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We allready have 85 kWh PowerWall

Discussion in 'Tesla Energy' started by Matias, May 1, 2015.

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  1. Matias

    Matias Active Member

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    Why isn't Tesla making hardware to use our cars as a storage?

    Supercharging is not a problem. Car could keep track on supercharging and disable using it as energy for house.
     
  2. lolachampcar

    lolachampcar Active Member

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    standby small
    It is no coincidence that the PW is a 350-400 Vdc battery (sound familiar???). If it were going to play nicely with existing inverter technology, it would have been 48 Vdc (see WK's threads on using an MS battery for his home solar system).
    We know the power connector on MS supports direct DC access to the battery (SuperCharging) so there is no reason to think the power can not go the other direction.
    What we need is a smart inverter that can (1) switch the grid to house on and off seamlessly, (2) manage the PV array at MPT while sending the excess DC to the battery directly needing only a small buck/boost circuit, (3) the ability to manage both a stationary battery and a MS in parallel and (4) the communications necessary to get the MS to play along.

    This is exactly how Musk/Tesla does stuff. He is using the car company to fund the battery building to take on carbon on the road and at the utility.
     
  3. voidptr

    voidptr Member

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    Why would I want to put more cycles on the battery in the car than I have to, or run the risk of having less charge in the car when I want to run out than I expected?

    Also, during the day the car isn't in the garage, and at night it's charging. My car is in exactly the wrong place at the wrong times for any kind of solar load shifting or grid demand arbitrage.
     
  4. Evbwcaer

    Evbwcaer Member

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    I really feel that Elon's goal is to lower CO2 levels, probably above all else. It makes me think that there must be some technical challenge or other hurdle for this to be a reality. When you think they are selling a 10kwh battery, they have decided it does not need to be that big in KwH to be big in impact. I just can't see taking/adding 10kwh out of an 85kwh pack stressing the pack much.
    I'd guess the average Model S spends 99% of its life in the 50-80% SOC level, far from the extremes that stress a battery.
     
  5. Saghost

    Saghost Active Member

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    #5 Saghost, May 1, 2015
    Last edited: May 1, 2015
    This, I like.

    An integrated module that has a built in transfer switch for critical loads and charges the car using Supercharger protocols and a dc-dc converter from the string DC or the grid through a bidirectional inverter/charger - additional home backup battery optional.
    Walter
     
  6. vdiv

    vdiv Chief Grump

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    Well, Tesla can start by adding more than one 12V power outlet to its 5+2 passenger vehicle... (the Volt has three, other vehicles now sprout integrated 120V inverters with NEMA 5-15 outlets)

    The mobile aspect of that 85 kWh "powerwall" should not be underestimated as the power can be used in various places on a temporal basis. The thinking at Tesla may be that people will be unwilling to use their cars in such a manner and risk being stranded. Still the option should be there.
     
  7. SmartElectric

    SmartElectric Active Member

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    The Tesla Powerwall is designed to combine together up to 8 modules. Tesla is selling a home battery from 7-80kWh depending on how you choose and connect them...

    The same goes for the Powerpack from 100kWh and beyond to mW level integrated battery systems.
     
  8. Evbwcaer

    Evbwcaer Member

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    Point taken. Does anybody know the basics of degradation on how using an MS pack would likely end up? Say you never went below or over some conservative SOC levels outside of driving.
     
  9. austinEV

    austinEV Active Member

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    It is true that most people have that problem. But, some people work from home, some people work at night, some people don't work at all, and there is always weekends. If vehicle-to-grid were an option, I would be probably using it on weekends (if I had solar, which i do not).

    I think the real reason there is no (released) vehicle-to-grid is that they want to manage perceptions. If the battery life is great for just driving, then they want those great impressions for the brand and EV's. If driving+daily cycling is much worse for battery life they would prefer not to mess with it. This is my feeling. Better to sell a separate $3k device special built for that.
     
  10. CHG-ON

    CHG-ON Still in love after all these miles

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    For me, living in the Redwoods, where trees take out power every winter, it would be awesome to use the car to fire up the house short term. I wouldn't want to do it long term. I have a generator for that. But how sweet to go out, flip a switch or two have have the house come back up. Then I could fire up the generator, warm it up, get it stable, and then switch over. Unfortunately, I don't have an auto switching Nat Gas generator because I spent all my money on the damn car!!:biggrin:

    Such first world problems...
     
  11. DFibRL8R

    DFibRL8R Member

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    For me, I would really like to have the ability to use the Tesla battery for emergency power supply (grid failure) rather than spend the money on buying and maintaing a fossil fuel emergency generator or buying more batteries for this purpose. Given the inherent portability of the car, an onwer could even drive to a neigbor's house (or supercharger etc.), return to their home and supply needed power for critical loads for a more extended outage. I already have solar and even have an SMA Sunny Boy inverter with a backup outlet so I can use a little power directly from the panels in a grid outage (but this is only when the sun is shining and is around 1500 watts max output).
    In my location, the grid is very reliable (we typically get 2-3 brief outages per year) and the Power company does not offer the incentives to allow me to make/save money by time of use gymnastics. I understand why Tesla might not want owners to tax the battery by daily use for this purpose but adding an emergency feature for occasional use I believe would add value to the car.
     
  12. ThosEM

    ThosEM Space Weatherman

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    Since the roadster came out I have thought this would be a standard feature for any EV. I am very disappointed Tesla thinks it justifies the purchase of additional batteries.
     
  13. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    More importantly Tesla is trying to make and sell cheap batteries. The more successful Tesla is in its mission, the lower the value of V2G. And as someone pointed out up thread cars are anti-cyclical and mobile. How many times do we point out to people that cars are anti cyclical so help the grid as a demand sink?

    Elon Musk tweeted $250/kWh for the PowerPack. It can only get cheaper from here. V2G requires cars to be plugged in when utilities need demand and supply. So V2G would need massive deployment of charging points, while also adding unpredictability to grid management. Or, utilities can buy PowerPacks and deploy them how they see fit.

    On top of all that, V2G is using automotive batteries to provide grid services, which have different performance requirements.

    If at some point battery technology stalls out at a cost that allows a self-sustaining market in PEVs but prevents PEVs from taking over, then it might be worth it to try and eke out some extra value. But even then, since much of the economic value of V2G can come from it being only a demand sink ("G2V"), I still don't see anything coming from it.
     
  14. scottm

    scottm Active Member

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    If you're like me and live in the Tesla, who needs PowerAll at all? What house!?
     

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