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Cold Climate with short Commute
- Thread starter mswlogo
- Start date
mspohr
Well-Known Member
You're not going to damage the battery as long as you keep it between 20% and 80%.
There are a few software applications which can monitor the energy use of the car. If you want, you can use these to see how much energy you are using for heat, charging, driving, etc. (Not sure if these work with Model 3)
Stretch2727
Engineer and Car Nut
I think you are thinking about this too much. A short commute will have no impact other than you will not have full region and full power. And you will use more energy in the winter with or without pre-heat.
Are you concerned about the impact on the battery or the amount of energy used?
The battery will last longer stored at cooler temps. You car is going to be sitting most of the time so your climate is good for the battery.
The cold does impose some operating limits on the battery. The Tesla BMS will take care of these limits. The main downside is lack of regen. Preheating the cabin and battery will avoid some of this but not all.
Here is a link with a table for general degradation of LI versus temp. (Not specific to Tesla but shows the trend.) Again, with cold there is less battery degradation but it does impose some operating limits on the battery.
https://batteryuniversity.com/index.php/learn/article/how_to_prolong_lithium_based_batteries
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I'm worried if I follow the manual (to keep your Tesla Plugged in when not in use) it will cost me a small fortune because I'll be heating way more than charging. I think I do need to think about it and do what some folks recommended and ignore the recommendation and accrue more usage before plugging in when it's cold out.
I also don't have experience of knowing what those thresholds are to stop plugging in nightly. Below 50F, Below 32F, Below 0F?
It was 28F last night. Garage was probably low 40's. It did not put up the "No Regen Warning" but I believe it was in partial regeneration.
And never made it to full regeneration. I still plugged in and it was at full charge rate (miles per hour) after about 5 minutes.
I still got close to 260 wh/mi (with heat going). So it's still doing pretty good.
I have a similar commute distance and also charge in an attached garage. I charge with regular 110 V plug. Once I came home after the car was out all night with temps near freezing. When I first plugged in it said it would take 12 hours to add 30 mi of charge, but after things warmed up in the garage, charge time dropped and it charged in about 6 hours. I have no idea how much energy went to heating vs charging. At 7-8 cents per KWh I preheat the cabin anytime its cold and leave it plugged in whenever it's in the garage. I just enjoy the comfort of a warm car.
Kermee
It's Not Easy Being Green
Consensus is even when plugged into "shore" power (and not charging), the TM3 will not actively heat the battery unless:
#1. Temperature of the pack reaches below -30C (-22F) for an extended period of time, which it would use "shore" power to run the motor to generate heat to warm the pack to prevent permanent damage.
#2. You manually turn on "Climate Control" with the heat turned up when the battery is in a
"Snowflake" condition. (Page 44 of the TM3 Manual).Otherwise, it shouldn't draw any more power than usual.
Stretch2727
Engineer and Car Nut
Like others have said it will not draw from shore power when plugged in unless you preheat or it is extremely cold. -30C.
One way to minimize the total energy used and to have some regen is to have it charging as you leave for your drive in the morning. Set the timer so it will still be charging as you leave. What you loose in heating the battery for charging you will make up during your drive.
I actually do both preheat and have it charging close to when I leave. I like the having regen and like having the cabin warm
. The recommendation to plug in the car is just a blanket safety measure to be sure power is there in case there is a very low state of charge or it is extremely cold. Generally it is not needed unless you want to charge the car.
I have had electric cars for more than 5 years and yes you will use 20-30% more energy overall in the winter. Again, it is still much less total energy and cost than an ICE car so I would not worry too much.
Setting it to charge before I leave I think would use more total energy (more waste) than anything. The car will naturally be warmest when I get home in the evening. The days are warmer and it has been driven (albeit often short drive) with heater commonly on.
Waiting for that little bit of heat to cool off, and often a huge drop in temps overnight. I’ll spend way more on heating than charging.
Waiting for that little bit of heat to cool off, and often a huge drop in temps overnight. I’ll spend way more on heating than charging.
diamond.g
Active Member
gavine
Petrol Head turned EV Enthusiast
Does the car warm the battery just to charge on a 40A home charger? I thought it only warmed it for supercharging. I'm probably wrong, but surprised if it does warm it for slower charging like that.
