Phantom Drain Explained: What’s Normal vs What’s Broken

Few things unsettle Tesla owners more than opening the app and seeing the battery percentage has dropped overnight.
You didn’t drive.
The car didn’t move.
And yet the number is lower than you expected.
This is what’s usually called phantom drain. Some of it is completely normal. Some of it isn’t. The confusion comes from the fact that most advice treats phantom drain as a single issue, when in reality it’s several different systems behaving exactly as designed.
The key is knowing which behaviour is expected — and which deserves attention.
Phantom drain isn’t energy “leaking” out of the battery. It’s energy being used while the car is parked. Teslas don’t shut down in the traditional sense. Instead, they move between different sleep states, and what stays active depends on settings, environment, and how often the car is being woken up.
In other words, most phantom drain is intentional.
In mild conditions, with no special features enabled, a healthy Tesla will typically lose around one to three percent of battery per day while parked. That’s roughly two to six miles, depending on the car. This comes from background systems such as battery management, cellular connectivity, and basic thermal monitoring. Even when the car appears to be asleep, it’s still quietly protecting itself.
If what you’re seeing sits in this range, nothing is wrong.
Where losses start to climb, it’s usually because something is being kept awake.
The single biggest contributor is Sentry Mode. When enabled, the car keeps cameras and processing systems active to monitor its surroundings. Depending on location and activity, Sentry alone can account for five to seven percent per day. This isn’t a fault. It’s simply the cost of turning the car into a security system.
Another common cause is how often the car is being checked. Every time the Tesla app is opened, the car wakes up. Frequent range checks, third-party apps, or background automations can prevent the vehicle from ever entering deep sleep. In these cases, the car isn’t draining because it’s parked. It’s draining because it’s never allowed to rest.
Cabin Overheat Protection is another misunderstood feature. In warm climates, it can consume noticeable energy to keep interior temperatures below set thresholds. Again, this is the system working as intended — but many owners don’t realise it’s active.
Cold weather also plays a role. In low temperatures, the battery may use small amounts of energy to protect itself, even while parked. This behaviour is normal and usually temporary.
Some drain patterns are still normal, but tend to surprise people. Parking in busy areas can increase losses, as Sentry triggers more frequently in response to nearby movement. Park the same car overnight in a quiet garage and the difference can be dramatic.
Software updates can also temporarily increase drain. After certain updates, the car may run background processes or recalibrations for a short period. This usually settles within a day or two without intervention.
What starts to look abnormal is consistent losses above eight to ten percent per day when Sentry is disabled, the app isn’t being checked, and temperatures are moderate. Likewise, if the car never appears to enter a proper sleep state even when untouched, that’s worth investigating.
In many cases, the cause isn’t the car itself but an external app or service repeatedly waking it. True hardware-related phantom drain is rare, but it does happen. Issues such as failing 12-volt systems, sensor faults, or software errors can prevent proper sleep. These cases usually show up clearly in service diagnostics.
The simplest way to diagnose the situation is to remove variables. Park the car for twenty-four hours with Sentry off, Cabin Overheat Protection off, and no app access. Don’t check the car. Let it be.
If drain drops back to a few percent or less, the car is behaving normally and the issue was configuration or usage. If losses remain high, it’s time to look deeper.
Part of the anxiety around phantom drain comes from visibility. Tesla shows you everything. Traditional cars also lose energy while parked — you just don’t get a live percentage update reminding you of it.
Another part is expectation. When a car feels like a piece of consumer technology, we expect phone-like efficiency. But it’s still a two-tonne vehicle managing a large battery in real-world conditions.
Phantom drain isn’t a flaw. It’s a side effect of owning a car that never truly shuts down.
Most of the time, it’s normal.
Sometimes, it’s a settings issue.
Very rarely, it’s a real problem.
Understanding the differenceturns phantom drain from a source of stress into something predictable. And predictability, more than perfection, is what actually makes long-term Tesla ownership feel easy.