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Grid Charge Powerwall with Solar

Discussion in 'Tesla Energy' started by Fonzi03, Nov 11, 2019.

  1. Fonzi03

    Fonzi03 Member

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    I am having a system installed and have just been informed I will be locked out of grid charging.

    Now as far as ITC is concerned I full understand so skip right passed that please.

    To my understand I can't charge from the grid because I could then also discharge to the grid. IE pay off peak then sell on peak and would make money. So my question is can I charge off peak discharge only to house on peak I don't ever need to discharge to grid.

    I would send all produced solar to the grid I would never need to charge the battery with solar in this instance as my net cost is the same as my net sell therefore I wouldn't be losing anything.

    Yes I also understand the ~10% round trip loss however that would be the case regardless of if I charged from my panels or the grid then discharged so this is a moot point for me.
     
  2. power.saver

    power.saver Supporting Member

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    Tesla does not let you do that if you have solar in the US. So no, you can't do that.
     
  3. boaterva

    boaterva Supporting Member

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    Been discussed dozens of times. What’s new here?
     
  4. jjrandorin

    jjrandorin Another BMW convert

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    Not in the US you cant. tesla does not allow it. Maybe it changes at some point but dont plan on it, if you have so

    No, in large part because of the part you said "skip right past that please". Tesla does not allow it in the US for batteries with solar, so there is no convincing, or configuring, or speculating about what we would do, until they allow it.[/QUOTE]
     
  5. JayClark

    JayClark Member

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    #5 JayClark, Nov 12, 2019
    Last edited: Nov 12, 2019
    Yes, not a new situation in regard to not being able to charge from the grid. Pretty standard requirement for most utilities in most states in major metropolitan areas. It seems like the way the situation played out for Telsla, for them to get these PW systems off the ground, they had to abide by the utility requirements. As far as I know, I think the requirements are the same for battery systems from other vendors.

    Also, it really shouldn't be considered a mute point - pulling energy from the grid just to put "less" of it back later is hard to build a case for, unless the utility has some very "friendly" buy-back rate plans (which they don't in Arizona), at least not with APS and SRP. Additionally, from my view point the added charge/discharge cycles, on a very expensive piece of PW equipment, that shortens it's life, also hard for me to justify with my investment.

    In fact, after experimenting with my system, I also only store & extract the minimum Solar (with a little extra slack) into the PWs, just putting in enough to zero out my peak period usage by pulling back out of the PW only what I need during those peak windows. Along the same line of thought about not charging from the grid, and given my utility rate plan, it's also hard to make a financial case for putting extra solar into charging the PW, vs letting the extra solar simply run the house directly until the PW is needed to run the house after the sun goes down for just covering peak periods.

    I actually think (even though I knew the situation going into my purchase) I remember being a little irritated about some of these limitations myself about not being allowed to charge from the grid as I waited for my system to be installed, but once it was up and running, and I saw the system in action and saw how it all works, and my bills, for whatever reason it seems to make sense now, and I can't remember why I was so amped up about wanting to charge from the grid, but I'm reminded that I think I was a bit.
     
  6. Fonzi03

    Fonzi03 Member

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    Well sorry for bringing up a topic that has been discussed dozens of times however I know there are ways around it...

    Now to throw a huge monkey wrench in the situation I just got approval by my power company to charge from the grid, they actually prefer it. They have sent a note to Tesla telling them to software unlock my powerwall. My solar company has the info and said Tesla would be willing to do it if the power company allowed it.
     
  7. Fonzi03

    Fonzi03 Member

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    SRP actually does has great buyback it's 1-1 so not sure what you mean by the rates aren't good?

    I plan to charge at night just after peak, at which point I have a ~80% cap I'd set. I would then discharge at peak morning in winter or if we have a power outage I now have backup also. During peak in AM o plan to sell back any excess production which would be at higher rates. Therefore saving money because the beginning of AM peak hours I would not have any production.

    The battery has an unlimited guarantee so if any extra cycles caused it to depreciate faster then it's covered anyways.
     
  8. jjrandorin

    jjrandorin Another BMW convert

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    Not sure where your plan is coming from, because you will not be able to "charge at night just after peak" if you have solar, in the current iteration of teslas software.
     
  9. Fonzi03

    Fonzi03 Member

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    My power company has contacted Tesla and told them to remove the restriction as they want their customer to be able to charge from the grid. Before calling my power company Teslas claim was the only reason they don't allow it is because of the power companies. My power companies Tesla liaison is reaching out to Tesla today along with my solar installer to make sure this happens.

    Anyone with a powerwall know if I can create multiple schedules for charging/discharging? I have heard both yes and no. It would be much easier for me to not have to create a schedule and learn their API to program it into my Crestron control system.
     
