Tesla's Low Power Mode: The Science of Long-Term Parking

You’re at the departure gate, about to leave on a two-week trip to Tokyo. You check your Tesla app one last time. Three-quarters full. You feel good.

Three days later, you check again from your hotel room. A quarter of the battery is gone. That is roughly 8% a day, squarely inside the range reported for a car left with Sentry Mode on.

Panic sets in. You run the numbers: at this rate, the car will be empty before you land back in the States. This is the dread of “vampire drain,” also called phantom drain. In August 2025, Tesla shipped a feature aimed squarely at it: Low Power Mode.

It looks like a simple off switch. Underneath, it is a list of things the car stops doing, and knowing the list tells you how long a parked Tesla will last.

This page covers why a Tesla loses charge while parked, what Sentry Mode costs per day, and what Low Power Mode changes. The Tesla documents quoted are the North American Model 3 (2024 and later) Owner’s Manual at software version 2026.32 and Tesla’s US support pages; the Sentry figures from outside Tesla are for Model 3 and Model Y. Other models and older software can differ, and Low Power Mode arrived with software update 2025.32.

The Physics of the Vampire

A Tesla is never fully off. Even parked, the manual says, “its Battery discharges very slowly to power the onboard electronics.” What you leave running decides whether “very slowly” means 1% a day or ten times that.

How much battery does Sentry Mode use per day?

Somewhere between 4% and 14% of the battery per day on a Model 3 or Model Y, and the low end is a projection, not a measurement. The Model 3 Owner’s Manual gives no figure. Its Sentry Mode page says only that “Power consumption may increase when Sentry Mode is active.” The numbers come from outside Tesla, and they describe the feature before and after one software change:

Sentry is expensive because the car cannot sleep with it on. In the manual’s words, “your vehicle’s cameras and sensors (if equipped) remain powered on and ready to record suspicious activity around your vehicle when Model 3 is locked and in Park.” Not a Tesla App reported in November 2024 that this kept both of the car’s computers running, the one behind the touchscreen and the one that handles Autopilot, “causing a 250-watt draw whenever Sentry Mode is on.”

The software change moved motion detection onto the Autopilot computer, so the touchscreen computer can stay asleep until a clip has to be written to the USB drive. Not a Tesla App says Tesla estimated the saving at 40%. It reached the Cybertruck first, in software update 2024.38.4, and the outlet’s source said it would come to other models “in a future update.”

That matters for how you read the bottom row. SentryPro heads its numbers “Confirmed Consumption Data,” but the 4-8% is derived from Tesla’s 40%, not measured: “Based on the 40% efficiency improvement, owners can expect daily battery drain to decrease from the previous 7-14% range to approximately 4-8% daily, though actual results vary by model, battery size, and environmental conditions.” The one test the same article cites, a Model 3 Highland that used 2.7 kWh over 12 hours in June 2025, works out to 225 watts. That is above SentryPro’s own pre-change figure and close to Not a Tesla App’s 250.

The two outlets also differ on who has the change. Not a Tesla App’s follow-up, on November 19, 2024, said the Cybertruck was “the only vehicle to receive these power improvements” so far; SentryPro writes of “other models receiving it in subsequent updates” without naming a version. If you have not watched your own car’s Sentry drain fall, budget for the older rows.

To turn watts into battery percent, multiply by 24 hours and divide by your pack size:

Those are steady-draw figures. Under the redesign, each Sentry event also wakes the touchscreen computer to save the clip.

Does Sentry Mode turn off when the battery gets low?

Yes. Tesla’s support page says: “Unless at a Supercharger, Sentry Mode will remain active until the vehicle is at or below 20% battery. The Tesla app will notify you if Sentry Mode is disabled due to low battery.” The manual ties it to Low Power Mode as well: “If Model 3 enters Low Power Mode, Sentry Mode turns off and the mobile app sends you a notification.” So by default Sentry stops at 20%. The one wrinkle: Low Power Mode’s automatic trigger can be lowered to 10%, and Not a Tesla App’s launch report says that lets you “keep features like Sentry Mode on longer,” while Tesla’s support page states a flat 20%. What remains after Sentry stops is the ordinary parked drain covered below.

How to cut Sentry drain without giving it up

Exclude the places you trust. The manual lists three location exclusions in the Sentry Mode settings, starting with “Exclude Home: Sentry Mode does not automatically enable at the location set as Home in your Favorites list.” Work and your other saved favorites can be excluded the same way. That suits anyone who parks in a safe driveway but doesn’t plug in every night.

The Physics of Heat: “Cabin Overheat Protection”

The second drain is Cabin Overheat Protection (COP). With it on, the manual says, “The air conditioning operates when the cabin temperature exceeds 105° F (40° C), or the selected temperature if available.” There is a lighter setting, “No A/C: Only the fan operates to prevent touch surfaces from getting too hot,” and Tesla is plain that the feature costs charge: “Using Cabin Overheat Protection requires energy from the Battery, which may decrease range.”

