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I stand corrected - I did not see a voltage tap connected to panel in my installation, but must have missed it.

"CT" in the sense of how the term is used here generally refers to "current transformer," not "current transducer". This means that it actually measures both voltage and current. The Neurio inside my Tesla Gateway reports both voltage and current from each CT (as well as other stats like frequency).

The export limit only really matters if you're on a VPP or have "export everything" available. Do you have either of these? Without these features, the export to grid is limited by what the solar panels produce and in most US locations the systems are sized so the full solar export is allowed (I...

Nope. As you can see, at worst there were 7 extra discharges in a year through this VPP program. In fact, since I'm on TOU with export everything, they aren't even extra discharges, just time shifts of when the discharge occurs.

37.8 MWh is about 2800 full discharges of the battery. Even discharging the full battery every day it would take abut 7 years and 8 months to hit this limit. As long as the VPP doesn't involve full discharges 365 days a year and your reserve is set to 0%, I don't think a VPP is going to be an...

Generally the Powerwalls are registered, installed and connected to the internet before PTO (permission to operate). They just are configured not to export to the grid until then. It may be worth double-checking with your installers that they are going to do this.

Hour-by-hour is the way it used to work a few years ago when I was a member of OhmConnect. I think it likely that they haven't changed. The 10 weekday and 4 weekend day lookback periods are the same as back then, for example. It should be easy for me to tell at the end of this season if we keep...

Here's an example: https://www.cpuc.ca.gov/-/media/cpuc-website/divisions/news-and-outreach/documents/news-office/key-issues/summer-reliability/copy-of-proposed-decision-in-r2011003-attachment-2-with-track-changes.pdf

You are reading this correctly, but the detail is that it is on an hour-by-hour basis, not over the whole period. You can set your reserve to 100% for the first hours of the VPP event and then set it back down when you usually stop exporting.

No, @Redhill_qik is correct. Tesla applied for "sub-metering" for the ELRP program, which means it's what the Powerwall discharges that matter, not the export to the grid. See section A.4 here...

AFAIK, the baseline is computed on an hour-by-hour basis, so if you normally export earlier, your baseline could be 0.

FYI, the VPP works in a similar way. The compensation is still based on how much you exported compared to a typical day (see here: Emergency Load Reduction Pilot | Tesla Support). The biggest difference is that it is based purely on Powerwall charge/discharge. Usage from the grid is ignored.

Call Tesla support. It may be something like the time zone on your gateway being set wrong so it's generating the wrong time stamps. In any case I suspect it's an issue that can be fixed in the configuration of your system. Something probably went wrong during provisioning.

Historical note: the original app did not do this adjustment. The 5% adjustment was added to the app later when they decided the built-in buffer wasn't enough. The app shows 0 when the battery is actually at 5. It shows 100 when the battery is at 100 . The adjustment is just applied linearly in...

For the California VPP, being enrolled in any other demand-reduction or similar incentive program disqualifies you. I don't know of an exhaustive list, but it does include programs like OhmConnect, smart thermostat programs like SmartAC, etc. Note that taking rebates is fine. I think they're...

I think day-to-day production differences due to temperature and wind will dominate the change from the angle. I saw a 10% difference between Sunday (high of 88) and yesterday (high of 74).

When I got my Powerwalls a few years ago, PG&E dropped me from my CCA without my requesting it. Beware: going back on the CCA triggers a true-up (and changes your true-up month). They billed me more than $500 that I would have been able to make back in the summer when I went back on the CCA.

10 kW is the cut-off that PG&E uses to distinguish between "small" and "large" systems. The interconnection agreement is different depending on this classification. As far as I know, this only affects grid charging.

Here is ChatGPT's explanation of the post: IRS and AHJ: The IRS refers to the Internal Revenue Service, the U.S. government agency responsible for collecting taxes and administering the Internal Revenue Code. AHJ stands for "Authority Having Jurisdiction," which in the context of electrical...

I'm not sure what OP is looking for, but this is the net export, not the total export. In some cases it's interesting to know the actual total exported to the grid in the month, rather than total exported minus total imported.

Totally understood. I'm just saying that there also is no point in trying to run without disconnecting from the grid because it likely won't work due to the draw from the grid. I'm assuming that that this would kill a generator too. My curiosity is not why they require disconnection, but why the...

I don't think Forbes is a reliable reference for this. On energy.gov (Homeowner’s Guide to the Federal Tax Credit for Solar Photovoltaics) there is this FAQ: My reading of this is that you get the credit on any project as long as it meets the requirements of the program. Whether a portable...

You can see individual battery charges using the local API by requesting https://<powerwall ip address>/api/system_status. You get something like the following: { "command_source": "Configuration", "battery_target_power": -2364.7474316420776, "battery_target_reactive_power": 0...

I've always found it curious that this is the justification is used. It seems to me like there's a second, more important reason you can't feed power to the grid when the grid is out: the grid is a load that's much larger than the PV system can handle. If the system tried to connect to the grid...

Electricity can flow both directions in wires. The only time the location of your loads matters is when the power is out and the gateway has disconnected from the grid. If the loads are on the grid side of the gateway, they can't be powered by solar/Powerwalls during a grid outage. When the grid...