    • Like x 1
  10. JayClark

    JayClark Member

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    #10 JayClark, Nov 13, 2019
    Last edited: Nov 13, 2019
    Interesting, do you still have the SRP link to the Service Plan PDF? It must be a different one that the only one I can find. I analyzed their purchase plan (SRP Customer Solar Export Plan - link from the SRP here) and it couldn't come close to paying off in my situation since the buy-back was always-and-only at most 2.81 cents kWh (never more than that) even during peak, yet the cheapest off peak rates SRP charges the customer during any season is basically 7 cents, and peak period rates are as high as 21 cents. Those are only what SRP charges the customer, they never buy-back at those rates, the SRP plan explicitly states they only buy back at the 2.81 cents rate - labeled as "Per Exported kWh -
    All kWh Delivered to SRP" in the plan sheet.

    Even with charging from the grid I could not figure out how to make that work. I'd love to see a direct SRP link to the rate plan they are allowing you to use, would be interesting to see.

    The PW has a 10 year limited warranty (Tesla PW warranty link here). I guess it does say unlimited cycles, but that's in the context of that 10 year window. In theory it could last longer depending on how many cycles it's had by that point.
     
    • Like x 1
  11. JayClark

    JayClark Member

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    #11 JayClark, Nov 13, 2019
    Last edited: Nov 13, 2019
    Please let us know how that goes with Tesla. It is interesting, after reading your posts and then crawling the SRP site, I can't find anywhere they mention restrictions on charging from the grid, and in fact in a Q&A about battery systems and the rebate, they seem to indicate if the customer's battery system supports it, then it can be done. At least in terms of "charging" from the grid it says:

    "Battery systems allow customers to store energy from Distributed Energy Resources (DER) such as solar panels, or energy from the grid, for use later"​
     
  12. JayClark

    JayClark Member

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    Scheduling in the app is limited. You can do a weekend, and week day schedules separately. During either of those you can set what they call Peak, and Off-Peak, with a "shoulder" between the two. But they have to be continuous, and I can't find anybody totally satisfied with the behavior of Shoulder periods. They are semi workable for me, but right now I have to manually move the Peak between the current morning/evening peak periods that have a gap of off-peak between to insure the system doesn't hit the grid at some point during peak periods. Twice a day I make the change to move the "Peak" schedule manually from the morning peak, to the evening peak, and then back again. Tesla really needs to enhance this.
     
  13. Vines

    Vines Active Member

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    One way to get the charging to work from the grid is to install the Powerwall without Solar.

    The way I understand it, its technically allowed to charge from the grid, but discharge is not allowed. However its currently not allowed through Tesla if you have Solar. Unsure if this is actually a regulator push back, or Tesla.

    So even with just a Powerwall, it still makes sense to buy cheap power late at night and offset expensive power during the day. Due to the duck curve problem we have here with high PV penetration, and low utilization of night time baseline, I can't imagine the utilities are against this, but I am not really informed or part of that process.
     
  14. Fonzi03

    Fonzi03 Member

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    E-27 Plan can be found here, condition section G shows KW produced are subtracted from KW used.

    https://www.srpnet.com/prices/pdfx/April2015/E-27.pdf
     
  15. Fonzi03

    Fonzi03 Member

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    Precisely why I fought so hard. I absolutely will post an update as things progress.
     
  16. Fonzi03

    Fonzi03 Member

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    Damnit that's horrible. I program Crestron control systems so hopefully I'll run into some time and can dig deep enough to find their API or sniff it out using Wireshark and create I i.agine an SSH connection to the powerwall then I can create any schedule I want in Crestron. If this works out I'd gladly help the community out and could even pre program boxes for people.
     
  17. Fonzi03

    Fonzi03 Member

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    This may double my replies I posted last night but are not showing up now. That's the E-13 plan look at the E-27 plan instead

    https://www.srpnet.com/prices/pdfx/April2015/E-27.pdf
     
  18. bob_p

    bob_p Active Member

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    [QUOTE="The PW has a 10 year limited warranty (Tesla PW warranty link here). I guess it does say unlimited cycles, but that's in the context of that 10 year window. In theory it could last longer depending on how many cycles it's had by that point.[/QUOTE]

    The 10 year unlimited cycles warranty is only valid when the PW is used to store solar energy.

    If the PW is used regularly (not counting Storm Watch charging) for storing grid power, then there is a limit of 38.7 MWh of storage (2800 full 0-100% charging cycles, assuming 1 full charging cycle per day = 7.67 years; for 20-100% charging = 9.6 years).
     
  19. Ampster

    Ampster Active Member

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    I don't think it matters to Tesla if the power company allows charging from the grid. I believe they don't allow it because they want their puchasers to be able to take the ITC without having to keep logs. That is my belief despite what someone from Tesl told you. That leaves people who don't want the ITC out in the cold.
     
  20. jjrandorin

    jjrandorin Another BMW convert

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    Yep... here is the PDF of the warranty, which corroborates what you mention. Charged from solar its 10 years unlimited cycles. Charged from grid it has the limit you mention.
    =====================================

    https://www.tesla.com/sites/default/files/pdfs/powerwall/powerwall_2_ac_warranty_us_1-4.pdf
     

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