Stretch2727
Engineer and Car Nut
I think you are confusing the limited charging power with additional power that is being used. The car has complete control over how much power is being delivered at a given moment from your charger.
The charging is just limited until the battery is warm. You can only push so much current into the battery due to a higher internal resistance when it is cold. Just like regen is limited with a cold battery. Most of the warming is self heating from the internal resistance of the battery as is charged. The model 3 does not have a separate heater to heat the battery so there is no other place for the power to go other than into the battery. It is possible the some current is cycling through the feature the motor has to heat the battery but this is likely minimal and may not even be active during charging. Hope this explains it better.
Anyway, my charger measures the amount of energy the going into the car. When the battery is cold (below 32F) sometime I will measure the difference between the energy charger delivers and the energy delivered to the battery in the car. I am pretty sure the difference will be minimal even with a cold battery. Give me a few weeks until we have a good cold spell and I will give it a try.
Yes, it definitely does, depending on temperature level. When the cells are really cold, it would be actually damaging to charge them at all, so it must warm them up at least some, before it can do any charging, and then it gradually increases the amount of current you can give them as the temperatures keep rising.
Update: Someone had suggested to try lowering the current to see if you could avoid heating battery if I didn't mind it taking longer. This sounded like a great idea. But it didn't work. Quite often on my 30A Circuit I'll see it pulling 24A but only getting 11 mi/hr (and I turned heat OFF to be sure it was not cabin heat). So I though this was a good chance to try that experiment. I turned the Amp limit down to 15A which should do 11 mi/hr. And it dropped to like 4 mi/hr. It's really odd it did this because it was warm enough to fo 11 mi/hr at higher amps why couldn't it continue at 15A (240V).
Also I have fully insulated my garage and sheet rocked and taped it. So it tends to be a good 15-20F warmer than outdoors. This helps a huge amount. Sometimes I charge at midnight after it's been at work all day and home on a short commute and many days it will ramp right up to 21 mi/hr (at my max of 24A/240V).
Also I have fully insulated my garage and sheet rocked and taped it. So it tends to be a good 15-20F warmer than outdoors. This helps a huge amount. Sometimes I charge at midnight after it's been at work all day and home on a short commute and many days it will ramp right up to 21 mi/hr (at my max of 24A/240V).
I think that we should all worry a bit less about this stuff. The only time you should give this any thought is if you part outside in -30C for days or something like that. I live in Utah, park in an insulated garage that stays at 5C when it is -15C outside and I charge, preheat, and drive without giving it all much thought whatsoever. Even if I parked outside in -15C I would do the same. If the charge is low when I get home I plug it in. Otherwise I just leave it. Even if regen is limited I still have brakes I can use to stop the car.
We all paid over 50k for our cars, extra few dollars for electricity here and there should not matter to any of us.
We all paid over 50k for our cars, extra few dollars for electricity here and there should not matter to any of us.
That's definitely not the reason people freak out over it. It's just the thinking of: "Here's how it's supposed to act, and it's not doing that. Something's wrong!"
I think if I was paying $0.07 kwh I wouldn't care. But at $0.23 kwh an hour I have to pay attention.
I'm starting to approach the cost of running ICE in $$/mi, I expected 1/4 the cost in fuel goin into this.
I'm closer to 1/2 (or worse) in cold weather.
Because I have a very short commute in cold weather it's really worst case, I could spend as much fuel heating the battery as I am charging it if I don't think about it. If it's something simple I can do, like just lower the current, I'd do it.
I also don't like wasting energy if it can be avoided (they do use fossil fuel to make electricity as well as nuclear).
Regen is the least of my worries.
Olds442
Member
It will still cost half of an ice car in consumption. Leave it plugged in. Charge to 80-90%.
Also, preheat the car for a half hour before leaving. Enjoy.
Also, preheat the car for a half hour before leaving. Enjoy.
That’s the most wasteful thing you can do.
I can actually drive the car without regen. Apparently that is rare talent around here. As well as looking at actual cost to operate the car.
gavine
Petrol Head turned EV Enthusiast
I hate when there's no regen. I still think people are discounting the amount of energy regen offers. It's not a negligible amount. Brakes waste an enormous amount of energy.