Are you sure this won't work with a non-Tesla EVSE? If it's controlled by a frequency shift, wouldn't the car still be able to detect it?

California VPP payouts are more like $100 per Powerwall. The four figure payouts are for the Northeastern VPP programs where they take over your Powerwalls for an unspecified number of events (you can't control your reserve) and then pay out at the end of the year based on your average...

I’m not an expert, but the lowering is by a small amount so I’m guessing most non-Tesla equipment would ignore it. They have to lower rather than raise because otherwise the car wouldn’t charge when the gateway is curtailing solar. I assume the limit for the reserve setting is 90% so it can’t...

To add evidence to this, when you query the API, the following values are visible for the operation mode: { "real_mode": "autonomous", "backup_reserve_percent": 33.5, "freq_shift_load_shed_soe": 90, "freq_shift_load_shed_delta_f": -0.32 } The "freq_shift_load_shed_soe" changes when you change...

True. What I’m saying is I have observed one of my Powerwalls hit 100% before the other. The other kept charging for a minute or so after the first stopped charging.

My two Powerwalls discharge in parallel. I think the only time there might be a significant imbalance is if they reach fully charged (when charging) or the backup reserve (when discharging) at different times.

PG&E takes the most advantageous (for them) interpretation: they remove the excess export credits from highest rate period first. I ran into this once when PG&E double-billed me by accident.

For historical context, the Tesla algorithm used to only charge the Powerwalls if it saw a need to discharge later in the same day. Creating a fake peak period was the workaround to this behavior. It has been a long time since I was on a rate plan with off-peak weekends, so it's quite likely the...

Are you sure? My understanding is that the Neurio uses a current transformer to get an AC input signal to the main unit that is then measured there (possibly with a built in transducer). The parts are described as "current transformers" in the catalogs: Neurio SEK-2U Universal Current...

I don't think that your argument is likely to succeed. As I understand it, the CEC-AC rating is just a nominal size for your system. In reality, your system can push as high as your nameplate rating through the transformer. I have a 6.3 kW DC system with a 7.6 kW inverter and have seen...

That's correct. The way my CTs are configured is that they're on solar and site (grid). The house load is calculated from the CT measurements plus the Powerwall output. If a CT is placed on the wrong line or reversed, the house load will look strange because it is calculated from the other...

In theory that's what it does now. It's using solar forecasts, which should account for weather. It still does seem to optimize for self-consuming solar rather than storing it in the battery, though. As a result, my Powerwalls often seem to fill up before the afternoon shoulder/peak period...

They probably don't require power to your house, but they do require power to their networking equipment in your neighborhood. This equipment probably is affected by the same power outage. Supposedly optical fiber service is generally less susceptibly to these failures since a larger part of the...

I believe that if both of your solar systems are fed into the gateway the ZigBee boxes should no longer be needed. My understanding is the ZigBee boxes were originally used to send the inverter data to Tesla to monitor solar generation. I have a third-party-installed solar system hooked to a...

I think it may be worth taking a step back. Prior to the IRA, the statute for the ITC only said renewable energy systems were eligible for the credit. So the question was whether a battery was part of the renewable energy system if it was installed after the solar system. The Private Letter...

This only applies to commercial installations, not residential. For residential, the reference is an IRS letter that says that in their opinion the law intended only to allow batteries 100% charged from solar. There is no mention of an ITC claw-back for residential projects either, so it's...

FWIW, according to the release notes Tesla added the consideration of solar forecasts to the charging behavior in version 22.26 (released September 2022). Here in the US, it does seem to work. My Powerwalls charged to nearly full overnight the past two days when it was raining. The forecast for...

Based on data returned by the API, the current EV charging setting seems to do the charging control using frequency shifting. Obviously this can only happen when the grid is down, so they'll have to come up with a new way of communicating for this feature. The frequency shift is clever, since...

The production cap is even a little worse than it sounds. Not only are you disallowed the overage, but if you're on a TOU plan, PG&E subtracts the excess export from the highest rate first, even if the excess happened during a lower rate period. This means you really don't want to run into this...

In theory, solar should shut off when the PW is full and the grid is down - the Powerwalls shift frequency to shut the solar down. If you actually had 3.6kW with nowhere to go, you'd probably notice the smoke...

The Wh numbers the API returns for pack energy and current charge do not reflect this. My personal guess is they minimize charging at a high SOC to avoid battery degradation. Doesn't backup-only do something similar? I seem to remember that it also would let the charge float down to 97% before...

min_site_meter_power_kW is the export limit. The Powerwalls will limit exports to stay under this total export number for the site. Presumably max_site_meter_power would be the import limit, and the Powerwalls would attempt to keep the site imports less than that amount. nominal_system_power_kW...

My site was limited to 8kW when I first checked some time back. When they enabled export everything, the limit was removed so I could export at 10kW. They added the export limit back at 7.8kW when I signed up for the VPP a little later. The timing could be coincidence, though.

I miss the Tesla loss-leader days when they charged me $900 to install two Powerwalls and tie them to an existing solar system.

There was a period where Tesla used SolarEdge inverters. See other threads on this board about people's troubles with them. I think Tesla no longer uses SolarEdge inverters, so current installs should be much less likely to have this problem.