What Sentry Mode actually costs: breaking down idle drain
"Sentry costs a few percent a day" — and every owner quotes a different number, because everyone parks somewhere different. Rather than trusting someone else’s figure, measure your own.
Sentry Mode uses power. That much is agreed. How much is another matter — you can find claims ranging from 1% a day to 15% a day, and they may all be true, because they measured different cars in different places for different durations.
The only useful number is your car, where you actually park it.
Idle drain is three things, not one
A parked car is not in a single state. MyTeslaCloud splits idle consumption into three modes, which is the precondition for making sense of any of it:
| Mode | What the car is doing | Drain profile |
|---|---|---|
| Sentry Mode | Cameras recording, compute unit awake | Highest, and strongly tied to how often it is triggered |
| Camp Mode | Climate and cabin power kept running | High; depends on set temperature vs. outside |
| Park | Normal standby with periodic wake-ups | Lowest, typically under 1% per day |
Separating the three resolves most "mysterious battery loss" questions on its own — the answer is usually Sentry, and specifically Sentry somewhere with foot traffic.
Why everyone quotes a different number
Sentry drain is not a fixed rate; it scales with how often it is triggered. The car steps up recording when it detects people or movement nearby, so:
- Parked in your own garage, untouched all day — drain can be low enough that turning it off feels pointless;
- Parked in a shopping-centre garage next to the lift lobby — triggered all day, and the loss is obvious;
- Parked on the street with constant passers-by — the most expensive case there is;
- Temperature plays a part too — thermal management kicking in during heat adds consumption.
So someone else’s measurement is of limited use to you. What you need is real data from the handful of places you actually park.
How to measure yours
- Drive normally for at least two weeks so the parking records build up a sample;
- Open idle-drain statistics and isolate Sentry Mode;
- Convert it to percent per hour so parking sessions of different lengths become comparable;
- Compare across locations — home, work, shopping centre. The differences are usually obvious;
- Compare against the Park mode baseline; the excess above it is Sentry’s real cost.
Once you have that, the decision is easy: Sentry costs a fraction of a cent per hour in electricity, and buys you surveillance while parked. Whether that is worth it is now a question with a number attached instead of a feeling.
What you can actually change
- Exclude frequent locations — Tesla lets you mark home and work so Sentry stays off there automatically;
- Set a charge threshold — Sentry switches off below a level you choose, so long parking cannot drain the car;
- Turn it off before long storage — before a trip, switch it off and leave the car near 50%;
- Treat locations differently — skip it in your own garage, enable it on the street or in unfamiliar garages.
All of those settings live in the car. Logging’s job is to tell you whether a change was warranted and whether it worked — check the idle-drain statistics a week after adjusting and the difference is measurable.
