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High cost of charging according to TeslaFi?
- Thread starter myisking
- Start date
Over the last 2800 miles, my driving energy consumption rate is at 309 Wh/mile... thanks to my lead foot.
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rejedejo
Member
This is the opposite for me. For the Tesla I have sentry mode disabled because it is parked in my garage and I also rarely bother preconditioning it because again it's in my garage. Who preconditions for 4 hours?
The ICE car is in a parking lot. It does have a camera! I have a dash cam in front and back recording in parking mode. The car also has a two way drone mobile remote start and gps. It literally does what the Tesla app does. Dog mode I don't have a dog so doesn't matter to me. Camp mode I've never turned on either.
Baseline I use the Tesla exactly like any other car and it uses energy parked on its own in winter without me even touching it. Totally energy consumption per mile I will figure out next week. I am going to track what I put in through my chargepoint charger at the end of the week. I started today from 90%
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Pluturi
Member
OP - Not sure that you got an answer to your question as the thread went a little off topic...
I have an S, so the absolute values are higher in any case. I also have a HPWC and Supercharged a lot in this time frame as explained below which has some beneficial effect on the overall efficiency, but I'll skip that for now.
If I look at my TeslaFi data over the same time frame I get much better efficiency out of total kWh added (92% of my kWh added is used in drives). Some of this is due to the fact that I have a cross-country round trip so a lot more miles being driven relative to time sitting around not driving. Your average drive distance is pretty short, so this means that you are using quite a bit of power in sentry mode, car preconditioning, etc. relative to the amount you are driving. As the temperature drops, this will be an even larger factor. I think if you look at this data in the fall separate from the winter you will see a significant difference. My fall efficiency is 94% while my winter efficiency is 81%.
In any case, I don't think you're math is wrong, and there are some things you can do that others have already suggested to reduce your idle consumption at the expense of some conveniences.
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Well that took awhile... I’m charging two EV’s from this charger, so I had to distinguish between the two using the graphs to make sure I was looking at the MY, using the higher charge rate as a way of verifying, for the last four months. One thing to note is that my Dad has an MX 100d and occasionally uses my charger (probably around 3-4 times since I bought our MY) so this result will include that as well as there’s no way to distinguish which Tesla it is using the juicebox app.
Having said that, the total input kWh I logged on the charger since the date of MY delivery is 1198 kWh. The MY reports 865 kWh consumed. So there’s about 38% more energy to add on top of what the car records, if we assume that little energy was consumed by the MX. If we instead assume that the MX used a total of 100 kWh, then that brings the extra energy usage down to about 27% by my math.
I think a fair guesstimate to the additional energy used when parked would be around 30%, which doesn’t surprise me at all as I can appreciate the amount of energy that is inevitably required to do the things that I ask it to do, all of which are not required in order to drive the car.
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Real world numbers. I've driven 46.5 miles since charging to 90% on Sunday. I am now at 55% lol. Temperatures have been in the 20 - 36 range.
I have no monitoring apps. Did not even touch the car or app yesterday and I am an average driver. I don't accelerate fast or anything. Cabin temp I keep at 68 auto. No sentry mode.
I'd say the driving was 50% highway.
I won't charge till Saturday so we can get real numbers.
I have no monitoring apps. Did not even touch the car or app yesterday and I am an average driver. I don't accelerate fast or anything. Cabin temp I keep at 68 auto. No sentry mode.
I'd say the driving was 50% highway.
I won't charge till Saturday so we can get real numbers.
Charging on 120v or 240v? Preconditioning before departure? Using utility power?
On my i3, I see about a 20-30% reduction in range during the winter months. This applies to any EV, and the amount of range lost is directly related to how cold the outside air temp is. Also, the SoC will drop as cell temperature drops.
I am not preconditioning at all. I wanted to eliminate that variable that people claim. Preconditioning from the outlet and battery both cost money anyway. I'm not charging either that doesn't matter. When I do charge at the end of the week it will be at 240-40amps.
The point is the idea of calculating cost of real world use so it can be compared to a fuel vehicle. Not just efficiency of driven miles.
Oddly the car is still at 55% right now without being driven. I assumed it would drop more over the last 8hrs but it seems to have slowed down. Yesterday it lost 8% range.
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But not preconditioning at those temperatures is skewing the numbers. This would be similar to constantly driving your ICE a short distance in cold temperatures, so that the engine never has a chance to get warm, and then wondering why you got such poor fuel economy.
In other words, your comparison should involve preconditioning on utility power since that is what the manufacturer intended when operating at those temps. After all, the manufacturer does know that doing so for merely 15 minutes will make a dramatic difference so that the heat pump isn't trying to produce heat without any help from the batteries or motors. The key is to not question the method to the madness and instead follow the manufacturer's tips/recommendations.
The more I hear about these cold temperature examples, the more it reinforces what I've been saying about the importance of using the energy before departure, rather than using even more energy after departure.
