Nobody likes to suddenly be without power at sea. You can read the current power consumption on the ammeter in analogue or digital form. If you like it compact, you can buy a battery monitor, for example from NASA. It provides you with both values.
You have even more overview and control if you bundle not only the measurement data but also the most important switches directly on a panel, for example position lights, anchor light and interior lighting. Choose the option that best suits your needs on board.
If you are no longer really satisfied with the performance of your on-board battery, even though it is not old at all, you can give it a "cell cure" with Megapulse. We offer the marine version here with a higher activation voltage.