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  1. A

    Shorting Oil, Hedging Tesla

    I expect to be served? What does that mean/ How would this thread serve me? It has been amusing as all get out, I'll say that. But I didn't ask to be amused. It just worked out that way. What services are offered? What services have I requested? And I don't particularly care whether anyone here...
  2. A

    Does regen braking use more power? [Update: no, it does not]

    That pedal is the accelerator/decelerator pedal. Push it towards the firewall and the car accelerates. Let it come back from the firewall and the car slows down. Deceleration is maximum when the pedal is at the rearmost limit of travel. Learn to "feather" the pedal to drive your car with minimum...
  3. A

    Does regen braking use more power? [Update: no, it does not]

    I guess so. Regen recovers not only kinetic energy but potential energy. This is how you are able to leave a location and arrive at your destination with the battery more charged than it was when you left. And why you can sometimes see a remaining range display of 999 miles.
  4. A

    Shorting Oil, Hedging Tesla

    This is true only if you use the utility as the "battery" and today we do as we don't have any alternative. When this does happen then there is a potential to shed T&D. This is currently a hot topic. Microgrids are receiving a lot of attention. If one upgrades his rooftop solar, as I will be...
  5. A

    Shorting Oil, Hedging Tesla

    Actually 1000 °C is the lower boundary defining the beginning of the domain of "high temperature materials" and the practical upper limit for steels. But materials that function at higher temperatures are very important in energy production as efficiency depends on the difference in temperature...
  6. A

    Winter Range and Charging

    If the air conditioner can draw heat from the cabin and transfer it to the ambient it can also draw heat from the ambient and transfer it to the cabin but I have been assured that this is not done in the X. Assured by Elon Musk? No so I can't really say but I have never seen any behaviour in the...
  7. A

    Shorting Oil, Hedging Tesla

    That's about right for residential but on the industrial scale I think I heard $0.30 in a video.
  8. A

    Shorting Oil, Hedging Tesla

    For eons we have relied on nature (the sun) to transfer electrons from oxygen to carbon and then let them go back to oxygen by burning "fuel". There are tons of advantages to this as a unit mass of carbon contains lots of energy, is relatively stable, the rate of extraction is easily controlled...
  9. A

    Shorting Oil, Hedging Tesla

    Respect is not obtained by request or demand. It is earned. Let's see how many of you disagree with that.
  10. A

    12V battery what is the use

    I went ba=ck and looked at the OP. It asked what the 12V receptacle was for and most everyone interpreted this as asking what the 12 V battery is for. Someone suggested that the 12V receptacle is for portable stoves, refrigerators, TV's, kettle's etc. No it's not for those as it has only a 15 A...
  11. A

    Range/Navigation

    No. What it means is that if you continued to drive under the same conditions and using the same technique as pertained over the last 30 miles (or 10 or 5) that it would take 6% more juice than is in the battery to get you to your destination, Thus you must get more coulombs into the battery...
  12. A

    Winter Range and Charging

    Some observations (X100D - 2 row) With the car in a cold garage with the fan at 4 and external air being admitted the heater(s) at turn on draw about 2200 W for about 1 minute. The draw then steps down over the next 5 minutes to about 1100 watts, then starts to oscillate around 1300 W. The...
  13. A

    Doors not opening fully first thing

    That would be easier than hefting. If I remember, I'll try that.
  14. A

    Shorting Oil, Hedging Tesla

    Does a real troll care? Seems I wound up here with some comments on electron transfer and then noted some of the wild stuff that gets posted here. I don't think these are private threads so if I wish to post something that runs contrary to the accepted orthodoxy as prescribed by those that...
  15. A

    Doors not opening fully first thing

    Didn't know any of that. Probably plainly stated in the manual. I'm old enough that I don't embarrass very easily and fumbling in my pocket for the fob is a PITA so I'll probably just continue to push. It's not that hard. Not to mention the fact that the next time it comes up I will have long...
  16. A

    Shorting Oil, Hedging Tesla

    Clearly I did. Clearly you didn't. Kodak was mentioned as a model but it's not a good one as Kodak was a razor-blade business. Had Kodak successfully developed digital cameras (their efforts were pretty pathetic) that would still not have replaced their film and processing chemical sales...
  17. A

    Shorting Oil, Hedging Tesla

    Isn't it a little early to suggest that 1% of automobiles on the that use 70% less lube are disrupting the market? But they better be looking to the future. You don't see many people selling phonograph needles or buggy whips these days.
  18. A

    Shorting Oil, Hedging Tesla

    I get a real chuckle out of the increasing number of people who waste the time it takes to "disagree" with a couple of my posts. If they are really disagreeing they must feel that basing financial decisions on whimsy is a good idea. Amusement aside, I hope you guys don't lose your shirts!
  19. A

    What Tesla should have done with range.

