Pre-Peak Charge

Adaptive Plan

Pre-Peak Charge replaces “always charge before peak” with a decision. It looks at your typical solar generation, today’s actual cloud cover and your current battery level, then pulls from the grid only when solar won’t get you to your target by peak start.

Why it exists

Tesla’s Time-of-Use mode is supposed to manage this, but most owners end up tweaking their rate plan trying to coerce the right behavior. Grid Getter already has the data (minute-by-minute battery telemetry, hourly solar/load history, weather forecasts), so we can make a real prediction instead of relying on rules of thumb.

What it does

Predicts your remaining solar from now until peak start. Uses your own site’s typical hourly solar profile, scaled by today’s observed clearness (today’s solar so far compared to typical), and optionally adjusted for forecast cloud cover.
Estimates household load for the same window from your own history.
Computes the deficit between your target battery % and what solar will deliver.
Adds two cushions in case the forecast is off. A time margin (15 minutes by default) starts the charge early enough to finish before peak. An energy margin adds 20% to the gap, never less than 0.5 kWh.
Re-decides every 30 minutes (wait, start grid charging, stop, or done), and on every telemetry tick once you’re within two hours of peak, so a late change in the forecast can’t slip through a gap.
Hard deadline. If the deficit can’t be closed in the time left before peak (budgeted at 3.3 kW per Powerwall, the rate Powerwalls actually sustain, plus the few minutes Tesla takes to start a charge), grid charging starts immediately regardless of what the forecast says. The deadline doesn’t override the 1 kWh minimum, though: a gap that small isn’t worth a grid charge even at the last moment, and a battery already at 97% or above is treated as full. It also won’t start a charge in the last few minutes before peak if there isn’t time left to add at least 1 kWh.

How predictions improve

The first two weeks after install, predictions blend a conservative cold-start baseline with your personal history. Once you have ~14 days of telemetry, the model uses your own site’s data exclusively. The weather forecast toggle is optional; with it off, the model still works from your historical curves and today’s observed clearness.

How it’s different from Battery Threshold

Battery Threshold is reactive: drop below X%, charge to Y%. Pre-Peak Charge is predictive: only charge if solar isn’t going to get you there. On a sunny day with a half-empty battery, Pre-Peak Charge waits; Battery Threshold would have pulled from the grid unnecessarily.

You can run both. While a Pre-Peak Charge top-up is running, Battery Threshold waits, so its lower Charge to level can’t cut the top-up short.

Where to find it

Pre-Peak Charge lives on the Background Rules page (Smart Controls → Background Rules), alongside Battery Threshold. That page is the home for automations Grid Getter runs on its own, the ones with no schedule for you to set. Its card shows your Target and, when a later full-by time or measured solar lowers what the top-up aims for, an Aim at peak start row beside it. On track and Short by are measured against that aim, and while a top-up runs the Charge row ends at it.

Pre-Peak Charge is an Adaptive plan feature. Scheduled does not include it — Scheduled subscribers see an upgrade prompt in its place, not a working rule.

Smart Automations adds Pre-Peak Charge to the review screen already ticked whenever you pick a cost goal. Untick it there if you don’t want it. On Scheduled it offers Charge before peak instead: a Battery Protection rule that charges from the grid for the 2 hours before each peak rule starts, with no solar forecast.

You’ll also see it in a few places while you work:

An announcement banner on the Automations page, until you set it up or dismiss it.
A suggestion while you create a Peak Time or DemandGuard automation. That automation raises your reserve; Pre-Peak Charge makes sure there’s charge to raise it to, so the two are offered together. Added this way, it charges to the same reserve the paired automation holds. Because that shortcut can’t take a “Battery full by” time, a “Pre-Peak Charge is on” note follows the save: Continue to set it up opens the rule’s settings, Not now leaves it filling by peak start until you visit Background Rules.
A lead-in on Today’s Automations, fused to the left edge of the peak window it serves and marked if needed, since it only charges on the days the forecast falls short. Its time reads by that window’s peak start, or the later “Battery full by” time you set for it.

When it charges

Pre-Peak Charge needs an active DemandGuard or Peak Time automation on your site. It exists to fill the battery before that automation’s peak window opens. No such automation, and Pre-Peak Charge does nothing: no forecast, no charge, no notification.

