Knowing the voltage of a battery ensures a long battery life. On small boats, however, space - and often money - is tight for a permanently installed battery monitor. What everyone now has in their pocket, however, is a smartphone. And this is also suitable as a display for the on-board battery. At least if the Intact Battery-Guard, which costs 30 euros, has been connected first.
This is connected to the pole terminals via a ring eyelet and sends a signal to the free app via Bluetooth. The power consumption for this is less than 2 milliwatts, and the range is sometimes much higher in practical use. An undervoltage alarm can be programmed. Suitable for 6, 12 or 24-volt systems.