Battery Threshold

Free Scheduled Adaptive

Battery Threshold watches your battery level and charges from the grid when it drops too low — automatically, during the time windows you choose. Set a floor and a target, and Grid Getter handles the rest.

You’ll find your rules on the Background Rules page (Smart Controls → Background Rules) — the home for the automations Grid Getter runs on its own, with no schedule for you to set. Battery Threshold shares that page with Pre-Peak Charge.

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What it does

• Monitors battery level in real time. Grid Getter checks your battery percentage every minute via Tesla telemetry.
• Charges when needed. If your battery falls below your threshold, Grid Getter switches your Powerwall to Autonomous mode and sets a battery reserve equal to your charge target. Tesla draws from the grid to reach that level.
• Backs off automatically. Once your battery hits the target, Grid Getter returns your Powerwall to Self Consumption mode — so it stops pulling from the grid once the job is done.
• Stays charged (optional). Enable Hold Charge to keep your battery at the target level for the rest of the window. Grid Getter switches to Self Consumption, disables grid charging and leaves the reserve pinned at your target — so the battery won’t drain below it, and won’t keep pulling from the grid above it. Solar still powers your home first; any surplus tops the battery up for free. Useful when you want to guarantee a minimum charge through a specific window. The reserve never goes above the battery’s current level: when the battery is right at the target, it’s pinned a point or two under it, because a reserve above the battery makes your Powerwall charge from the grid even with grid charging off.
• Resets at window end. When the active time window closes, your Powerwall returns to your resting mode regardless of battery state — or to Self Consumption if you haven’t chosen one.

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How Grid Getter charges your battery

Battery Threshold doesn’t run on a timer — it reacts to your actual battery level.

Every minute, when telemetry from Tesla arrives, Grid Getter evaluates your battery state against your settings:

Battery state	What happens
Below Threshold %	Switch to Autonomous mode, set reserve to Charge To % — grid charging begins
Between Threshold and Charge To %	No action — charging is already in progress
At or above Charge To %	Return to Self Consumption and reset the reserve — or, with Hold Charge on, stay in Self Consumption with grid charging off and the reserve held at Charge To %
Window ends	Return to your resting mode with grid charging set back to how it was before the window (allowed, if Grid Getter couldn’t read it then) — or, with no resting mode set, Self Consumption with grid charging off. If a DemandGuard window starts as this one ends, DemandGuard sets the mode and reserve instead, and Battery Threshold only lowers a reserve it raised itself if DemandGuard hasn’t set one within a few minutes

Setting a battery reserve in Autonomous mode tells your Powerwall to treat everything below the reserve as off-limits for home discharge — so Tesla charges up to that level from the grid. Autonomous mode will keep charging past the reserve when it decides grid power is cheap, which is why Grid Getter leaves it as soon as the target is reached: with Hold Charge on, the reserve becomes a floor the battery sits on, not a level it climbs past.

Charging you didn't schedule?

If your resting mode is Time-Based Control, the window-end hand-back puts Tesla’s own optimizer in charge. Tesla may then charge from the grid ahead of your peak hours on its own schedule — the Tesla app shows it the same way, but no Grid Getter rule is running. Rules you’ve switched off never run; you can confirm what fired in the Activity Log, which records every charge, hold and window-end action Grid Getter takes.

Tip

Battery Threshold runs via Grid Getter’s live telemetry stream, not a scheduled cron job. There’s no delay between your battery falling below the threshold and Grid Getter acting — the check happens on every telemetry update.

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When to use it

Pre-charge before a peak window. If you have a Peak Time automation that holds your reserve at 30% during evening hours, use Battery Threshold during the day (say, 8 AM–2 PM) to ensure your battery is fully topped off before peak starts.

Protect against overnight depletion. Set a threshold of 15% with a 7 AM–9 AM window. If your battery ran low overnight, Grid Getter charges it each morning before you start drawing power.

Guarantee a storm reserve. Before severe weather season, set a high threshold window during off-peak hours so your battery stays charged without having to think about it.

Note

Battery Threshold defers during active DemandGuard intervals. If DemandGuard is running a demand check at the same minute, Battery Threshold skips that cycle and resumes on the next one.

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Creating a Battery Threshold automation

1. Go to Automations and find the Smart Management section at the bottom of the page

2. Click + Add

3. Give your automation a name (e.g., “Morning Pre-charge”)

4. Set your Threshold — the battery percentage that triggers charging (default: 20%)

5. Set Charge To — the target battery percentage to charge up to (default: 50%)

6. Optionally enable Hold Charge to keep the reserve at the target level for the rest of the window instead of resetting it

7. Set your Active Times — one or more time windows during which this automation can run (default: 7:00 AM–3:00 PM)

8. Adjust Days of Week and Months to match your schedule

9. Click Create Automation

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Schedule modes

When setting Active Times, you can choose how the schedule is determined:

• Custom window — you pick specific time windows when the automation is allowed to run. You can add multiple windows (Scheduled).
• Outside Peak Time and DemandGuard windows — Battery Threshold automatically runs during any time not covered by your active Peak Time or DemandGuard automations. This is the recommended mode if you already have those automations set up — Battery Threshold fills the gaps without overlapping them.

