Battery monitoring
The most important aspect of a long battery life is good management. You should never fully discharge any battery – over-discharge is said to be the single biggest cause of battery failure.
Leaving the boat unused for long periods will undoubtedly result in self-discharge, but even a regularly-used boat can suffer from a flat battery if you ignore how much power is going in/coming out. Also, most batteries only provide a finite number of discharge/recharge cycles, so if you don’t know how many times the battery’s been charged you can’t judge it’s overall condition.
Which is why a battery monitor is a good idea.
You may think the voltmeter tucked among the helm gauges is sufficient. After all, it shows how many volts the battery is delivering and (when the engine is running) how many volts are going back into
