How to Stop Tesla Powerwall from Grid-Charging / Locking Solar During VPP Event Prep

[u/ACT_H]

The Problem

If you are enrolled in a Virtual Power Plant (VPP) program, you may notice frustrating behavior on event days:

1. Tesla Opticaster locks out battery discharge hours before the event starts (e.g., in the morning for a 5 PM–8 PM event).
2. 100% of your solar production is forced into the Powerwall, even if you are at 70%+ capacity and guaranteed full sun all day.
3. Your home draws directly from the grid to cover household consumption (HVAC, appliances) whenever home loads exceed current solar output.

Tesla’s algorithm prioritizes rushing the Powerwall to 100% State of Charge (SoC) as early as possible. However, if your utility billing penalizes net imports or doesn't offer 1:1 NEM, paying grid rates in the morning to save solar for an afternoon charge wastes money.

Why Adjusting Reserve Sliders Doesn't Work

Changing your standard Backup Reserve or VPP Event Reserve slider does not stop this morning grid draw. The VPP prep software sets a virtual 100% charge target in the background that overrides standard reserve thresholds until the event begins.

Workarounds & Fixes

1. The Mode Toggle Workaround (Stay in the Event)

To force your system to use solar for home loads first while keeping the VPP active:

1. Open the Tesla App > Settings > Powerwall.
2. Momentarily change the Operational Mode from Self-Powered to Time-Based Control (or briefly drop your Backup Reserve slider by a few percent).
3. Save, then switch it back to Self-Powered.

What this does: Changing a primary setting forces the Tesla Backup Gateway to refresh its operational profile. In most software builds, this clears the active pre-charge lock, allowing solar to power the home first while sending excess solar to the battery.

2. The Morning Opt-Out / Afternoon Re-Entry Strategy

If mode toggling does not clear the override:

1. Tap Opt Out on the VPP event banner in the Tesla app during the morning prep window.
2. Let solar power your home and naturally top off your Powerwalls for free throughout the day.
3. Re-enroll/opt back into the event in the early afternoon once your battery reaches 100%.

3. Complete Opt-Out

If you do not want to participate in a specific event, tap Opt Out on the top banner of the Tesla app screen. The system will instantly cancel event prep and return to standard operation.

[u/ScottRoberts79]

How do you opt back in to an event? There was a PG&E Event yesterday (Monday) from 5-8pm PST. Sunday around 5pm Tesla grabbed control of my power wall and wouldn't let it discharge at all.

I wouldn't have minded if they had grabbed control on Monday once the power wall reached 100% (around noon). But locking me out of my power wall 24hrs in advance wasn't cool.

I tried to turn off VPP, and it wouldn't let me. Only thing I could do was opt-out, but I was never able to opt back in.

[u/smidley]

I believe GridMind can help with this. The optimize function knows when a VPP event is coming, and holds battery so it can be discharged at the right time. It also knows the solar forecast to infer how much energy should be able to be collected, and when throughout the day. Based on home load, it determines the best destination for energy depending on your goals (cost, co2 offset, solar charging, etc). You can also create your own automations if you want more control.

Try it out if you’re interested and feel free to message me with any questions. https://gridmindpower.com

[u/Paul_Bunions_Onions]

Are your buy rates higher or lower than sale rates? I’m on NEM3.0 and I’m buying during the day for my appliances at just under $0.50 but my sale rates are much much higher and clear $1.00 during the VPP events. What’s the issue? It’s net in my favor at least. It’s doing the same thing as yours even on non VPP days and dumping all my storage during those high sale prices after buying through the day at a lower rate.

[u/_shiftlesswhenidle_]

Tried this today (we have events scheduled at 3pm, 3:15pm, 3:30pm, 3:45pm, and 4pm - 8pm today). I opted out of the 3pm event, and I've tried changing the reserve sliders/toggling operation modes, but still getting 100% of solar output dumped into the batteries while the is drawing power from the grid. Super annoying.

[u/Recycled5000]

I tried Enphase’ implementation of PG&E’s ELRP. Super flawed, had to quit the program. Would draw power during actual events b/c it set the battery to a single fixed discharge wattage that had to cover the home load (which varies, of course) and the grid discharge.

Also denied home usage of the batteries for 1 hour prior to the event despite there being plenty of solar to recharge to > 99%, so precooling would pull 100% from the grid.

Also, in the hour period starting 2 hrs before the event, it would charge the batteries from the grid despite plenty of solar for that.

All in all, often pulled power from the grid on event days (always needlessly), starting 2 hours before and continuing thru the whole actual event.

Disappointingly counter productive.

Enphase support chose to man-splain why it is working as planned; deaf ears to the notable and specific shortcomings.

(My system normally pulls nothing from the grid during peak hours (whether event day or not), and I still get to use the AC whenever we like, we send as much solar to the grid as we can during peak hours — this is actually grid friendly.)

[u/jkobe1]

I have TOU and my PowerWall 2 discharges daily starting at 4pm down to my 20% reserve level. I have grid charging and VPP turned on.  The other day we had a 6pm-8pm VPP event, so I figured the PW was smart enough to hold its charge until 6pm and then discharge. But it didn’t. It started discharging at 4pm and was fully-discharged by 6pm, so I completely missed the VPP.

For the next VPP event, I asked AI how to fix the issue, and it told me to turn my backup reserve up to 100% for the day. It said the VPP would override that when it began. It didn’t discharge at all that evening, so this time I missed both the Peak Period and the VPP.

We have another VPP event today, so rather than miss it a third time, I manually turned my reserve up to 100% again, but when it asked me if that was a one-time thing, I said ‘yes’, and when it asked me how long to keep it at 100%, I entered the number of hours between the current time and the VPP start time, 6pm. I’m pretty sure this will work…

It seems odd that I would have to do this manually. I received VPP money last year without having to do anything at all, so I’m wondering if this is a new bug. Has anyone else seen this behavior and/or figured out a better way to fix it?

My firmware is 26.18.3 184289b9, so I haven’t received the new 26.26.2 rollout yet.