Cold Climate with short Commute

[mswlogo]

My commute is like 5 miles in 10 minutes one way. When it’s really cold out I’m concerned things won’t be warmed up enough for the charge to start when I get home.

I’ve been following the recommendation to plug in nightly.

But I’m concerned that I will spend more electricity heating the battery up for a small charge daily.

Will things be warmed up in 5 miles when it’s bitter cold out? No highway.

Should I skip charging nightly during cold spells?

 

[diamond.g]

My commute is like 5 miles in 10 minutes one way. When it’s really cold out I’m concerned things won’t be warmed up enough for the charge to start when I get home.

I’ve been following the recommendation to plug in nightly.

But I’m concerned that I will spend more electricity heating the battery up for a small charge daily.

Will things be warmed up in 5 miles when it’s bitter cold out? No highway.

Should I skip charging nightly during cold spells?

Do you preheat before leaving?

 

[mswlogo]

Do you preheat before leaving?

I have not decided on that yet. My guess is no. Depends on the “cost” of doing so.

I suspect if I did it would not be enough to give enough time to charge and heat.

I have a fairly low amp charging circuit (30A).

Does the pre heat use auxiliary heat or part of the battery/motor heat regulation loop?

It seems to instant to be part of the battery/ drive loop. So I would assume if I preheated I’d only run it for 15 min or so ahead of leaving.

And the battery would be extremely cold overnight.

 

[diamond.g]

I have not decided on that yet. My guess is no. Depends on the “cost” of doing so.

I suspect if I did it would not be enough to give enough time to charge and heat.

I have a fairly low amp charging circuit (30A).

Does the pre heat use auxiliary heat or part of the battery/motor heat regulation loop?

It seems to instant to be part of the battery/ drive loop. So I would assume if I preheated I’d only run it for 15 min or so ahead of leaving.

And the battery would be extremely cold overnight.

Preheating would use shore power extending your range (only for one leg of your commute). I think if it is cold enough, when you preheat, it should try to bring the battery temp up as well. On the return trip the vehicle will use more energy to warm the battery up if needed. Not sure how much yet as it hasn’t been that cold where I live yet.

 

[Kermee]

My commute is like 5 miles in 10 minutes one way. When it’s really cold out I’m concerned things won’t be warmed up enough for the charge to start when I get home.

I’ve been following the recommendation to plug in nightly.

But I’m concerned that I will spend more electricity heating the battery up for a small charge daily.

Will things be warmed up in 5 miles when it’s bitter cold out? No highway.

Should I skip charging nightly during cold spells?

10 miles is about 2.5kWh to 3kWh of power so yes, pre-heating the battery before charging could easily be more than the actual kWh you need to charge.

TBH, this is almost a wait-and-see at this point for you. There's definitely charging inefficiencies when the battery pack is cold if some power is being used to warm the battery. If I were you, I would probably charge up to 80-90% and drive it until it's down to around 20-30% before recharging. 7.2kW is still a decent charge rate. Maybe charge only during the weekends? You're literally only driving about 50 miles a week so that's barely a sixth, or fifth in worst case scenario, of your vehicle's range.

 

[mspohr]

My commute is like 5 miles in 10 minutes one way. When it’s really cold out I’m concerned things won’t be warmed up enough for the charge to start when I get home.

I’ve been following the recommendation to plug in nightly.

But I’m concerned that I will spend more electricity heating the battery up for a small charge daily.

Will things be warmed up in 5 miles when it’s bitter cold out? No highway.

Should I skip charging nightly during cold spells?

You could probably just charge once a week and it would be more efficient.

 

[gavine]

You could probably just charge once a week and it would be more efficient.

If you do charge once per week, I would schedule the charging to end close to the time you will be leaving on Monday morning. Charging warms the battery and will enable regen for that one trip. Better than nothing.

 

[ewoodrick]

Have you heated your other vehicles? If not, then you probably have nothing to worry about.

For batteries to be too cold, it has tobe really cold

 

[mswlogo]

Well it’s only been like 40F at night lately and the “limited regen” warning was on half way to work. And it’s in an attached garage. Doesn’t seem to be a pattern. Days I thought were colder the regen warning was gone by the time I got to the end of the driveway. I wish they would display component temps somewhere.

We might get a spell of like 3 weeks at or below 0F over night.

I’ve already put over 1,000 miles in just 3 weeks. And some work days I’ll run errands etc. I do most driving on weekends. Often 300 miles to a cabin and back.

Timing preheat in the morning I think will be the most wasteful.

Possibly when it’s really cold I’ll be running heat full blast and that combined with the 5 mile drive will be enough to prep battery for a charge. And I won’t feel guilty doing a 5 minute pre-heat to take the edge off before heading home.

After the car has “warmed up” does it use heat from battery and motors to heat the cabin?

 

[juliusa]

My guess is your battery heater will be on both ways during your commute, and also when you are charging. Expect to use double the energy in the winter compared to summer.

If you really want to minimize kWh, perhaps charge only when the car is below 30%, and schedule charging to complete before you leave. Personally, I would just plug in every night and preheat the cabin before leaving home and before leaving work.

Just think about how much electricity (and time) you are saving compared to having a 50 mile commute.

 

[SSedan]

I think the only way this saves meaningful energy is if you turn on max range so it turns off battery heating.

