I was leaving my boat with everything OFF including the charger thinking it was not necessary and preventing any zinc usage by unplugging the shore power. After returning in 2-3 days, I would find that the Starting battery was below 12V with the alarm flashing while the House battery had it's full charge. mmmm major issue here and a challenge to identify problem. I spend hours taking volt reading at all different locations and with different switches on and off. I thought maybe was the windlass contactor sticking but that was not it. It turned out that it was the Max-Power Thruster Control Box (not the panel at the helm) which is powered (as per manual) by a separate battery than the thruster and it only has an 8A breaker. The thruster battery is a dedicated one sitting right next to the motor without a way to disconnect it. It has a 200A fuse but not a breaker. So even when you think that the thruster of OFF by turning it OFF at the helm, the Control Box contactor is still active and using some power from the "other" battery, in my case the Starting battery and that's why it was being drained. Turning the 8A thruster breaker OFF will prevent this by cutting power to the control box...but who would think that! I have the option of connecting the control box to the house bank instead of the starting bank to prevent accidental draining while sailing but I could introduce another problem to the house bank. I have to really think about it before I do it.
So when you turn the engine off and enjoy sailing, be aware that the thruster control box still needs power unless you turn off this breaker or the battery supplying it. Just thought I would share this experience with those who like to turn off the charger for the winter.
So when you turn the engine off and enjoy sailing, be aware that the thruster control box still needs power unless you turn off this breaker or the battery supplying it. Just thought I would share this experience with those who like to turn off the charger for the winter.
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