Advertising Buying a Tesla for the first time comes with a learning curve, and not all surprises are welcome. Sometimes, those surprises don’t come just from driving the car; they come from what happens when you don’t. And while scrolling through the “Tesla Model Y 2025-2026+ Juniper” Facebook group today, I came across a post by Brian Ashby that stood out to me for that reason. After leaving his 2026 Model Y parked in his garage for a week, Brian discovered that the battery had dropped from 79% to 36% without Sentry Mode enabled. A 43% drop that quickly sparked questions about how Tesla’s background features might quietly chip away at charge even while the car appears idle. In Brian’s words: “1 month with my new 2026 Model Y, and the battery went from 79% down to 36% while just sitting in the garage for 1 week (7 days exactly) while I was out of town. This is a bit disturbing to lose 43% of the battery in 7 days. Am I doing something wrong here? I didn’t have it plugged in because I wanted to see how much I would lose and I didn’t take it to the airport and so I left it there because I didn’t trust that it would have enough battery to get home when I got back. I have plenty of gas vehicles and just bought this one to see what it’s like. I do like the car, but this is not great. Also it’s not in Sentry mode, but it is set to cool if it’s over 100 in the interior, so maybe that’s the whole reason. But that seems like a lot of battery use for just sitting in a garage for a week. The weather wasn’t over 100 the whole time.” How Other Owners Compare This scenario is one that’s familiar to many new Tesla owners: a combination of curiosity, real-world experimentation, and unexpected results. And based on the responses to Brian’s post, his situation is not exactly the norm if the proper steps are taken. Sanjeewa Kalupahana shared his own experience with a much more favorable outcome. “I parked the car for 10 days in a parking garage while I flew away on a holiday. Had all of those things turned off and my Tesla app was showing the car was in deep sleep. I left the car charged at 81%. After 10 days, it was showing 80%. So only 1% loss in 10 days. This is the new Model Y in the UK.” His situation highlights a contrast of what happens when you make sure to turn everything off. With Cabin Overheat Protection and Sentry Mode off, and no regular wakeups via the app, Sanjeewa's car barely sipped any energy at all over the course of more than a week. Similarly, Mehmet Akkuş noted, “Mine has been sitting for 9 days and lost 2% so far. Sentry mode off and overheat protection off.” Again, this shows that when the right settings are in place, the car can remain mostly idle without major loss. It's worth mentioning that disabling Cabin Overheat Protection isn’t something everyone is comfortable with, especially in hot climates, but it clearly plays a significant role in this kind of energy draw. One of the more philosophical responses came from Joao De Deus Anacleto, who took a step back to look at the broader picture: “Don’t worry and fret, especially knowing that 100’s of thousands of Model Y owners in the world over have figured out how to leave their vehicles alone for weeks at a time. Do you honestly believe 10’s of thousands of Tesla engineers would sell you a sub par car based on nearly a quarter century of EV design and build experience? Probably not. Try leaving your explosive gas car on Sentry Mode and Cabin Overheat Protection and see how much gas is left in the tank after weeks… oh, they don’t have those features do they, so it can never be an apples to apples comparison.” An uncompromising stance to say the least, but what he's getting at is true though. With proper precautions and understanding of your car, you can certainly limit this not so phantom drain. Another user, Ray Lopez, kept things practical: “Make sure your Sentry Mode is shut off. And your climate control is OFF and that it’s NOT set to a temperature. I went on a cruise from Miami for a week and lost 3%.” It's clear that seems to be the recurring theme: if the car is truly asleep and those extra protections are disabled, energy loss becomes a non-issue. Advertising