    Range = SoC*miles_per_unit_SoC. I wouldn't glorify something that simple with the label "science". It's grammar school math. Or at least the second factor is. You divide the miles you went by the amount of SoC you used. Now estimating SoC is based on one important scientific fact - that the...
  20. A

    Doors not opening fully first thing

    Yes. It's not that they are heavy (well, they are but there are springs in the roof that take up the weight) it's the resistance in the gearing.
  21. A

    Doors not opening fully first thing

    Just push. There is more resistance than with the rear door but you can get them fully open this way. Note that I am talking about the situation where they are quite far open - just not as far as you like. I am not talking about a situation where they open an inch or two and stop. I do not...
  22. A

    12V battery replacement, whos had to do one?

    I'd start by putting a battery charger on it. What this might or might not do I can't say. If the battery has failed it will let you open the doors and perhaps even turn the car on to the point where Tesla can ping it and download logs. If the battery will hold charge you might even be able to...
  23. A

    Doors not opening fully first thing

    It is trivially, if not very satisfactorially explained: software bug. Some flag or some register gets set when you are in the tight garage which doesn't get cleared. The fix is to notify Tesla so they can change the code to prevent this. Otherwise you might try pushing the lock button on the...
  24. A

    12V battery replacement, whos had to do one?

    This is the nature of the modern lead acid battery. They don't, in normal applications, give much if any warning. The Tesla application is not normal and they have pretty sophisticated monitoring designed to give you weeks of warning. Guess that failed here. Have you tried jumping it?
  25. A

    What Tesla should have done with range.

    Miles and percent convey the same information. The car is continually estimating the battery's SoC. The displayed range is simply the SoC (in percent) multiplied by the miles per percent. The problem with the miles display is that there are several mile per percent value and it is easy to be...
  26. A

    What Tesla should have done with range.

    Let's suppose your 90% range is 285. That implies 100% range of 317 miles which is three miles per percent. Thus just because of rounding you can have 3 miles displayed variation.
  27. A

    Review of Honda Clarity Fuel Cell Vehicle (plus planned switch to Tesla)

    OP's excellent review was divided into three parts. The car, its performance and fueling. He gave good overall marks in the first two categories and a fail in the last. FCEVs have been held back because of fueling and there are a couple of aspects to this 1. A FCEV cannot fuel at the owners home...
  28. A

    What Tesla should have done with range.

    It does. There are a couple of ways to increase range. One, and this is, I think, what you have in mind, is to simply move the E and F marks on the gas gauge farther apart i.e. to make some of the low end and high end buffers available to the driver. This, of course, reduces the safety factor...
  29. A

    Winter Range and Charging

    The drag force on a car with coefficient of drag Cd and cross sectional area A traveling at speed v through air at density rho is F = Cd*A*rho*v^2 If the car travels distance x then F*x units of energy must be expended to overcome this drag but the energy consumed per unit distance traveled to...
  30. A

    Cabin Heat / Speed Interplay on kWh/mile

    Not misinterpreting but don't read too much into those numbers. For starters they were for an X, not a 3, sittting in a not particularly cold garage but on a cold day. They were also power measured at the input to the car and thus include rectifier/inverter loss and thus need to be decreased by...
  31. A

    Cabin Heat / Speed Interplay on kWh/mile

    No apology necessary. Lot's of info goes flying by here and it is very easy to miss something. But thanks.
  32. A

    Cabin Heat / Speed Interplay on kWh/mile

    Again, you miss the point. The purpose of the analysis was to lend insight. OP got that. You don't seem to be able to. Why don't you just leave it at that? But one more time, Sam: No one ever said the model was current, accurate or good down to low speed. It does seem to be representative at...
  33. A

    Cabin Heat / Speed Interplay on kWh/mile

    That depends on the nature of the consumption power relationship. If that's hard to differentiate - well we can always use machine approximation. There is and it has been mentioned at least 5 times in this thread.
  34. A

    Cabin Heat / Speed Interplay on kWh/mile

    No, I am not telling you that. I am telling you that it takes the same amount of energy to raise 2000 cubic feet of air though a given ∆T whether you do it with a stream of air at 100 ° or one at 140 °F. Enthalpy is conserved. If m1 and m2 be two thermal masses and and ∆T2 two temperature...
  35. A