Two lines in the same section keep it from being an airport-scale problem. It runs on a timer: “Cabin Overheat Protection operates until 12 hours has elapsed once you exit Model 3, or until the Battery energy drops below the threshold set for Low Power Mode,” whichever comes first. And it is there for you, not for the car: “This feature is intended for passenger comfort and has no impact on the reliability of your vehicle’s components.”

So COP is a cost you pay each time you leave the car in the sun for the day, not one that runs through a two-week trip. Turn it off before a long park anyway. It is one less draw on the pack in the first 12 hours.

Enter Low Power Mode (2025)

Not a Tesla App reported the feature on August 27, 2025, arriving with software update 2025.32, and called it a “vacation mode.”

It does one job: it switches off the features that keep a parked car busy. You can turn it on by hand, or let the car do it when charge runs low. The manual: “You can also choose the percentage between 10% and 20% at which Low Power Mode is enabled automatically. The default is 20%.”

What It Kills

The manual’s list is short: “The following features will be disabled, and are unavailable to enable, when Model 3 is in Low Power Mode.”

1. Sentry Mode
2. Keep Accessory Power On, which matters if you run a cooler or a dashcam from the car’s outlets
3. Actually Smart Summon Standby Mode
4. Keep Climate On and Camp Mode
5. Cabin Overheat Protection
6. Preconditioning

Not a Tesla App’s launch report adds remote seat and steering wheel heating and Max Defrost to that list, and notes two exceptions: “Dog Mode is not included in this list,” and Sentry Mode and accessory power stay on while the car is charging.

On overrides, the two sources disagree. The launch report described a confirmation prompt that let you switch Sentry back on with Low Power Mode active. The current manual says the listed features “are unavailable to enable,” and its Sentry Mode page adds: “If Model 3 enters Low Power Mode, Sentry Mode turns off and the mobile app sends you a notification.” Go by the manual.

What Low Power Mode draws instead

It is not an off switch. The manual: “When in Low Power Mode, Model 3 continues to use energy for standby functions, screen activity, and interactions with the mobile app. In cold weather, available energy may drop more quickly.” Not a Tesla App adds that the car keeps “managing the battery temperature.”

Tesla gives one number for a parked car, and it is the one to plan with: “The Battery can discharge at a rate of approximately 1% per day, though the discharge rate may vary depending on environmental factors (such as cold weather), vehicle configuration, and your selected settings on the touchscreen.” The support site says it another way: “It is expected for a Tesla vehicle to consume around 1% of charge per day while parked.”

Worked backward, 1% a day of a 75 kWh pack is 0.75 kWh, about 31 watts around the clock. On a 60 kWh pack it is 0.6 kWh, about 25 watts.

At 1% a day, a car left at 50% takes about 50 days to reach zero. Tesla’s own worked example: “over a two week period (14 days), the Battery may discharge by approximately 14%.”

The Real Danger: 0% and the Low-Voltage Battery

The number that matters at the bottom is not 20% or 10%. It is zero. The manual: “Discharging the Battery to 0% may result in damage to vehicle components. To protect against a complete discharge, Model 3 enters a low-power consumption mode when the displayed charge level drops to approximately 0%. In this mode, the Battery stops supporting the onboard electronics and auxiliary low voltage battery.”

That last sentence is how a parked Tesla becomes a brick. The roadside section of the manual spells out the consequence: “If Model 3 runs out of range, the low voltage battery is no longer supported – and when low voltage is not supported, the vehicle cannot charge. Therefore, the low voltage battery must be supported by an external power supply to allow you to charge the High Voltage (HV) Battery.” If the car does reach that state, Tesla’s instruction is to “immediately plug in Model 3 to prevent a jump start and low voltage battery replacement.”

Low Power Mode’s 20% default is a different thing: the point where the car stops spending charge on optional features. Not a Tesla App calls it “a reserve battery level.” From 20%, at 1% a day, the car has about 20 more days before zero.

The low-voltage battery can also wear out with a healthy main pack. When it degrades, the touchscreen shows “Schedule service to replace low voltage battery,” and the manual says to have it replaced “at your earliest convenient opportunity.” Do that before a long trip, not after. The 12V battery guide covers the warning signs, and why no alert is not proof of a healthy battery.

The “App Check” Fallacy

One habit undoes much of this: checking the app. The manual is direct about it: “When not in use, Model 3 enters a sleep mode to conserve energy. Reduce the number of times you check your vehicle’s status on the mobile app, as this automatically wakes up your vehicle and starts normal energy consumption.”

If you open the app ten times a day to see whether the battery is draining, you are part of the drain. Apps that poll the car for you do the same job on a timer. Tesla’s range page warns that “third party mobile applications which collect data about your vehicle can decrease range while parked and reduce the battery lifespan.”

Best practice: look every few days, enough to know the car will have charge to reach a charger when you land. SentryPro’s long-parking advice makes the same point: “Monitor your battery level remotely via the Tesla app. Plan to have sufficient charge for driving to a charger upon return.” Just do it sparingly.

Verdict: Do You Need It?

If you charge at home every night, you don’t need Low Power Mode. Use Sentry. Use Cabin Overheat Protection.

