will draw juice from the wall for the sake of battery conditioning.

I have a separate meter on that circuit so it is easy to measure.

 

[Birdman325]

Here are some results I did from a very unscientific informal test back in early Dec. (I posed this previously in another forum but thought it might be interesting to add to the discussion).

-------

- LR AWD Model 3 currently running on the 18” Aero winter package.
- Most mornings I do the same drive - first I drive my son to school, and then I head down to work. The drive from my son’s school to my office in downtown Toronto is apx. 17.6 km (just shy of 11 miles) and is probably net downhill. I also keep the HVAC on manual, fan speed at 2, and temp at 18.5 C (65.3 F).
- I didn’t drive last Friday but I did on Thursday and the weather was very similar to this morning. Dry and about 4 degrees Celsius (apx 39 degrees F).
- Driving relatively conservative, I typically can get to an average of about 215- 220 wh/Km on the way down to the office (apx 354 wh/mile).
- This morning, the only difference was I turned off the HVAC entirely and set the seat heaters to the 2nd level.
-It definitely was getting uncomfortably “cool” in the car, and the windows (side and rear especially) were becoming quite foggy. But...I ended up pulling into parking with the trip meter showing 119 wh/km! (17.6 km, 37 minutes, 119 wh/km - apx. 191 wh/mile).

To summarize
- Using the heater - 220 wh/Km (354 wh/mile)
- Not using the heater 119 wh/Km (191 wh/mile)

 

[Iceman8]

Wow, that does sound like summer numbers for me.

I guess I'll have to try a run with no heat being called for and see what numbers I get.

We have a cold event coming soon (expect high is -17c) and I'm tempted to park the car outside and let it cold soak, plug it in without any demand for heat and see if the cold soaked battery will draw juice from the wall for the sake of battery conditioning.

I have a separate meter on that circuit so it is easy to measure.

oh nice, yeah, definitely run some tests like that.

I'd try having no heat vs. using just seat heaters vs. just heaters to see how your range is affected. Just bundle up a bit when you try that out!

it hasn't gotten too cold where I am just yet, so it'd be interesting to see how much of a hit the range takes when temperatures get down to the -20's.

 

[navguy12]

Just bundle up a bit when you try that out!

Oh yea, I don't mind science experiments but I'm not gonna be goofy about it

 

[Darscot]

One thing I would love to see added to the Model 3 is super efficient no heat defrost. I tend to disable AC turn temp to low and fan to 1 with just the windshield. I toggle this on and off every few minutes. I don't mind the cold (well west coast cold) but the trying to keep the window clear I feel like I'm back in an air cooled VW. No heat and my efficiency is still very good.

 

[mswlogo]

If you're wanting regen for energy savings....yeah, that's usually going to be a net waste. However, for those who are interested in maximizing the range they're able to drive as opposed to minimizing their total net electricity consumption, it's an advantage. Also if you're doing it so that the car's driving behavior is always roughly consistent--this makes driving safer--then a net energy loss isn't really relevant. Or, if you are starting your drive with a decent downgrade distance, pre-spending the electricity to warm up the battery enough to enable regen could actually be a net positive for total consumption. All these things are context and circumstance dependent.

This comes up in the context of their daily routine. Nobody would question it, if it's strictly to get max range.

If it's that cold that they lose regen every night and it's a constancy thing. They will lose it again typically when they leave work. So now your morning commute will be different than evening. If consistency is an issue then set it to low regen.

If I have say 15 dots and charge at home for hour in that state, I'm luck if it removes 2 dots. I only charge on a 30A circuit though, perhaps folks with 60A setup would allow more efficiency.

It's like p$ssing into the wind trying to keep your battery warm.

 

[mswlogo]

Here are some results I did from a very unscientific informal test back in early Dec. (I posed this previously in another forum but thought it might be interesting to add to the discussion).

-------

- LR AWD Model 3 currently running on the 18” Aero winter package.
- Most mornings I do the same drive - first I drive my son to school, and then I head down to work. The drive from my son’s school to my office in downtown Toronto is apx. 17.6 km (just shy of 11 miles) and is probably net downhill. I also keep the HVAC on manual, fan speed at 2, and temp at 18.5 C (65.3 F).
- I didn’t drive last Friday but I did on Thursday and the weather was very similar to this morning. Dry and about 4 degrees Celsius (apx 39 degrees F).
- Driving relatively conservative, I typically can get to an average of about 215- 220 wh/Km on the way down to the office (apx 354 wh/mile).
- This morning, the only difference was I turned off the HVAC entirely and set the seat heaters to the 2nd level.
-It definitely was getting uncomfortably “cool” in the car, and the windows (side and rear especially) were becoming quite foggy. But...I ended up pulling into parking with the trip meter showing 119 wh/km! (17.6 km, 37 minutes, 119 wh/km - apx. 191 wh/mile).

