Slow (17kW) Supercharging in the cold. You?

[bpjod]

I want to know if what I'm experiencing is normal for the Model 3 or if I have an issue with my car. 10 days ago I went into the city to run some errands. It was -28C/-18F. I didn't think I needed a charge to get home, but given how cold it was I figured I'd play it safe and grab some electrons at a Supercharger and stroll around the mall for a bit. Not that it was a worry for me that day, but I noticed that whenever I checked my app, my charging rate was only 17 kW even though I stayed there for around 45 minutes.

Tomorrow our family is heading on a trip to a ski hill about 1,000 km away, with a roof box on. I want to be sure we're not going to be stuck with such slow Supercharging. As a test, last night after work I drove to our nearest Supercharger. The trip was mostly highway, stats for the drive were: 65.3 km/40.6 mi, 52 min, 248 Wh/km and -20C/-4F. I pulled in with 48% on the battery and a blue snowflake still - the regen line was about 1/2 dotted and 1/2 solid. There was only one other car charging there and they left after about 15 mins, I was not on a paired charger with them (4A them, 1B me).

I plugged in and got an 18 kW charge rate. After 12 minutes the blue snowflake/bar went away and I was still at 18 kW. After 30 minutes I was still at 18 kW and called Tesla support to discuss this with them. They appreciated my concern over the slow charge rate. They suggested preheating the battery (I hadn't, it was parked outside at work all day), but were a little surprised that it was still cold after a 65 km drive (windchill at -20C and 120 km/h, maybe?) and 30 minutes charging. They ran diagnostics on my car and said everything looked okay but maybe I could bring it into a service centre for a more thorough check. This is not happening unless I can confirm that there's something wrong; without more data I suspect it's simply how the car works in the cold. After about a 15 minute call with them my car was now charging at 19 kW and I'd been there for about 45 minutes. I disconnected and drove home.

So now I want more data from other cars. Is my car reacting normally? I'm fine with the loss of range from a cold battery, this I expected. However I did not plan for an 80% reduction in charging speed in the winter. My trip to the ski hill is through some pretty unpopulated areas of the Rockies in the middle of winter with a roof box and keeping my family safe is a priority.

If I'm stuck charging at 20 kW, this is going to be a much slower trip than I have been anticipating. I expect using 250 - 300 kW for the trip. If we leave home with a full battery and arrive at our destination with 25% charge, that leaves about 150-200 kW charging requirements. At 100 kW I'm looking at 1.5h to 2h charging. A couple of nice meals and everyone's happy. At 20 kW that changes to 7.5h to 10h charging; the trip is now twice as long as if I take my ICE SUV. You can see my dilemma.

Now that we've had some cold spells in the Northern US and Canada, I'm looking for others' experiences:

• At these temperatures, if I had been driving longer, would my battery have warmed up more?
• How long does it take a cold battery to warm up at a Supercharger in these temps?
• Is that the best I can expect at -20C/-4F regardless of warm/cold battery?
• If I depart with a preheated battery will it stay warm the whole trip and give me fast charging? I'll be able to do this as I'll preheat before leaving home and we're staying at a rental property with an EV charger.
• Am I the only one with experiences like this?

I need to know by tomorrow afternoon as I need to decide by then whether we're taking the Model 3 or our ICE SUV with the uncomfortable seats and the dreadful (premium!?) sound system. TIA!

 

[Kirby64]

Some folks have reported it takes ~2 hours of highway driving to have full supercharging speeds upon approval in ~32F weather. It wouldn't surprise me at all that you would only get 18kW after a cold soaked battery is only driven at an average speed of ~45mph for 50 minutes in -4F weather.

Assuming you're charging at home, just schedule your charging to finish right before you leave and you should be fine for supercharging by the time you hit the first supercharger. If for some reason that doesn't work, Bjorn is a big proponent of doing long full tilt bursts of acceleration, followed by aggressive regen. That'll heat up the whole system as quickly as possible. You may actually find it's faster to burn off some battery capacity doing that and the increase in supercharger speeds will make up for it.

 

[Big Earl]

The first leg of the trip is the most important for getting the battery up to temperature, as it can take up to 2 hours of highway driving to fully warm the pack.

Some quick cold weather travel tips:

1. Charge to 90% the night before your trip
2. Two hours before departure, raise your charge limit to 100%. This will heat the pack up and begin charging it.
3. Plan to arrive at your first Supercharger at around 25% state of charge (safe margin of error), then speed up as you get half way to the first charging stop. Arriving between 12 and 15% is ideal.
4. Plan a similar arrival strategy for subsequent charging stops.
5. If you don't have 240 volt charging available at your destination, be sure to charge at a Supercharger to at least 70% before you park the car for the night. Do not wait until morning to charge or you will run into slow charging again due to cold battery temperatures.

 

[bpjod]

The first leg of the trip is the most important for getting the battery up to temperature, as it can take up to 2 hours of highway driving to fully warm the pack.

