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Vehicle 2 Grid yet again

Discussion in 'TSLA Investor Discussions' started by mrmage, Jul 12, 2019.

  1. mrmage

    mrmage Member

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    I was thinking about a powerwall priced at $7k, and realized that Tesla could easily add $20k to $40k of extra value to its cars by adding vehicle to home energy capability.

    I understand that using the car to power the home was dismissed by Tesla before, but Tesla should consider this simple and low risk addition. It is an absolute waste of green (my wallet and the environment) to produce an extra set of batteries for home charging when a car can provide both.

    If Tesla does not have this, my next EV might be one that has V2H instead of Tesla because this is the greener solution. Having at least one car that provides 50 to 100 kwh battery backup for my house would be utterly compelling.

    Nissan sees Leaf as home energy source, says Tesla big battery "waste of resources" | The Driven
     
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  2. dqd88

    dqd88 Member

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    #2 dqd88, Jul 12, 2019
    Last edited: Jul 12, 2019
    I don't get it. Seems like a limited use case. Like a backup generator.
    But if there is demand for it then sure. I wonder how feasible it is to implement.

    “It’s a complete waste of resources because what we can do is have cars that are also batteries and those cars are parked most of the time,” Thomas said.

    One thing that this Thomas guy doesn't get is that the goal is that the cars won't be parked most of the time once FSD is complete and there is a high economic incentive to have the cars operating constantly. If/when the rideshare network is viable, the cars' optimal utility will be met as a people mover rather than a "mobile battery".
     
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  3. KarenRei

    KarenRei ᴉǝɹuǝɹɐʞ

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    #3 KarenRei, Jul 12, 2019
    Last edited: Jul 12, 2019
    Battery packs have a given cycle life designed around the vehicle's expected needs. Should you prematurely age your vehicle's battery? Or should vehicle batteries be overdesigned for excessive cycle lives, causing them to cost more and have shorter ranges?

    Car V2G makes no sense. You're probably not even on a feeder line that the power company wants to buffer. Cars as a home backup in emergencies? Sure. Cars "smart charging" when rates are low? Sure. V2G? No. Grid batteries should be where the grid wants them, and designed around grid needs, incl. stressing longevity and cost over energy density.

    IMHO.
     
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  4. Fact Checking

    Fact Checking Active Member

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    Battery longevity cost aside (which is a valid concern), there's an important exception though: when the vehicle is parked at work then it's near consumers of substantial amounts of electricity. "Transporting" some of the excess power that was stored in the car's batteries overnight from cheap baseline generator power and feeding it into office, business and industrial centers that consume peak electricity during the day could be useful, and not just during emergencies.

    And the typical daily pattern that cars follow is that they park ~23 hours and are used ~1 hour. Where the car is parked during those 23 hours matters.
     
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  5. matejpi

    matejpi Member

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    I don't agree. V2G makes a ton of sense if we are going from FF generated electricity to renewable sources. Like Nissan said. It's a waste of material (=battery) to be only used for transportation and I think Tesla knows that. The beauty of OTA and Tesla is that, they can enable this feature whenever they want.

    Electricity storage is much bigger business than car industry.
     
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  6. Artful Dodger

    Artful Dodger ♫ sniffin' the mornin' cool ♫

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    The straight forward, pragmatic answer as to why Telsa hasn't implemented V2G or V2H is that they have a fleet of large batteries out their with access to free supercharging.

    A little work on their biling system, and Tesla can do it.
     
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  7. KarenRei

    KarenRei ᴉǝɹuǝɹɐʞ

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    #7 KarenRei, Jul 12, 2019
    Last edited: Jul 12, 2019
    The battery will almost always be used to its full cycling potential (barring the premature loss of the vehicle in an accident) - V2G or no V2G. No potential is being wasted. What strikes me as dumb is preemptively aging the battery pack, which will bare minimum require a battery replacement, and would usually cause a whole car to get thrown away years earlier than it otherwise wouldn't have been (since most people probably won't do a battery swap on an old car). What also strikes me as dumb is dedicating cycles of cells focused on energy density to a task that would be better suited to cycles of cells focused on longevity and cost.

    Cell cycle lives are finite. You can't get around this. If you allocate a cycle to one thing (e.g. V2G) then you're not allocating it to something else (like driving). You make more cycles by making more cells. Do you want said more cells/cycles to be ones focused on longevity and cost, and installed where they'll do the most good, and always connected to the grid when the grid will need them? Or do you want said cells/cycles to be focused on energy density instead, and always in a car, which may or may not be connected to the grid at a location where they may or may not be needed?

    A much better option is smart charging. Like V2G, but without actually outputting power. You tell the car how much of a charge you want and when you want it, and it decides - based on grid rates, reflecting grid needs - when to actually do said charging. Smart charging doesn't impose any extra cycles on your battery pack, but it keeps vehicles from charging (unless owner needs demand it) when the grid is stressed. It of course, like V2G, requires a smart grid which can transmit power needs and forecasts.
     