To summarize
- Using the heater - 220 wh/Km (354 wh/mile)
- Not using the heater 119 wh/Km (191 wh/mile)

I've tried exactly that as well and totally agree (on AWD). I bet your regen didn't matter much either.

The problem isn't freezing your butt off with "alternative" heat methods (including none) it's the damn fogging.
So I tried to focus on reducing fogging so I could run the HVAC with no A/C and recirculate.
So far the results are pretty positive. 232 wh/mile with heat on 68, no regen, 28F and AWD (not extremely cold though).

Check out this thread I created on it.

A clean windshield can decrease your wh/mi

 

[Funkmobile]

This comes up in the context of their daily routine. Nobody would question it, if it's strictly to get max range.

If it's that cold that they lose regen every night and it's a constancy thing. They will lose it again typically when they leave work. So now your morning commute will be different than evening. If consistency is an issue then set it to low regen.

If I have say 15 dots and charge at home for hour in that state, I'm luck if it removes 2 dots. I only charge on a 30A circuit though, perhaps folks with 60A setup would allow more efficiency.

It's like p$ssing into the wind trying to keep your battery warm.

To complicate matters is that the Model 3 motor will automatically run inefficient to generate heat (up to 2kW) in order to warm up the battery/drivetrain while you are driving. So either way you are actually "spending" electricity to warm up your battery either by directly "wasting" energy at home by preheating your battery or indirectly "wasting" energy by burning more via your drive.

In that scenario I would rather preheat the battery and have that regen and save on brakes.

 

[mswlogo]

To complicate matters is that the Model 3 motor will automatically run inefficient to generate heat (up to 2kW) in order to warm up the battery/drivetrain while you are driving. So either way you are actually "spending" electricity to warm up your battery either by directly "wasting" energy at home by preheating your battery or indirectly "wasting" energy by burning more via your drive.

In that scenario I would rather preheat the battery and have that regen and save on brakes.

There is no evidence of that at all. It might if a snow flake is visible.
I've gone 72 miles without full regen when it was like 10F out (started trip with a snowflake).

I've also had the heat Off, no regen, pull out of garage and immediately get 230 wh/mi on AWD in 20F range.
If it was actively heating the battery while I drive I would never get that.

The only time I think it will heat battery (via motors) is during charging or protect the battery from damage (which is only when it way low in temps).
It will never heat the battery just to get regen (it knows that's a lost cause).
And if it was worth heating the battery to get regen, it would do it !!

 

[Funkmobile]

There is no evidence of that at all. It might if a snow flake is visible.
I've gone 72 miles without full regen when it was like 10F out (started trip with a snowflake).

I've also had the heat Off, no regen, pull out of garage and immediately get 230 wh/mi on AWD in 20F range.
If it was actively heating the battery while I drive I would never get that.

The only time I think it will heat battery (via motors) is during charging or protect the battery from damage (which is only when it way low in temps).
It will never heat the battery just to get regen (it knows that's a lost cause).
And if it was worth heating the battery to get regen, it would do it !!

The heat generation is up to 2kW, not 2kW full blast 24/7. And yes, if it's cold enough, you will not get full regen but you still have more regen than if the battery was dead cold.

Regen alone is not enough to heat up the battery in any significant manner (i.e. the percentage of time you are actually regenerating vs you are pressing the go pedal is very small.) You can see this by just charging your car and seeing how much regen you get back. It takes a full 10kW for an hour for me to get a significant amount of regen back from a cold battery. That's 10kW full blast. How much time do you figure your car is regen mode on a 30-60 minute drive?

Therefore, that heat must be generated by the motor itself. The amount of heat generated is of course up for speculation. I would speculate the motor only generates heat when it is under load (i.e. pressing down on the go pedal).

My point still stays the same, you can either spend the energy at home or on the road.

 

[bijan]

The heat generation is up to 2kW, not 2kW full blast 24/7. And yes, if it's cold enough, you will not get full regen but you still have more regen than if the battery was dead cold.

Regen alone is not enough to heat up the battery in any significant manner (i.e. the percentage of time you are actually regenerating vs you are pressing the go pedal is very small.) You can see this by just charging your car and seeing how much regen you get back. It takes a full 10kW for an hour for me to get a significant amount of regen back from a cold battery. That's 10kW full blast. How much time do you figure your car is regen mode on a 30-60 minute drive?

Therefore, that heat must be generated by the motor itself. The amount of heat generated is of course up for speculation. I would speculate the motor only generates heat when it is under load (i.e. pressing down on the go pedal).

My point still stays the same, you can either spend the energy at home or on the road.

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.

 

[5_+JqckQttqck]

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.