Longer to charge at home in colder weather?

[metroplex]

The ambient temperatures have dipped significantly lower the past few days. It normally took 2-3 hours to charge for my daily drive using 12A/240V (6-15). Just the past 2 days with the ambient temps in the 30F-40F range, I now have to charge it for 4.5 hours. I also hear a lot of different noises during the charging session, something like a compressor followed by a fan at times.
I do notice the efficiency dropping quite a bit in the cooler weather. Like I am using 2% more power than previously which I was expecting. But I didn't expect the longer charge time in the winter.
Is the extra 1 hour or so to warm up the battery? And I'm assuming this is expected?

ETA: So after about 30 minutes or so (after the initial 4.5 hour estimate charge time) it has charged up 2% and now has switched back to a 2.5 hour charge estimate which is in line with what I have seen during warmer temperatures.

 

[DuncanM]

The ambient temperatures have dipped significantly lower the past few days. It normally took 2-3 hours to charge for my daily drive using 12A/240V (6-15). Just the past 2 days with the ambient temps in the 30F-40F range, I now have to charge it for 4.5 hours. I also hear a lot of different noises during the charging session, something like a compressor followed by a fan at times.
I do notice the efficiency dropping quite a bit in the cooler weather. Like I am using 2% more power than previously which I was expecting. But I didn't expect the longer charge time in the winter.
Is the extra 1 hour or so to warm up the battery? And I'm assuming this is expected?

ETA: So after about 30 minutes or so (after the initial 4.5 hour estimate charge time) it has charged up 2% and now has switched back to a 2.5 hour charge estimate which is in line with what I have seen during warmer temperatures.

I noticed my 2022 M3 RWD (LFP) was using a about 500w/hr when parked in ~25F temperatures, overnight. I presume the battery heaters are drawing that power to keep the battery from getting too cold.

 

[derotam]

The ambient temperatures have dipped significantly lower the past few days. It normally took 2-3 hours to charge for my daily drive using 12A/240V (6-15). Just the past 2 days with the ambient temps in the 30F-40F range, I now have to charge it for 4.5 hours. I also hear a lot of different noises during the charging session, something like a compressor followed by a fan at times.
I do notice the efficiency dropping quite a bit in the cooler weather. Like I am using 2% more power than previously which I was expecting. But I didn't expect the longer charge time in the winter.
Is the extra 1 hour or so to warm up the battery? And I'm assuming this is expected?

ETA: So after about 30 minutes or so (after the initial 4.5 hour estimate charge time) it has charged up 2% and now has switched back to a 2.5 hour charge estimate which is in line with what I have seen during warmer temperatures.

Cold temperature can definitely have an affect. You definitely need to do your charging immediately after driving or you can and will waste a lot of power to heating the battery unnecessarily.(I am assuming Tesla is still being dumb about this). Remember your 12A/240V is only ~3kW and for battery warming, per motor it can draw 3.5-4kW to heat the battery, so if you let your battery sit and cool down too much all available power will go ONLY to battery heating before it even thinks about starting to charge.

I would have hoped that Tesla would adjust this a bit. Forcing battery heating for a mildly cold battery when you are only able to charge at 3kW anyway is just a waste. If you took that same temperature battery to a supercharger you would get more than 3kW in charging capability immediately.

Charge as soon as you get home with a warm battery. You are in Michigan with only 3kW charging capability, you will lose if you schedule charge and let the battery cold soak before the scheduled charge time.

 

[metroplex]

I always plug in as soon as I get home. And I did notice that after about 30 minutes of charging (recovered 2%) the buzzing sound got quieter and my charge time estimate was more normal. But wow I didn't know it would require that much power to warm the battery. Kind of glad I went from 5-15 to 6-15. It would have taken forever with 5-15

 

[jjrandorin]

It would have taken forever with 5-15

People with 5-15 120v outlets in cold climates can easily end up in a situation where there is not enough power being delivered to warm the battery, so the car actually never charges, despite being plugged into an outlet overnight (or longer).

 

[ItsNotAboutTheMoney]

The ambient temperatures have dipped significantly lower the past few days. It normally took 2-3 hours to charge for my daily drive using 12A/240V (6-15). Just the past 2 days with the ambient temps in the 30F-40F range, I now have to charge it for 4.5 hours. I also hear a lot of different noises during the charging session, something like a compressor followed by a fan at times.
I do notice the efficiency dropping quite a bit in the cooler weather. Like I am using 2% more power than previously which I was expecting. But I didn't expect the longer charge time in the winter.
Is the extra 1 hour or so to warm up the battery? And I'm assuming this is expected?

ETA: So after about 30 minutes or so (after the initial 4.5 hour estimate charge time) it has charged up 2% and now has switched back to a 2.5 hour charge estimate which is in line with what I have seen during warmer temperatures.