Lets assume that the 35% drop in SoC equates to 25 kWh, which was the amount of energy required to travel 47 miles in 3 days. If in ideal conditions, that 25 kWh can get you around 100 miles, that suggests to me that around 13 kWh was consumed due to inefficiencies. Lets assume that 20% of the 25 kWh was consumed due to the winter's effect on EV range, so that makes up for 5 out of the 13 kWh, leaving 8 kWh of energy unaccounted for. In my opinion, some/most of this 8 kWh of energy was wasted due to making the heat pump produce heat from practically nothing since the battery and motors were probably below freezing already. If we assume that preconditioning was used for 15 minutes before departing on each day, while plugged into your 10kW charger, that would consume a total of about 6 kWh over the course of 3 days.
So consume 6 kWh before departing to potentially save a chunk of that 13 kWh is the point I'm trying to make.
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I get what you are saying but I do drive my gas vehicle like this. I don't plug my gas vehicle into a fuel pump and not count the fuel it is using to warm up before I drive. And I don't have a heat pump in my tesla.
You probably drive your ICE the way the manufacturer suggests... but you're not interested in following what Tesla suggests?
Wait.. huh? Your Tesla doesn't have a heat pump? This is the MY forum..
I totally missed that he has a P3D and not a Y. That explains the winter issue.
I don't really agree with you about preconditioning, though. That is recommended for comfort not efficiency. I've seen really high energy usage in the charger when conditioning while plugged in that would ultimately even out vs warming while driving.
Well yeah, I thought it was safe to assume that we’re all talking about MY’s in this part of the forum.
I’m afraid to say that you’re incorrect regarding preconditioning being for comfort, not efficiency. It’s quite the opposite in fact, especially when dealing with sub freezing temps.
This is from the cold weather best practices section, straight out of the Tesla MY manual...
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This is true.
No, he's not incorrect. Let's go through that section of the manual to understand what it's talking about.
Quote: "...and to achieve maximum range and performance, it is helpful to warm the cabin and battery before you leave"
That is talking about a tactic "to achieve maximum range", as it says. This is about if you are trying to extend the distance you can drive once you have unplugged. So it is about the practical traveling distance aspect of pre-using more of that energy from the wall so that it's not having to pull as much from the battery once it is underway, which would have reduced your driving range.
That is unrelated and actually unhelpful for the question of which way in total uses more energy. If you just take off and drive, the car obviously will only heat as much as it needs, pulling from its own battery reserves. But pre-heating from your house will usually do more than is needed, thereby wasting some extra energy on the whole.
I have to disagree. The manual doesn't mention anything having to do with comfort in it's language when it's talking about preconditioning in cold weather.
So if not efficiency, what is it talking about when it refers to benefiting range and performance?
The BMS will still warm the battery if it isn't plugged in, therefore using it's own energy (and by your thinking, reducing it's range), it's just more economical with its energy usage when doing so. So apparently, it is about increasing range and performance whether you're plugged in or not.
Also, where does it mention that it is best to have it plugged in for best preconditioning results? The language suggests to me that, whether or not the car is plugged in, range and performance will benefit from preconditioning, due to an increase in...?
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It doesn't have to use the word "comfort". But it also doesn't use the word "efficient" or "efficiency", which is what you are claiming, does it?I literally just explained that!
By getting the heat into the car before you disconnect it, the car will have more independent driving range without having to suck that extra energy from its battery later. The manual says that: "to increase maximum range".
Because two of the three most frequent gripes from the public about electric cars are 1. range and 2. range. (The third is charging time.) Haven't you seen how many threads there are constantly across all the models of people getting worried/upset/angry and talking about class action suits from how the energy use while driving is really high and the car's total driving range while away from home is less than what they were expecting, and they were unsatisfied with that? THAT is by far what people are most concerned about. So when you ask where does it say it is "best" to do that while plugged in? That's where. It's everyone's gripes. Most people don't care as much about this nitpicking of whether it's most efficient one way or the other. What is "best" for them is being able to use the car and have enough driving range away from home, and preheating at home does increase that independent range once you unplug.
I updated my previous post to clarify that it does warm the battery still when it's unplugged, which is apparently for increasing range and performance. So if it's consuming battery energy to increase range, what does that tell you?
Performance is another way of saying efficiency when talking about an electrical system..
It tells us that having no regen at all does kind of hurt range because it forces always using the brake pads and is not able to recover anything when slowing down, so there is some level of warming up out of the extremely cold that helps that operation, but that doesn't extend without limit to using huge amounts of energy to get the battery really hot.
Heh, no, generally not, or they would have said efficiency. Performance is...performance. When the battery is really cold, it will also limit power output, reducing acceleration. You know--performance. And for many people, the driving feel is an important part of how the car performs, so they don't like the partially limited regen feel.Similar threads
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