One of the biggest challenges the Apple Watch faces is battery performance. It could have the best UI, deep integration with iOS and powerful features, but if it doesn’t get users through a heavy day’s use, what’s the point? A new report from 9to5Mac has revealed Apple’s projections for the device’s battery life, and they don’t sound overly optimistic.

Sources speaking with the news outlet say the Apple Watch will take advantage of a powerful processor and high-quality screen, which will be the main contributing factor to the device’s poor battery life. Like, really bad.

As a pure time-keeping accessory, the Apple Watch will apparently be able to display its clock face for only three hours before dying. That’s… not good. And it sounds like that experience extends to heavier application use, which sources claim is less than three hours (around 2.5 hours); standard app use is apparently rated at 3.5 hours. If that’s the case, you’ll have to charge your Apple Watch before lunch, otherwise you essentially have a nice looking Thing on your wrist, and nothing more.

The processor inside the Apple Watch, S1, is apparently similar performance-wise to the A5 found in the current-generation iPod touch; the display will chug along at a fluid 60 fps, which means demands to even pump content to your eyeballs will be intensive. And, 9to5Mac claims, not so friendly to overall battery.

Fitness tracking features will apparently get users around 4 hours of battery, likely because the device’s display will be off while you’re sprinting around Central Park.

Battery will obviously depend on how many notifications come streaming in and what you’re actually doing, but the more the Apple Watch display is on, the shorter battery life will be. Chances are the screen won’t constantly be on as you use it—you typically use a smartwatch passively—so you should be able to get through an entire day. That’s Apple’s hope, anyway. At least the company has been realistic by admitting the Apple Watch will need to be charged nightly.

Apple has apparently been working on improving the Apple Watch’s battery for the past year now, which is why it has taken the company so long to release it. The device will reportedly come out in March, so any lingering battery issues Apple had have seemingly been taken care of. But if 9to5Mac’s sources are correct—and they usually are—don’t expect stellar battery performance when Apple Watch becomes available.