How does your consumption compare between the warmer and colder weather?
You'll take a time hit from higher consumption as well as any extra battery conditioning.

 

[metroplex]

How does your consumption compare between the warmer and colder weather?
You'll take a time hit from higher consumption as well as any extra battery conditioning.

It's about an extra 2% consumption for my regular commute. Normally it will drop from 89% to 83% every day during warm weather. With temps in the 20s to 40s, it's now 89% down to 80% followed by the battery warming prior to charging. My garage isn't heated but it is attached and stays about 40F to 50F right now.

With the 2022.36 and 40 software, the Energy app shows me using thst extra 2% or so. I largely suspect it is from reduced brake regen.

 

[ItsNotAboutTheMoney]

It's about an extra 2% consumption for my regular commute. Normally it will drop from 89% to 83% every day during warm weather. With temps in the 20s to 40s, it's now 89% down to 80% followed by the battery warming prior to charging. My garage isn't heated but it is attached and stays about 40F to 50F right now.

With the 2022.36 and 40 software, the Energy app shows me using thst extra 2% or so. I largely suspect it is from reduced brake regen.

Well, 89% - 83% = 6%, 89% - 80% is 9%. Allowing for rounding, call it 1/3 to 1/2 extra consumption.
So that 2-3 hours could be 2 2/3 hours to 4 1/2 hours anyway just from the additional energy use, independent of conditioning.

 

[metroplex]

Well, 89% - 83% = 6%, 89% - 80% is 9%. Allowing for rounding, call it 1/3 to 1/2 extra consumption.
So that 2-3 hours could be 2 2/3 hours to 4 1/2 hours anyway just from the additional energy use, independent of conditioning.

Last night when it dropped to 80% with 30F weather, it said I needed 4.5 hours. After 30 minutes, it went up to 82% and then said I needed about 2.5 hours. Somehow it got 2 hours of charging done in 30 minutes, so the battery warming explanation is more plausible.

During warmer weather, I had to run errands one time and got it down to 80%. Took only about 3 hours total, maybe less because I have noticed it complete charging a tad sooner than originally estimated.

 

[derotam]

It's about an extra 2% consumption for my regular commute. Normally it will drop from 89% to 83% every day during warm weather. With temps in the 20s to 40s, it's now 89% down to 80% followed by the battery warming prior to charging. My garage isn't heated but it is attached and stays about 40F to 50F right now.

With the 2022.36 and 40 software, the Energy app shows me using thst extra 2% or so. I largely suspect it is from reduced brake regen.

Yeah that is a shorter commute. You may have issues even with the 6-15 when it gets really cold. If you find that the charge time starts getting to much longer(like all night) then you have run into the battery cooling more than what the charge input itself can compensate for. The good news is also that you have a short commute so you can always do a larger charge on the weekends to compensate for that.

 

[metroplex]

Yeah that is a shorter commute. You may have issues even with the 6-15 when it gets really cold. If you find that the charge time starts getting to much longer(like all night) then you have run into the battery cooling more than what the charge input itself can compensate for. The good news is also that you have a short commute so you can always do a larger charge on the weekends to compensate for that.

I average about 26-35 miles a day, which I believe is the average mileage for a typical driver in the US. But my plan wasn't to use the Tesla as a winter driver due to the road salt we use around here but it may dip into the lower teens this week so I'll get to see how that impacts my charging.

 

[Rocky_H]

Is the extra 1 hour or so to warm up the battery? And I'm assuming this is expected?

Yes and yes. It's having to divert energy into heating that is not going into charging, so the total charging time is going to be extended.

I would have hoped that Tesla would adjust this a bit. Forcing battery heating for a mildly cold battery when you are only able to charge at 3kW anyway is just a waste. If you took that same temperature battery to a supercharger you would get more than 3kW in charging capability immediately.

That's a bit interesting. I disagree that at a Supercharger it would just go ahead and slam 3 kW into the battery if the battery is too cold for that. It just won't let itself damage the battery like that. So on this home charging, it sees that it's too cold to take 3 kW and needs to warm some. Maybe it is only warm enough to take 1 or 1.5 kW. Since the source from the wall only has 3 kW available, should it split the power, sending 1.5 kW to warming and 1.5 kW to charging? Maybe. Or go ahead and send 3 kW into warming it a bit faster and then shift more into charging. Either seems practical.

But you might see a different behavior on a Supercharger because it has a much bigger power source. It could supply full power to the warming systems, like 6+ kW while also starting off 1.5 kW to charging the battery, or whatever the battery can take at that moment, and gradually increase charging power as it warms.

 

[derotam]

Yes and yes. It's having to divert energy into heating that is not going into charging, so the total charging time is going to be extended.

