Power Design

[RJC]

I'm looking to refit a Motor Cruiser.

 

It will be (or could be) on Shore Power 24/7 as its going to almost always be in the Marina. I will probably only be onboard sporadically.

 

I'd like a 240V Fridge, Oven and some 240v 13A sockets. The boat has two batteries and chargers and a 12V system at the moment which includes the pumps, lights etc. 

 

- Would the best thing be for me to get an Inverter/Charger and leave the shore power connected all the time so the batteries constantly charge? 

- What would the implications be of introducing Solar Panels into the system. (Could i have the batteries charge via Solar and default to Shore power when necessary)

- Would it be advisable to keep everything going back to the main batteries (some direct 12v, some via an Inverter) or have 2 x wiring systems in the boat, 1 direct 240v shore power and the other via the Batteries?

 

Rob

[nicknorman]

I would just get a decent inverter-charger (Combi) by Mastervolt or Victron. These will pass through mains power when connected -whilst keeping the batteries charged -, or invert from battery to supply mains when shore power not connected.

 

You could add solar panels, setting the controller’s voltage above the Combi’s charge voltage so they took priority - but I question whether it would be worth the cost, hassle or ugliness for a boat primarily on shore power.

 

Generally it is a hassle to have 2 separate mains supplies, some things will not work when not on shore power. The only exception would be for things that you don’t want to work when not on shore power. For us, that is nothing. But some people like to have the immersion heater only working on shore power.

 

What happens is that the supply comes onto the boat, into the Combi, out of the Combi and then to the consumer unit and sockets etc. You can choose to connect the immersion heater either to the Combi input (only works on shore power) or Combi output (works on shore power or inverter).