What is Tesla phantom drain (vampire drain)?

The basic idea

"Phantom drain" — also called vampire drain — is the charge a Tesla loses while it's just sitting there, parked, doing nothing you asked it to do. You didn't drive it, you didn't precondition it, but you come back a day or two later and the battery percentage is lower than when you left it. That's phantom drain: energy consumed by the car's own background systems rather than by driving.

What's actually consuming the power

A parked Tesla isn't fully "off" the way a gas car with the engine stopped is. Several onboard systems can stay active or wake periodically even while parked:

• Climate-related systems, including cabin overheat protection and, if enabled, scheduled preconditioning — these can draw meaningful power on hot days even with nobody in the car.
• Sentry Mode, which keeps cameras and sensors active to watch for threats near the car — a well-known and fairly significant contributor to overnight drain when it's left on.
• Cellular and network connectivity, keeping the car reachable by the app and periodically checking in, even at rest.
• Battery thermal management, which can kick in briefly to keep the pack within its safe operating range, especially in very hot or very cold weather.
• General computer wake cycles — the car's onboard computers periodically wake from sleep to run checks, sync data, or respond to a phone-app ping, and each wake cycle costs a small amount of energy.

None of this is a malfunction — it's the normal cost of a car that's effectively a always-reachable, camera-equipped computer on wheels. But the total can add up, especially overnight.

Why cold weather makes it worse

Phantom drain is typically higher in cold weather. Battery chemistry is temperature-sensitive, and the car may spend energy on thermal management to protect the pack in freezing conditions — on top of any cabin preconditioning you've scheduled for a warm start. If you've noticed your Tesla seems to lose more charge overnight in winter than in summer, that's a widely reported pattern, not something unique to your car.

Why it's hard to catch by just watching the percentage

The trouble with judging phantom drain from the dashboard is that a single "lost 3% overnight" data point doesn't tell you much by itself — you don't know if that was a one-off (Sentry Mode running near a busy street) or a genuine pattern. Was it Sentry Mode running because you parked somewhere busy? Was it just a cold night? Was it consistent with last week, or a lot worse? Answering that requires comparing multiple idle periods against each other — something the car's own screen isn't built to show you.

Seeing your actual idle periods

This is what Amped's phantom drain tracker is built for: it automatically identifies every period your car sat idle, calculates the drain rate as a percent of charge lost per day for each one, and ranks them so you can immediately see your worst overnight losses instead of guessing. A currently-open idle period shows its running drain rate live, so you don't have to wait for the car to move again to find out something's off.

Seeing the pattern across many idle periods — not just one night — is what turns "my Tesla seems to lose charge for no reason" into an actual answer: whether it's consistent background draw, a Sentry Mode habit, or a cold-weather effect that will ease up once temperatures rise.

Amped tracks phantom drain automatically — it's opening in stages. Join the waitlist and we'll email you the moment your spot is ready, so you can start seeing exactly where your parked charge is going.