On a day the forecast says solar won’t get you to your target by itself, Pre-Peak Charge starts charging from the grid, a few minutes before the latest moment a charge could still reach the target (the latest safe start). Waiting until then means the forecast only has to be right over the charge itself, not over hours of solar that might still fill the battery anyway. It always stops by the time the peak window opens, or earlier if solar catches up and tops the battery off first. An early stop isn’t the end of the day’s watch: it keeps checking until peak, and if clouds roll in and the forecast slips back into deficit it starts charging again, with another notification.

The forecast compares today against your home’s typical pattern in two ways: how much solar you’ve produced so far versus a typical day, and how much your home has drawn over the last few hours versus a typical day. A cooler day where the air conditioning barely runs lowers the expected draw before peak, so the forecast doesn’t plan a top-up for load that isn’t happening.

When it starts, you get a “Pre-Peak Charge started” notification telling you how far short the battery was heading and how much it’s pulling from the grid to close the gap. It carries a Cancel button: tap it to stop the charge immediately and put the battery back to its normal settings. Canceling also skips the rest of that day; the automation evaluates again tomorrow. A second “Pre-Peak Charge canceled” notification confirms the charge actually stopped, however you canceled it.

Charging is never held back just to make sure a Cancel button can go out. If a charge starts in the last half hour before your peak window, you still get charged and still get notified, just without a Cancel button on that notification (and none in the notification center either, since it’s the same notification). You can still cancel from Cancel charge on the Live Dashboard card.

iPhone/Android: Cancel appears as a button on the notification once your app has updated to support it. Until then, cancel from the Grid Getter website instead: sign in on any browser and use Cancel charge on the Live Dashboard card, or Cancel on the notification in the website’s notification center. Either does the same thing. You can also cancel from the Pre-Peak Charge card on the app’s Live Dashboard.
Web: Cancel also works from the notification center.

Before the top-up

On a day the forecast calls for a grid top-up, the battery can drift down while it waits for the charge to start. If the house is running on it all morning, the top-up then has more to make up. So once Pre-Peak Charge has seen how much sun the day is actually getting (homes without solar skip that wait) and still expects to need more than 1 kWh from the grid, it holds the battery where it is.

To do that, it sets the reserve just under the battery’s current level, in Self-Powered mode with grid charging off. The battery gives up a percent or two once, then sits. Meanwhile the house runs on off-peak grid power. If the sun comes out and solar charges the battery, the hold follows the level up. It doesn’t start when the battery is above 80%, since there’s little for a top-up to add at that point.

While it’s holding, the Pre-Peak card on the website’s Live Dashboard shows Holding the battery at 62% until the grid top-up. under the status line, or …until peak. once no top-up is planned. The iPhone and Android apps show the same line on their Pre-Peak card. There’s no notification for the hold.

The Activity Log gets a Pre-Peak Charge row when the hold starts, such as Holding the battery at 62%: the forecast needs a grid top-up before 5:00 PM, so the house runs on off-peak grid until then. When the hold lets go you get a second row that starts with Released the battery hold: and gives the reason. The one exception is when the top-up starts. The hold hands over to the top-up without a release row, and the top-up logs its own start.

The hold lets go when:

solar is now forecast to cover the gap,
the battery climbs past 80%,
a grid program event (such as a VPP dispatch) takes over,
Battery Protection acts,
you skip the day,
you turn Pre-Peak Charge off or your plan no longer includes it, or
peak is 15 minutes away.

The first four only pause it; if a gap still needs filling, the hold can start again 15 minutes later. The last three end it until the next peak window.

When the top-up begins, it takes over from the hold. When Battery Protection sets the reserve itself, the hold hands the battery to it and changes nothing more. Otherwise, when the hold lets go, or after the top-up, your reserve, operation mode and grid-charging setting go back to what they were before the hold, including a grid-charging setting you had turned off.

On the Live Dashboard

When Pre-Peak Charge is set up, a card appears under Power Flow on the Live Dashboard explaining what’s happening today. It’s on the Grid Getter website and in the iPhone and Android apps. The badge in its top corner names today’s state:

On track — solar gets the battery to your target on its own, or close enough: whatever is left is under 1 kWh, too small to be worth a grid charge.
Top-up planned — solar won’t cover the gap before peak, so a grid top-up will start by itself later; the card says roughly when.
Charging from grid — a top-up is running right now.
Latest safe start — a top-up is running and the forecast leaves little slack before peak; the card shows how long the rest of the charge takes.
Topped up · stopped — a running charge already reached target and stopped, ahead of peak. It starts again if the forecast slips before peak.
Ready for peak — however today played out, the battery reaches target by peak start.
Canceled today — you canceled today’s charge; the automation resumes tomorrow.