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  8. mongo

    mongo Well-Known Member

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    Powerwall is 14kWh * $125/kWh = $1,750 worth of battery leaving $5,250 for inverter (5kw continuous 7kW peak), balance of plant, manufacturing, profit, NRE, and warranty coverage.
    To make the cars V2G would require something similar either integrated in the car (raising the sales price on all) or integrated into the building at similar costs.

    Using V2G to cut the peak demand rate for commercial buildings has been tested previously and has merit.

    For the home use scenario, the car is mispositioned to store solar production or provide backup power five days a week.

    Tesla's software can prevent exporting power, so free supercharging misuse is not a concern in an officially supported V2G solution.
     
  9. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    Yeah. I'm sure any company will love to have their electricity paid for from the employees' home electric bill.
     
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  10. Artful Dodger

    Artful Dodger ♫ sniffin' the mornin' cool ♫

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    #10 Artful Dodger, Jul 12, 2019
    Last edited: Jul 12, 2019
    You don't want to block it; you want to charge for any energy received from the Supercharger network, while still allowing V2H, solar charging, grid peakshaving and TOU arbitrage.

    Telsa will need to write some software to support all this, without blocking free SC use for authorized vehicles. I'm certain its low priority for them right now. Some competition will change that.

    EDIT: There will need to be a bty use accounting feature. Not that the owner isn't entitled to use their bty as they choose, but that use shouldn't be allowed to arbitarily extend Tesla's bty warranty exposure.

    The use case I see is a Tesla Pickup truck that is used to tow the family travel trailer. It mostly sits for 10+ mths per year, then is in heavy use for a brief period. Why not have it's bty pack backing up your regular home for those other 10 mths?
     
  11. mongo

    mongo Well-Known Member

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    OT
    Nissan testing peak-shaving services from Leaf EV to building

    I failed to find a better link, but the setup I recall was 4 or 5 (Leafs?) used to flatten peak load at their employer, for which, I believe, they recieved compensation and free charging at the off peak times (may have even covered the lease).

    So the only downside was accelerated pack aging.
     
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  12. Lycanthrope

    Lycanthrope Ask Dr Stupid...

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    On Leaf packs that have an appalling degradations history too :eek:
     
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  13. Christine600

    Christine600 Member

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    I hope not!

    In addition to the other posts about this issue...

    If so I'd need a battery replacement earlier. And that is a hassle and a financial setback. So they would have to pay me enough to get a new TMX every 3rd year or so. Or I would not participate.

    Also - how could I let my battery run down and at the same time have enough power to do the things I need my car for? My life is much more complicated than driving to/from work only. Cannot see a solution here that would work for me.

    So I think it would be better for the planet if those needing a power backup/cache at home bought powerwalls. Or similar. Wasting money an energy to make all cars powerwalls when only a few need this function is not the way to go.
     
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  14. MP3Mike

    MP3Mike Well-Known Member

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    The first thing Tesla would have to do is change their battery warranty since the warranty doesn't cover any damage/degradation cause by "Using the vehicle as a stationary power source".

    I doubt many people would give up their battery warranty to supply backup power to their house occasionally.
     
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  15. UncaNed

    UncaNed Member

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    Would it really age my 75 KWH car battery much to use a Powerwall worth's of capacity near the center of the battery's range for V2G? I'd feel like I was getting a free Powerwall up front, no extra battery replacement expense till years later. Part of a Distributed Solar arrangement, perhaps. My car is often parked at the right times for that, and usually used only for short trips around town.

    I'd see it as value added to Tesla's vehicles, unless it cost way more to add V2G capability.
     
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  16. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I'd say yes. The battery life won't be shorter, but the miles you can drive your car on that battery will be. Especially because car batteries are different than Powerwall batteries as they are designed to do a different job.
     
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  17. MP3Mike

    MP3Mike Well-Known Member

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    It would age the battery about the same as driving your car ~50 miles. So if you did it every day it would be like driving your car an extra 18k miles per year. So in other words: yes. (And a Model 3 only has a battery warranty covering 100k/120k miles. So you could burn through your battery warranty really quickly.)
     
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  18. Christine600

    Christine600 Member

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    If you end up having to supercharge more then you might hit the supercharge limit for your battery and get permanently reduced supercharing speed for the rest of the batterys life. This issue is beeing duscussed on the Norwegian elbil forum.

    This would affect the usability of your car - and it's resale value.
     
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  19. ggr

    ggr Roadster R80 537, SigS P85 29, M3P 80k

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  20. Rockster

    Rockster Active Member

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    Isn't battery backup for the home more complicated than just enabling V2G in the car? It seems that any customer wanting to use their vehicle as home battery backup in case of grid failure would need some sort of isolation cutoff installed so that they're not energizing the grid with their car during a power outage.
     
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