It also stays out of the windows of your other turned-on custom window Battery Protection rules, such as the Charge before peak rule that Smart Automations creates on Scheduled. While one of those rules is inside its window, the derived rule leaves your Powerwall’s mode and reserve alone, including at the end of its own window, so the two rules never act at the same time. If you only have one Battery Protection rule, nothing changes.

Tip

If you select Outside Peak Time and DemandGuard windows, you don’t need to manually manage your Battery Threshold schedule when you add or change Peak Time or DemandGuard automations. The schedule updates automatically.

Overlap warning

If you set a custom window that overlaps an active Peak Time automation, Grid Getter shows a non-blocking warning: “This window overlaps with [automation name]. Battery Protection will defer during that time.”

This is informational. Battery Threshold still saves and runs, but it won’t charge during the overlapping period. Battery Threshold defers only while a Peak Time rule is turned on and inside its window. A rule that’s turned off doesn’t hold Battery Threshold back.

A custom window can’t overlap a turned-on DemandGuard window at all, because DemandGuard manages your battery reserve for its whole window. The form shows why and won’t save until you move the window or switch to Outside Peak Time and DemandGuard windows. A window that ends exactly when DemandGuard starts is fine. This includes a 24-hour DemandGuard, which leaves no room for a custom window, so use Outside Peak Time and DemandGuard windows there.

Battery Threshold also steps aside while a Pre-Peak Charge top-up is running. It won’t start its own charge, and it won’t stop Pre-Peak Charge’s top-up when the battery reaches your Charge to level. It picks up again once that top-up stops.

When you stop DemandGuard mid-window

In Outside Peak Time and DemandGuard windows mode, only active rules’ windows are excluded from your schedule. If you stop or disable a DemandGuard rule while its window is open, including with Switch & Stop on the Live Dashboard, that time is free again. Battery Protection can then charge from the grid during it, on peak, as soon as your battery drops below your threshold.

After Switch & Stop, Grid Getter asks what you want to do in a Battery Protection Will Take Over dialog. It names your rule, shows your threshold, target and current charge, and reminds you that grid draw during peak hours counts toward your demand charge.

• Pause Battery Protection turns the rule off until you switch it back on from the Automations page.
• Keep it running leaves the rule on, and it can charge during the rest of the window.

Whenever you turn off a Peak Time or DemandGuard rule while a Battery Protection rule in this mode is on, from any screen or app, Grid Getter also sends a push: Battery Protection now running in this window. It names the rule you turned off and the Battery Protection rule that now runs in its place.

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Settings reference

Setting	What it does	Default
Name	Label for this automation	Battery Threshold
Description	Optional note	Empty
Threshold	Battery % below which charging triggers	20%
Charge To	Target battery % to reach	50%
Hold Charge	Keep the reserve at target (grid charging off) instead of resetting it once charged	Off
Schedule Mode	Custom windows or derived from other automations	Custom
Active Times	Time windows when the automation can trigger (custom mode only)	7:00 AM–3:00 PM
Days of Week	Which days the automation is active	Mon–Fri
Months	Which months the automation is active	All

Caution

Threshold must be lower than Charge To. If they’re equal or reversed, the automation won’t save.

Note

Charge To sets a backup reserve while charging, so it snaps to 80% if you pick a value between 81% and 99% — Tesla’s cloud API won’t honor that range. Threshold caps at 80% for the same reason. Set Charge To to 100% for a full charge-and-hold. See Why can’t I set a battery reserve between 81% and 99%?

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Example configurations

Pre-charge before peak hours

• Threshold: 25%
• Charge To: 80%
• Hold Charge: off
• Active Times: 6:00 AM – 2:00 PM
• Days: Mon–Fri

If your evening peak window starts at 4 PM and your battery tends to drift low during the day, this keeps it topped up during cheap off-peak hours so it’s ready when peak arrives.

Overnight minimum battery floor

• Threshold: 10%
• Charge To: 40%
• Hold Charge: off
• Active Times: 6:00 AM – 9:00 AM
• Days: Every day

A short morning window that catches any overnight depletion. If the battery is already above 10%, nothing happens.

Weekend storm reserve

• Threshold: 50%
• Charge To: 90%
• Hold Charge: on
• Active Times: 8:00 AM – 6:00 PM
• Days: Sat, Sun
• Months: Jun, Jul, Aug, Sep

Keeps the battery well-charged on weekends during summer storm season. Hold Charge keeps it at 90% through the window rather than letting it drift.

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Plan requirements

The free plan includes one Battery Threshold rule with basic settings. Unlimited rules and every setting are available on Scheduled plans or higher.

Some settings are restricted on the free plan:

• Hold Charge — available on Scheduled plans or higher
• Multiple active time windows — available on Scheduled plans or higher
• Custom days of week and months — available on Scheduled plans or higher

If you move to the free plan, your existing rule keeps running with default schedule settings. See Subscription Tiers for upgrade options.