The projection bar

The bar shows how full the battery will be at peak start, with a Target N% marker at your target. When a later “Battery full by” time or this peak’s measured solar lowers the aim, the marker sits at that lower aim instead and reads, for example, Aim 91% · full by 4:30 PM (just Aim 91% without a later full-by time), and everything on the card (the shortfall, the headline figure, the sentence under the tiles) is measured against it. The legend under it names each part. Battery levels show both the percentage and the energy it represents, for example Now 79% · 21.3 kWh:

Now X% — the battery right now.
Before top-up X% — replaces Now when the reading was taken mid-charge. That reading already includes the grid energy added so far, so the bar shows the charge from before the top-up and stacks the grid share on top of it, instead of counting that energy twice.
At h:mm X% — replaces Now once a peak has started: the battery at the last check before it.
Grid top-up X kWh of Y kWh — grid energy added so far, out of the gap being covered.
Net solar to come +X kWh — the solar expected before peak that’s left over after your home’s use, since that’s what reaches the battery. It shrinks through the day as both the remaining sun and the remaining use run down; the gross forecast is on the Solar until peak tile below.
Short of target X% · Y kWh — how far below target the battery ends up without more charging (Short of aim when the aim is lower than your target). The kWh here is the plain shortfall; the Gap to cover tile adds the safety cushion on top, so it reads a little higher.

At the right end, the headline figure is the predicted battery level at peak start, in percent and kWh. It’s labeled Without more charging when the battery is heading at least 1% short of target, and At peak start otherwise.

Figures

Below the bar, tiles show the numbers behind the plan:

Solar until peak — the solar expected between now and peak start. Sites with no solar don’t get this tile.
Home use until peak — what your home is expected to use over the same stretch.
Gap to cover — the energy the battery will still be missing at peak start, cushion included. It reads None when there’s no gap. A gap under 1 kWh carries the note Below the 1.0 kWh start threshold, because Pre-Peak Charge doesn’t start a grid charge that small. When a grid top-up is involved, the tile spells it out in one line:
- Planned: About 25 min from the grid, starting around 1:11 PM, done before 1:59 PM. The plan is re-checked as the day goes on, so the start can move or the top-up can be dropped.
- Charging: Charging since 1:21 PM. Stops at 91% or at 1:59 PM, whichever comes first. The percentage is the level the top-up aims for, which is lower than your target when a later Battery full by time or this peak’s measured solar lowers it.
- Stopped early: 1.6 kWh from the grid, 1:21–1:46 PM.

Every tile, and every row in the forecast detail, has an info icon. Hover over it, or tab to it with the keyboard, to see what the figure means and how it moves the plan.

During peak · last 30 days

Once a peak window has about a week of measured data, an amber row under the tiles tells you what solar did during that window on its peak days over the last 30 days (days your peak rules skip, such as weekends, aren’t counted), for example Solar usually covers your home until about 5 PM and adds 2–9 kWh your battery could absorb if it had room. The hour is when solar typically stops covering the house; the range is the energy the house didn’t use, from a poor day to a good one. Starting peak with a full battery means that solar exports instead, so the row offers Set a later full-by time (see Settings). When solar rarely exceeds what the house uses, or a poor day’s surplus is too small to lower the aim by any time in the window, the row says so and offers nothing — a lower target wouldn’t help.

With a later “Battery full by” set, the row reads Aiming for 91% at 2:00 PM; solar finishes the fill by 4:30 PM. If the time you chose is too early for a poor day’s solar to lower the aim, the row says so instead and the grid still fills to your target at peak start. Pre-Peak Charge never charges from the grid inside a peak window; the later time only lowers what the grid top-up aims for at peak start. The card’s aim, gap and planned top-up (its minutes and start time) reflect a change to the rule as soon as you save it; the decision to charge is made at the next evaluation.

Buttons

Cancel charge stops a running top-up immediately and restores your battery’s normal settings (reserve, operation mode and grid charging, including grid charging you had turned off), the same as the Cancel button on the notification. It’s only active while a top-up is running. Once peak starts it stays on the card but can’t be pressed.

In the iPhone and Android apps, the card also has Skip today before anything has run, and Undo skip after you skip. Skip during a peak and the card switches to the upcoming peak, so you can see the skip and undo it.