    Cabin Heat / Speed Interplay on kWh/mile

    Well, honestly, in my view, you didn't read the posts very carefully. To begin with OP is interested in a gedanken experiment in order to give himself insight as to whether there is a speed which will give him fewer Wh used for a trip than any other speed. In No. 15 elijah showed the equation...
  36. A

    Cabin Heat / Speed Interplay on kWh/mile

    The temperature of the air that comes out of the vent doesn't enter into the calculation. Energy is conserved. The relatively small volume of quite hot air transfers its heat to the larger volume of air in the chamber being heated. What counts is how much room air is heated through the rise, IOW...
  37. A

    Tesla wall charger users. What size wire is your charger using?

    Which is why, if you use a 6-3 cable with white and black wires, you must mark the white one with red tape at both ends. Excuse the nerdy EE stuff but it is actually measuring the source resistance i.e. the total resistance between the source and the charger. It cannot know what the cause of...
  38. A

    Powerwall and Pumps

    How big is the heat pump? 1 kW/ton is a general rule of thumb.
  39. A

    Powerwall and Pumps

    Did I say I used a standard meter? The numbers I reported are true. Beyond that I'd guess, as I am not a motor expert, that locked rotor current is almost in phase with the voltage because only the leakage inductance is there to produce VARS. The big VARS don't come until the rotor starts to...
  40. A

    Cabin Heat / Speed Interplay on kWh/mile

    100/35 = 2.85 times as much but who would heat his car (or room) to 100 °F? Let's look into that a little further. Lets suppose the cabin contains 200 ft^3 of air (I expect the cabin of a 3 is smaller than that) and that we change it 10 times per hour. That's 2000 ft^3/h. The formula for the...
  41. A

    Cabin Heat / Speed Interplay on kWh/mile

    That is true at higher speeds as the plot in No. 23 shows. Note that the curves become farther and farther apart as speed increases. For example, at 65 mpH they are about 700 W apart. At 60, only 600. As these curves are 10 Wh/mi apart that means we turn on the heater to 1000W at 65 mph we...
  42. A

    Powerwall and Pumps

    I just checked my well pump. It draws draws 1.7 kw running and only 2 at startup. Note that the latter is measured in a 1 second window so the inrush for the first fraction of a second would be higher than that but certainly not more than 3 -4 times the running load (i.e. max 6.8 kw). I'd...
  43. A

    Cabin Heat / Speed Interplay on kWh/mile

    No, it is not true. One can drive any speed he wants and have at least some control over what the heater does independently of that but the Wh/mi, inversely proportional to the efficiency couples those two i.e. Wh/mi = P/v + v^2/30 + 5*v/6 + 120 in which P is the demand of the heater in...
  44. A

    Shorting Oil, Hedging Tesla

    What I conclude from the last couple of posts is that I should go long on lithium!
  45. A

    Shorting Oil, Hedging Tesla

    Cracking is breaking down long chains into shorter ones. In natural gas the molecules are short so to make useful things from them one needs to do the opposite e.g. polymerize.
  46. A

    Winter Range and Charging

    The 3 row X's have a second evaporator than the two row ones but I don't know about a second heater. The cabin isn't any bigger so more heating or cooling isn't required. It's a question of getting the heat (or cold) back to the third row. The fact that Tesla runs a refrigerant line rather than...
  47. A

    Shorting Oil, Hedging Tesla

    Wouldn't we all! I remember a highly respected (throughout our industry) colleague of mine, in speaking of complex systems, opining that if you can't ultimately explain something on the back of a cocktail napkin it probably isn't worth doing. In my experience this has proven to be true many...
  48. A

    Shorting Oil, Hedging Tesla

    But why go to that source if there be a glut of oil? Wow! That's the kind of solid basis that I like to have underpinning my financial decisions. And it makes me very happy that I have financial advisers who are willing to wade through stuff like this so I don't have to. Gives me a headache!
  49. A

    Cabin Heat / Speed Interplay on kWh/mile

    The heater may be capable of 4 kW or so but it will seldom run at that rate. Think about it for a minute. A kW is over a quarter of a ton of heating. Do you need a quarter of a ton to keep the tiny cabin of your car warm? For perspective, it's just freezing here at the moment and my 8 ton heat...
  50. A

    Experiencing regenerative braking issues after 1 year

    It's clear that what is clear to me isn't clear to you so suggest you just add me to your "ignore" list.

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