Group: Forum Members
ChrisJ (and Simon),
I have no experience with wiring a bowthruster and/or windlass. What I do recall is that both take so much energy that you either have a very large, expensive, heavy battery pack up front or need to run your main engine while using them in order not to deplete the bow battery pack. Using a 240v link in beween does not change that.
Therefore, if you use the 240v approach (which sounds logical to me), you still need to take into account the energy usage of the invertor that provides the 240v power. If, say, the windlass / bowthruster uses 1000W, this will use ~80Amps from the battery pack. Therefore (taking into account the losses of converting 12v -> 240v -> 12v) you need maybe 100Amps at the primary batteries if you want to provide the whole power intake, or at least 50 Amps if you want to power half of the power intake from your 240v system.
That said, it seems to me that you need to check whether your alternator and main battery pack are currently up to that depletion for short periods of time. If so, no problem, if not than you need to upsize either main battery pack, alternator or both!