Intact Battery-Guard is a free Android app developed by Nils Fett, which enables users to monitor up to 10 Intact Battery-Guard Bluetooth senders. The app displays a tachometer indicating the battery's charge level using a green, yellow, orange, or red bar, along with the exact battery voltage. The app supports 6-, 12-, and 24-volt batteries, and the output is divided into four categories: charged, partially charged, discharged, and deeply discharged.

The app is a useful tool for those who want to keep their batteries in good condition and avoid unexpected battery failures. The app's interface is simple and easy to use, and the Bluetooth connectivity ensures that users can monitor their batteries from a distance. The app also provides a detailed privacy policy, ensuring users that their data is safe and secure.