Η εφαρμογή μου στέλνει ειδοποίηση όταν τελειώνει η μπαταρία.

The app sends me a notification when the battery runs out.

Breakdown of Η εφαρμογή μου στέλνει ειδοποίηση όταν τελειώνει η μπαταρία.

• μου: my
• μου: me
• στέλνω: to send
• όταν: when
• η ειδοποίηση: the notification
• η μπαταρία: the battery
• τελειώνω: to run out
• η εφαρμογή: the app / the application

Questions & Answers about Η εφαρμογή μου στέλνει ειδοποίηση όταν τελειώνει η μπαταρία.

Why is it Η εφαρμογή μου and not Η μου εφαρμογή?

In Modern Greek, short possessive pronouns like μου/σου/του/της/μας/σας/τους normally come after the noun:

• η εφαρμογή μου = my app Putting μου before the noun (η μου εφαρμογή) is generally not used in standard Modern Greek (it sounds archaic or dialectal).

What exactly is μου doing here—ownership or “to me”?

Here μου shows ownership: η εφαρμογή μου = my application.
Greek also uses μου as an unstressed “to me” object (e.g., μου στέλνει = sends me), but in this sentence the μου attached to εφαρμογή is possessive.

How would I say “My app sends me a notification…” explicitly?

You’d add another μου (this time as an indirect object clitic) with the verb:

• Η εφαρμογή μου μού στέλνει ειδοποίηση όταν τελειώνει η μπαταρία.

In everyday writing, many people avoid μού (stressed form) and just write μου twice:

• Η εφαρμογή μου μου στέλνει ειδοποίηση...
  It’s common, though it can look a bit repetitive.

Why is there no word for “a” in στέλνει ειδοποίηση?

Greek has no indefinite article equivalent to English a/an.
So στέλνει ειδοποίηση can mean sends a notification (often a general/habitual sense).

If you want to make it more specific, you can add:

• μια ειδοποίηση = a notification
• την ειδοποίηση = the notification

Why is ειδοποίηση in that form—what case is it?

ειδοποίηση is the direct object of στέλνει (sends), so it’s in the accusative.
For many feminine nouns ending in -η/-ση, nominative and accusative singular look the same:

• nominative: η ειδοποίηση
• accusative: (την) ειδοποίηση

Why does Greek use the definite article in η μπαταρία? English says “when battery is low/runs out” without “the”.

Greek commonly uses the definite article where English might use no article, especially with familiar, context-based nouns:

• όταν τελειώνει η μπαταρία = when the battery runs out (i.e., the device’s battery)

You could also specify:

• η μπαταρία του κινητού = the phone’s battery

Why is it όταν τελειώνει (present) instead of a “future” form?

Because this sentence describes a habit/general behavior: the app sends a notification whenever the battery runs out. Greek often uses:

• όταν + present indicative for repeated/habitual situations.

If you mean a single future event (“when it finishes [in the future], it will send…”), Greek commonly uses:

• όταν τελειώσει η μπαταρία (subjunctive/aorist after όταν in future reference)
  and then often a future main verb, e.g. θα στείλει.

Does τελειώνει η μπαταρία literally mean “the battery finishes”? Is this normal Greek?

Yes, it’s normal. τελειώνω is used for things that run out:

• τελειώνει η μπαταρία = the battery runs out Other common options:
• αδειάζει η μπαταρία = the battery empties/drains
• τελειώνει το μελάνι = the ink runs out

Why is the word order στέλνει ειδοποίηση όταν...? Can I move the όταν clause?

Greek word order is flexible. The given order is natural: main clause first, then time clause.
You can also front the time clause for emphasis:

• Όταν τελειώνει η μπαταρία, η εφαρμογή μου στέλνει ειδοποίηση. (Here the comma is common because the subordinate clause comes first.)

Should there be a comma before όταν in the original sentence?

Usually no. When the όταν-clause comes after the main clause, Greek typically does not require a comma:

• Η εφαρμογή μου στέλνει ειδοποίηση όταν τελειώνει η μπαταρία.

A comma is more typical when the όταν-clause is placed first:

• Όταν τελειώνει η μπαταρία, ...

What’s the difference between εφαρμογή and app in Greek—do people actually say εφαρμογή?

Yes. εφαρμογή is the standard Greek word for application/app. In casual speech you may also hear the loanword app (often written απ or app), but εφαρμογή is perfectly natural and common, especially in writing.