I have had installed recently in my boat a new Centaur 12/100/3 Charger. I have found that the cooling fan never shuts down, despite the charger not charging or charging at a very low level below what might be indicated on the meter. Is this normal operation? Will I have to worry about a fan failure at some point just when it is truly needed to cool the unit? Temperatures in the engine room are still cool to very cool this time of year. Ventilation is good. My former Charles 12/80/3 Charger did not have a continuously running fan. The Lifeline AGM batteries are in three banks of 600AH; 215AH; and 100AH.