Some quick cold weather travel tips:

1. Charge to 90% the night before your trip
2. Two hours before departure, raise your charge limit to 100%. This will heat the pack up and begin charging it.
3. Plan to arrive at your first Supercharger at around 25% state of charge (safe margin of error), then speed up as you get half way to the first charging stop. Arriving between 12 and 15% is ideal.
4. Plan a similar arrival strategy for subsequent charging stops.
5. If you don't have 240 volt charging available at your destination, be sure to charge at a Supercharger to at least 70% before you park the car for the night. Do not wait until morning to charge or you will run into slow charging again due to cold battery temperatures.

Thanks @Big Earl, that is more or less how I planned on doing the trip. I didn't realize I'd need 2h to prewarm (I'd planned for 1h) the battery or to warm it while driving. As long as it will get fully warm and charge at >60 kW I'll be happy. I will pre-heat and the first Supercharger I plan on stopping at is 2h15m away. I guess at that point I'll quickly find out how the Supercharging for the rest of the trip will be!

I've done a few trips to a closer (370 km/230 mi away) ski hill with the roof box on, but those trips have been with only one Supercharger stop and a long supper (car was fully charged before we'd paid the bill) and the temps were around freezing, not as cold as the trip we're about to embark on. The first of those, the range hit from the roof box was my chief point of anxiety, but not as bad as I'd feared. Now my worry is slow Supercharging.

If I get some votes of confidence that I should be able to charge reasonably quickly with appropriate pre-warming and a couple hours drive to the first Supercharger then I'll give it a go. I still fear that the cold temps and windchill effect will cool the battery and I'll arrive and be stuck charging slowly. More input for whether or not this is an issue is still appreciated.

Just in case, I just dug out the SUV, pulled it into the garage and turned on the garage heater. Then I trudged through some mid-thigh drifts to go to the shed to get the box of Yakima rack hardware for the SUV so I can mount the roof rack on the SUV this evening in case I need to drive that tomorrow...

 

[bpjod]

One more quick question. In order to pre-heat the battery all I need to do is bump the max charge from 90% to 100%, correct? Or do I have to also turn on cabin heating? My plan is to bump up the max charge about 2h prior to departure, but to only turn on cabin heating about 10-15 minutes prior to departure. That will work for pre-heating the battery, right?

 

[Big Earl]

In order to charge, the system will heat the battery up to somewhere between 0 and 10 degrees Celsius; the exact number is elusive and depends on a number of conditions like current state of charge. So initiating a charge will effectively preheat the battery, which will give you a head start on your trip. The heating process takes time, as the battery's mass is quite large (1,000 lbs), which is why I recommend initiating a charge about 2 hours before departure.

Cabin heating will warm the cabin up and heat the battery, but to a lower level than charging. At least that seems to be the case in my experience.

 

[CCIE]

If you have the snowflake or any regen dots then supercharging will be very slow because the battery is cold. Even after the regen dots disappear the battery can still be cold enough to reduce supercharger speeds.

Best thing to do is make sure your charging at home completes right before you leave, and then driving for 200 miles should get/keep the battery warm. This is also why you always supercharge when you get to your destination, not the next morning when the battery is cold.

 

[Nocturnal]

I've not noticed any real difference in charging while it's very cold out. I guess if you parked overnight and then tried to charge, but if you are using a supercharger then that means you have already been driving for some time. (generally)

 

[Falkirk]

I parked in an open garage while at a hotel during a cold spell (-15c) for 2 days. I drove about 45mins to a supercharger and just lost the snowflake on the battery but only charged at maybe 17kW as well. I remember asking the Model S owner if the charge was good for him because I wasn't expecting it to be so low but it's my first winter and I'm learning!

Even at home I remember always getting 70km/h charge but I've seen many times high 50's or 62 recently because of cold-related effects it seems.

 

[Rocky_H]

This is probably going to be an unpleasant surprise for a lot more people. The methods they use for heating the Model 3 battery for charging speeds do not seem to be nearly as effective as the S and X.

 

[bpjod]

OP here. On the road trip. Decided to go with the Tesla. I charged the car for 3 hours to 97% prior to leaving. Drove 98 km to our first Supercharger. No blue snowflake and no dots on the regen bar. Temps on the drive ranged from -22C to -18C. We pulled in with 58% left on the battery and used 287 Wh/km. It's -18C here at the Supercharger. We're charging at 24kW.

Tonight we spend the night at a hotel with a Supercharger and tomorrow is forecast to be much warmer. Here's hoping for faster charging on the rest of the trip!

 

[ItsNotAboutTheMoney]

This is probably going to be an unpleasant surprise for a lot more people. The methods they use for heating the Model 3 battery for charging speeds do not seem to be nearly as effective as the S and X.

The S and X have dedicated battery heaters, which means that it doesn't take as much driving to heat the battery.

 

[bpjod]

I'm beginning to think a cold weather package with a battery heater, heated steering wheel, heating of the door handles, charge port cover, AP cameras and around the window seals on the doors as well as possibly some insulation under the battery might be in order.