That's a bit interesting. I disagree that at a Supercharger it would just go ahead and slam 3 kW into the battery if the battery is too cold for that. It just won't let itself damage the battery like that. So on this home charging, it sees that it's too cold to take 3 kW and needs to warm some. Maybe it is only warm enough to take 1 or 1.5 kW. Since the source from the wall only has 3 kW available, should it split the power, sending 1.5 kW to warming and 1.5 kW to charging? Maybe. Or go ahead and send 3 kW into warming it a bit faster and then shift more into charging. Either seems practical.

But you might see a different behavior on a Supercharger because it has a much bigger power source. It could supply full power to the warming systems, like 6+ kW while also starting off 1.5 kW to charging the battery, or whatever the battery can take at that moment, and gradually increase charging power as it warms.

See now you are going to make me take data to categorize this stuff again. haha. Guess I gotta dig my SMT back out and plug it back in. Well actually I don't HAVE to go that far, I think the problem is acute enough that just using regen dots will be detailed enough...

Curse you Rocky! I thought I had got out of the data analysis and part of owning a Tesla!

 

[Rocky_H]

See now you are going to make me take data to categorize this stuff again. haha. Guess I gotta dig my SMT back out and plug it back in. Well actually I don't HAVE to go that far, I think the problem is acute enough that just using regen dots will be detailed enough...

Curse you Rocky! I thought I had got out of the data analysis and part of owning a Tesla!

That's what I do--cause obsessive people to go take data, while I don't care enough to do so myself. I'm a seat of the pants-er to the end. I just remember all these little details that other data collectors have reported over the years.

 

[jjrandorin]

I'm a seat of the pants-er to the end. I just remember all these little details that other data collectors have reported over the years.

+1

 

[derotam]

That's what I do--cause obsessive people to go take data, while I don't care enough to do so myself. I'm a seat of the pants-er to the end. I just remember all these little details that other data collectors have reported over the years.

So one drive this morning to work with SMT on and I have a few things to figure out again. As far as this topic is concerned, my initial very quick 30 sec test this morning showed no stator load while on 24A/240V with a battery temp of 10.6C. Obviously that is just one data point and it will be a better test when it gets colder.

Off subject slightly, all my previous data and graphs on the official Tesla forum about how preconditioning on the way to a supercharger seems to be completely junk now. Previously at over about 30mph there would be no stator heating power on a RWD. NOW there is additional stator heating over 60mph but SMT is not registering and additional power load to account for it. It's MAGIC evidently! Time to find/start a thread about that.

 

[Regaj]

Off subject slightly, all my previous data and graphs on the official Tesla forum about how preconditioning on the way to a supercharger seems to be completely junk now. Previously at over about 30mph there would be no stator heating power on a RWD. NOW there is additional stator heating over 60mph but SMT is not registering and additional power load to account for it. It's MAGIC evidently! Time to find/start a thread about that.

What you'll find is that the "preconditioning" alert while navigating to a SuperCharger is not a reliable indicator of whether the car is actually sending heat to the pack or not. Typically, once you get closer - in some cases, much closer - to the SC, it will begin to heat the cells.

Congrats on getting SMT. It gives you access to some fascinating data!

 

[derotam]

What you'll find is that the "preconditioning" alert while navigating to a SuperCharger is not a reliable indicator of whether the car is actually sending heat to the pack or not. Typically, once you get closer - in some cases, much closer - to the SC, it will begin to heat the cells.

Congrats on getting SMT. It gives you access to some fascinating data!

With respect, are you just making a random statement or do you have data to back up when(and how) it does and does not heat the cells? I ask because if you actually do have that data then perhaps you can contribute to my thread about the change in preconditioning operation HERE.

I have had SMT since 2018 when I got my Model 3 LR RWD and had been very active categorizing various behaviors while on the official Tesla forum.

 

[DrGriz]

40 degrees is cold? You guys don't know cold. 18 degrees:

 

[Regaj]

With respect, are you just making a random statement or do you have data to back up when(and how) it does and does not heat the cells? I ask because if you actually do have that data then perhaps you can contribute to my thread about the change in preconditioning operation HERE.

I have had SMT since 2018 when I got my Model 3 LR RWD and had been very active categorizing various behaviors while on the official Tesla forum.

Yes, my statement was based upon repeated observations of pack temps (albeit, during warmer weather). Frankly, I was quite surprised the first time I observed that behavior. Like most people, I assumed that if the car said it was pre-heating the battery while navigating towards a SuperCharger... the car was doing just that. However, sensor data showed that's not always the case. I've observed heat being sent to the pack (while navigating to a SC) well before the preheating battery alert displays on the screen; and I've observed no heat being sent to the pack even when the the screen has displayed the preheating message.

Of note, my readings are based upon actual real-time pack temps, and whether they change. Not stator temps.

I'll take a look at your other thread.