Forecast detail expands the card into the full forecast, and Hide forecast detail collapses it again:

Row	What it shows
Predicted at peak	The battery level expected at peak start, in percent and kWh
Target	Your target battery level, in percent and kWh
Full by	Peak start, or the later time you chose for this window
Effective target	Shown only when the aim is lower than your target (a later full-by time, or this peak’s measured solar): the level the grid top-up actually aims for at peak start
Gap incl. safety margin	The energy still missing, cushion included
Safety margin	The time margin and energy cushion, for example 15 min · 20% of gap
Forecast	Weather · N% cloud cover when the local weather forecast is on, Off · site history only when it’s off
Clearness today	Today’s sunshine against a typical day for your panels, for example 1.00×. A dash means there isn’t enough data yet
Site history	How many days of your own data the forecast uses, for example 9 days
Next evaluation	When the forecast runs again, or Soon. Once a peak has started it reads Before next peak

Sites with no solar skip the solar figures; the card explains the charge purely by time to peak.

During and after peak

Pre-Peak Charge stops checking once your peak window opens, but the card stays put:

Peak under way — during the peak window, the card shows what the last check before peak saw: the battery level then, what it expected at peak start, and any grid top-up it added. The line under the title reads Peak started X · last reading Y. Below that, the card says what the battery actually measured at peak start, and at your Battery full by time once that has passed, for example: At peak start the battery was at 94%, and at 4:30 PM it was at 86%. The large figure shows the measured level at peak start, not the forecast. On the web for now; the apps still show the last check.
Peak done — after the window ends, the card keeps that same reading until the first check for your next peak, which usually runs in the early morning. The line under the title reads Next peak X · last reading Y, and the card ends with Checks resume before the next peak at X.

A few lines replace the reading when it doesn’t apply:

You skipped Pre-Peak Charge for this peak.
No reading was taken before it.
You canceled the top-up after X kWh.

Before the first check

Waiting for first check means Pre-Peak Charge is set up but has no reading to show yet, for example right after you turn it on. The card names your next peak and fills in once the first check runs. If no peak is coming up, the line under the title reads No peak in the next week.

If a peak starts before Pre-Peak Charge ever got a reading, the badge reads Peak under way and the card says so: Peak is under way, and Pre-Peak Charge didn’t get a reading before it started. It checks again before the next peak at X.

In Display Mode, the Pre-Peak panel only shows what’s coming next, so it stays hidden during and after peak.

Settings

Setting	Default	Notes
Target battery %	100%	Slider, 50–100% in 5% steps — how full you want the battery at peak start. When Pre-Peak Charge is added alongside a Peak Time or DemandGuard automation, it starts at that automation’s peak reserve instead.
Use local weather forecast	On	Adjusts the solar prediction for today’s forecast cloud cover; with it off, the model relies on your historical curves and today’s observed clearness
Battery full by	Peak start, per window	One row per peak window from your Peak Time and DemandGuard rules (a summer afternoon and the two winter windows on an SRP plan, say). Choose a time inside the window, in half-hour steps, and the grid top-up aims lower at peak start by the solar that window has typically added by then on a poor day over the last 30 days; solar during peak finishes the fill. Grid Getter ends the top-up itself when the battery reaches the lower aim, so any aim between 50% and your target works. When a poor day’s solar adds too little by your chosen time to lower the aim, the row says so and the aim stays at your target. On a cloudy day the battery may start peak below your target, and with DemandGuard on that window peak start is the safer choice. When the window’s DemandGuard still uses the Classic hold, the row warns that Tesla can spend this charge during peak and links to that rule to switch it to Advanced. Pre-Peak Charge never charges from the grid inside a peak window.

Pre-Peak Charge runs automatically before your peak window, and its schedule comes from your rate plan rather than a separate days/months picker. There’s nothing to configure beyond the settings above.

A site has one Pre-Peak Charge rule. Turning on a second one while the first is active fails with Pre-Peak Charge is already set up for this site; edit the existing rule instead. The same applies when re-enabling a disabled copy while another is on.

If you later move a peak window’s start, a full-by set for the old window no longer applies: the rule falls back to peak start for that window and the Background Rules card, the Automations page and the save confirmation all ask whether to keep the time or leave it at peak start.

On a plan with two peak windows a day (for example a morning and an evening peak), Pre-Peak Charge runs once before each window. Each window gets its own forecast, its own charge and its own restore when that window opens. Canceling applies to the whole day — both windows.