 

[NHLakes]

I'll second what @Kerby64 said above:

On my Model S, I too have found that doing long full tilt bursts of acceleration, followed by aggressive regen (to the current cold-battery regen levels). Starting that cycle about 10 miles before reaching the supercharger seems to do the trick.

It sure would be nice if the cars would utilize the superchargers to bring the batteries up to temperature for most efficient charging.

 

[CCIE]

OP here. On the road trip. Decided to go with the Tesla. I charged the car for 3 hours to 97% prior to leaving. Drove 98 km to our first Supercharger. No blue snowflake and no dots on the regen bar. Temps on the drive ranged from -22C to -18C. We pulled in with 58% left on the battery and used 287 Wh/km. It's -18C here at the Supercharger. We're charging at 24kW.

Tonight we spend the night at a hotel with a Supercharger and tomorrow is forecast to be much warmer. Here's hoping for faster charging on the rest of the trip!

You used 39% of the battery to go 98km? That’s rough.

At those very cold temperatures I’m not sure that anything you can do will get the battery warm enough for reasonable supercharge speeds. Keep us posted on how it goes.

 

[bpjod]

This leg, from Red Deer to Calgary: 126 km and 308 Wh/km. At least when I pulled in to add some charge I started drawing 84 kWh. That's more like it! Temps -21C to -23C.

Keep in mind I'm using a roof box, for people in the car and every cubic cm is full of gear.

 

[Big Earl]

This is probably going to be an unpleasant surprise for a lot more people. The methods they use for heating the Model 3 battery for charging speeds do not seem to be nearly as effective as the S and X.

I don't think the method of heating is the problem. The setpoints just aren't as aggressive. I think Tesla is still trying to strike a good balance between providing good charging speeds while not wasting a lot of energy heating the battery unnecessarily.

 

[CCIE]

I don't think the method of heating is the problem. The setpoints just aren't as aggressive. I think Tesla is still trying to strike a good balance between providing good charging speeds while not wasting a lot of energy heating the battery unnecessarily.

The car needs a mode that lets it draw some of that supercharger energy that can't used to charge the cold battery and use it to heat the battery as quickly as possible. That assume the motor waste heat system is actually capable of generating enough heat while sitting at a supercharger to warm up the battery in a reasonable amount of time.

 

[Big Earl]

The car needs a mode that lets it draw some of that supercharger energy that can't used to charge the cold battery and use it to heat the battery as quickly as possible. That assume the motor waste heat system is actually capable of generating enough heat while sitting at a supercharger to warm up the battery in a reasonable amount of time.

It does heat the pack while supercharging... it just takes a lot of time to warm it up. Tesla could improve this by giving us a manual pack heating option that could be activated well in advance of arriving at a supercharger.

 

[Rocky_H]

I don't think the method of heating is the problem. The setpoints just aren't as aggressive.

No & Yes. Sure, they could use better set points or control, but I disagree wholeheartedly in your statement that you don't think the heating method is also a big problem. It really is less effective at generating much heat quickly.

It does heat the pack while supercharging... it just takes a lot of time to warm it up.

So there you go--the method of heating is the problem. S and X are much quicker at that.

I think Tesla is still trying to strike a good balance between providing good charging speeds while not wasting a lot of energy heating the battery unnecessarily.

Heh, you left out the main factor of what they were trying to strike a balance between. They were trying to go cheaper. I'm sure they knew that the Model 3 heating methods were going to be less effective, but probably thought it was good enough. And sometimes for some people in some temperatures, it is, but in other cold places, it isn't.

The car needs a mode that lets it draw some of that supercharger energy that can't used to charge the cold battery and use it to heat the battery as quickly as possible. That assume the motor waste heat system is actually capable of generating enough heat while sitting at a supercharger to warm up the battery in a reasonable amount of time.

I'm pretty certain it is already doing that. While it's sitting on a Supercharger and has access to virtually unlimited power levels, that would be the time when it would be using that power to run that motor-heating-the-battery method. The fact that it takes so long for charging speeds to climb upward seems like the most clear evidence that it just doesn't generate heat as fast as the S/X battery heater.

Tesla could improve this by giving us a manual pack heating option that could be activated well in advance of arriving at a supercharger.

This is something I'm still skeptical of about this method of heating with the motor. I don't know if it can do that. The method of heating using the motor needs to run current through the motor windings, and obviously it can do this when the car is parked. Keeping the motor locked and not moving can be providing extra resistance to the current in those wires because of the magnetic fields, so generating extra heat. But when the car is driving and needs to use those windings in it's particular directions and frequencies to rotate it at the speeds the driver is controlling, I am not sure it can also use those wires at the same time for generating extra heat.

So this is where I see one of the possible downsides to this Model 3 method. I'm not sure it can create any extra heat beyond the waste from operation while the car is driving. But certainly it can do it while parked, and there definitely should be a software control made available that could let owners turn it on.