If you park for more than a couple of days without a plug, turning on Low Power Mode, or switching off Sentry and COP by hand, is the simplest way to keep parked drain near Tesla’s 1% a day. The checklist below takes about two minutes before you grab your bags.

Leaving Your Tesla Parked at the Airport: The Exact Checklist

1. Leave enough charge, not a full battery. Tesla’s storage advice is to “leave the Battery at around 50% charge and keep it plugged in if possible,” and to “Avoid leaving the Battery at or near 0% or 100% for long periods of time whenever possible.” An airport lot usually means no plug, and for that case the manual says to “keep the 1% in mind to ensure that you leave the Battery with a sufficient charge level.” Count one percent for each day away, add what you need to drive home and reach a charger, then add a margin. For two weeks, 50% to 60% is plenty. For a month, start near 70%.
2. Turn on Low Power Mode. In the car, the manual puts it under Controls > Charging > Low Power Mode; Not a Tesla App says the Tesla app has it under Controls, or as a Quick Action. Before you walk away, check that Sentry Mode shows as off.
3. No Low Power Mode? Switch things off by hand. Tesla’s range page recommends “deactivating features such as preconditioning, Sentry Mode, Keep Climate On, Keep Accessory Power On and any aftermarket equipment when not needed.” Sentry is the big one, reported at 4% to 14% a day on a Model 3 or Model Y, as broken down above.
4. Cabin Overheat Protection off. It stops by itself after 12 hours, but there is no reason to spend that charge cooling an empty car.
5. Unhook the extras. Tesla’s warning covers “Aftermarket equipment connected to the Low-Voltage (LV) system” as well as data-collecting apps. Pause or sign out of trackers for the trip, and take the battery widget off your phone’s home screen.
6. Don’t park in a charging stall unless the lot offers plug-in long-term spaces. A plug is the ideal answer where it is allowed: “Your vehicle is safe to stay plugged in for any length of time.”
7. Check the app sparingly. Every look wakes the car.

How Long Until a Parked Tesla Hits 0%?

Longer than the airport-forum panic suggests, if you did the checklist. At Tesla’s 1% a day, the first row below is simple division. Sentry Mode is what wrecks it.

The first row counts down to zero. The Sentry rows count down to 20%, the default point where Tesla says Sentry shuts itself off, and are rounded down to whole days:

Once Sentry has shut off at 20%, the car is back on the first row, with about 20 days of 1%-a-day drain before zero. Do not plan to arrive there: the 0% protection described above is a last resort, and you still have to drive home.

By trip length, that means:

• 3-day weekend: The car is fine in any setup. Three days of Sentry costs roughly 12% at the low estimate and 42% at the high one, so from a low starting charge Sentry may switch itself off before you are back.
• 1 week: Turn Sentry off. Seven days of it would cost 28% to 56% at the newer estimate and 49% to 98% at the older reports. In practice it runs until the car reaches 20%, then stops.
• 2 weeks: Low Power Mode territory. From 70% you come home to about 56%, which is Tesla’s “approximately 14%” example.
• A month: Low Power Mode on, and mind the start: from 70% you land near 40%, and from 50% you land near 20%.

The Hot-Parking-Lot Factor

Weather moves every number in that table. Tesla’s range page explains why a parked car spends energy on its battery at all: “Even if the vehicle is not being operated, the high voltage battery temperature is monitored and regulated to prolong its lifespan and performance – this is why you may notice the compressor running even while parked.” In a baking lot, expect more than 1% a day. Do not turn Cabin Overheat Protection back on out of sympathy for the interior. The manual says it “has no impact on the reliability of your vehicle’s components.”

Cold raises parked drain too. The Low Power Mode note in the manual says: “In cold weather, available energy may drop more quickly.” What a driving car loses to winter is a separate question with its own answer; the science of EV range in cold weather works through how much of that loss is the cabin heater and how much is the battery.

If you’re sizing up a used car’s battery before a purchase instead, the battery degradation calculator estimates expected capacity by model, age and mileage, and the 2026 Tesla incentives guide covers what’s still on the table if you’re still deciding.

Every watt spent while parked comes out of the pack. Low Power Mode is the software admitting that sometimes the smart thing for a car to do is play dead.

Sources (10)

• notateslaapp.com First Look at Tesla's Low Power Mode (2025.32)
• sentrypro.app Sentry Mode Power Analysis (SentryPro)
• tesla.com Tesla Model 3 Owner's Manual (Sentry Mode)
• tesla.com Tesla Support: Vehicle Safety & Security Features
• notateslaapp.com Tesla Reduces Sentry Mode Power Usage in Update 2024.38
• notateslaapp.com What Tesla Is Changing to Improve Sentry Mode Efficiency
• tesla.com Tesla Model 3 Owner's Manual: Getting Maximum Range (Low Power Mode)
• tesla.com Tesla Model 3 Owner's Manual: Hot Weather Best Practices
• tesla.com Tesla Support: Range Tips
• tesla.com Tesla Model 3 Owner's Manual (PDF, software 2026.32)