VoltFX

• Allow Display over other apps for VoltFX. Since Android 10, apps cannot open a screen in the background without it, and Android gives no error.
• Allow notifications (Android 13+) — the charging service needs one to keep running.
• Turn off battery optimisation for VoltFX (Settings → Apps → VoltFX → Battery → Unrestricted).
• On Xiaomi, Oppo, Vivo and some other brands also enable Autostart for VoltFX; these phones close background apps aggressively. The app's setup screen opens your phone maker's setting directly.
• Then tap Test with the screen locked in the app and lock your phone: the animation should appear five seconds later, without unplugging.

Double-tap it, unplug, or wait for the display time you chose in the app.

The estimate needs your phone to report its battery capacity and charging current. Some phones don't; VoltFX then shows nothing rather than a made-up number.

They need real charging sessions: at least 3 minutes plugged in, and a capacity estimate needs a charge of 20 percentage points or more. Short top-ups are skipped so the numbers stay honest.

It rings once per charge, when the level you set is reached while plugged in, and stops when you tap Stop or unplug. Check that notifications are allowed and the phone isn't in Do Not Disturb.

Themes download over the internet and are checked for integrity before they play. Try again on a steadier connection; partly downloaded files are discarded automatically.

Open the app's upgrade screen and tap Restore purchases while signed in to the same Google account you bought with.

Subscriptions are managed by the store, not by us. Android: Google Play → profile picture → Payments & subscriptions → Subscriptions. iPhone: Settings → your name → Subscriptions. Uninstalling the app does not cancel a subscription.