With any vehicle or boat left unused for weeks, there’s a high probability that the batteries will have drained. Batteries naturally self-discharge, so this is entirely normal. Finding that the starter battery is so flat it won’t start the engine is a common occurrence.
In addition to self-discharging, the starter battery of a vehicle or boat may continuously supply small amounts of current to an alarm system, a tracker, or a radio. Over time, even such small power demands can reduce the battery’s ability to start the engine. When a battery reaches the point where it can’t perform its function, it’s not just inconvenient; it’s also costly. The battery will start to deteriorate and require replacement much sooner if it’s kept in a charged condition.
Our battery maintainers keep a vehicle’s starter battery topped up by drawing current from the leisure battery. (Except for the Ablemail unit, they only work when the leisure battery is being charged, either through a solar panel or when connected to a 230V hook-up.)