 

[Stretch2727]

The battery will not be warm in 5 miles with out a preheat. It may not even get there with a short pre-heat. There is no direct battery heater in the Model 3 only indirect through the motor and inverters. It will run electric current through the motor without moving the car to try to heat the battery and motor in pre-heat mode.

I have a similar commute. 6 miles each way. I plan to preheat the cabin. Enjoy having regen braking and a warm car to get into. Pre-warming the car is one nice advantage of an electric car and have done for years with other electric cars. Enjoy it and don't worry too much about the cost. The energy you use (and cost) is way lower than an ICE.

 

[SSedan]

Cabin heat and lack of Regen are going to jack energy use even if you stop battery warming ecxept to charge.

 

[mswlogo]

I don’t mind spending some energy on preheat. I just don’t want to defeat the purpose of having an EV car. I’m already at the top of the electricity cost curve of $0.23 per kWh.

I don’t mind spending energy on staying warm in the car as well

So how cold does it need to get say before my 5 mile commute wouldn’t bring battery up to temp? Ready to charge?

Will charging sustain the heat or will it continue to heat while charging.

Will the car switch over to motor to heat cabin after a while (on a long trip)?

 

[tomas]

TBH, I don’t think anyone on this forum can answer because it is highly dependent on how cold, particulars of your commute, your driving style, and the shelter your car “lives” in.

I suggest you get a notebook and try different approaches taking copious notes on usage until you find out what works in your scenario.

At .23 per kWh I doubt you’ll “waste” more than $20 before you find your optimal solution.

 

[mspohr]

I've had my Model S for four years. When I first got it I, too, was obsessed with "efficiency". I would worry about optimizing charging, running the heat and AC, etc.
However, more recently, I've become more relaxed. I've realized that I am running an incredibly efficient car and it's just not worth the time to worry about "efficiency". I just drive the car and charge it when it's convenient and turn on the heat and AC whenever I want. These things actually make very little difference in efficiency. I've come to the point where I enjoy the car every minute I drive it and I don't worry about any of these things.
So, my advice to you is to just do what you find most convenient, sit back and relax and enjoy the car. Don't worry, be happy. The car will take care of itself. You will enjoy driving the absolute best car available today and the most efficient (regardless of how you operate it).
You have arrived at the future. The future is starting... now.
Enjoy!

 

[mswlogo]

I think the priority of getting my garage insulated has certainly gone up. It really didn’t matter much before with the excess heat of an ICE vehicle.

 

[mswlogo]

I've had my Model S for four years. When I first got it I, too, was obsessed with "efficiency". I would worry about optimizing charging, running the heat and AC, etc.
However, more recently, I've become more relaxed. I've realized that I am running an incredibly efficient car and it's just not worth the time to worry about "efficiency". I just drive the car and charge it when it's convenient and turn on the heat and AC whenever I want. These things actually make very little difference in efficiency. I've come to the point where I enjoy the car every minute I drive it and I don't worry about any of these things.
So, my advice to you is to just do what you find most convenient, sit back and relax and enjoy the car. Don't worry, be happy. The car will take care of itself. You will enjoy driving the absolute best car available today and the most efficient (regardless of how you operate it).
You have arrived at the future. The future is starting... now.
Enjoy!

If I had a longer commute I think I wouldn’t care that much. But I think I have an usually short commute. And that can be hard even on an ICE vehicle as well.

I could go no charge all week and wait until I travel to the cabin where I will always stop at a supercharger. But I wasn’t sure if that would be hard on the battery. By not doing the recommended plug in every night.

I’m also curious at temperature points this could matter. If it’s only when say it’s below 10F I’ll either skip charging nightly or eat the execessive reheating to charge a small amount of usage daily. Long spells below 10F are not to common. So either way would be fine. But months below 32F are common.

Is there a way to tell if it’s doing more heating than charging. Low mile per hour charge rate?

 

[TLej]

Temps regularly drop below -30 C where I live. I know the 3 and the S work differently in how they heat the pack, but don’t worry about the charging. I have charged overnight off a 110 outlet in -40 temps with the car sitting outside exposed to the elements. Even when it’s -20 or -30 outside, my attached garage (which is insulated but not heated) stays above freezing. Sure, regen will be limited, but that’s just life in winter. Don’t worry about changing your charging schedule, but expect to use quite a lot more energy when it’s cold. For what it’s worth, I have a similar commute (13 km, like 8 miles?) and the car is heating the battery most of the way on the commute in winter. I charge when I get down to about 30%, and I only charge to 80% typically. In summer that usually means I charge about once/week. In winter, it’ll be every couple of days. I charge at 40A on an HPWC and there is never an issue charging the car overnight.

Don’t sweat city driving when you have a place to come home and charge every night. Seat heaters, cabin heat, use as much as you want. A road trip where the distance between chargers is near range limit is a different story, then you might have to manage cabin heating against range needs, but it’s simply not an issue in city driving in my experience.

 

[diamond.g]

So my commute is ~37 miles 1 way. This morning it was ~40F outside, even with preheating the cabin for 25 minutes I had limited regen for almost all of my trip. While preheating the car I saw it pull about 24 amps from shore power to get the cabin to 74F. I have Remote S and when I get in the car this afternoon I'll see if the API output of the battery section will show if the battery is in heat mode. I forgot to do that this morning.

I concur with what everyone else is saying, you have such a short commute, just drive as normal and plug in whenever convenient. Such a short ride there is no way the battery will be warmed up enough to not limit regen while driving.