For the 120V side, we have 2 x 30A circuits. Originally, each of the 30A circuits fed an independent electrical panel. One of the panels supplied vital electrical components like the battery charger, inverter, air conditioners, ac pumps, and receptacles for both the port and starboard sides of the boat, while the other panel supplied the hot water heater, and that’s all. When I added the electric block heaters to our heating system, I removed the second electrical panel and moved the breaker for the hot water tank to the first panel

Essentially, Asunto now has a 30A 120V circuit that is dedicated to all the standard house loads. These include the hot water tank, AC, AC pump, microwave, and general receptacle loads (TV, computer, etc). The second 30A circuit is now dedicated to the two 15 A block heaters wired directly to two 20A circuits. This works well as we don’t have any tripping circuit breakers anymore, and we don’t need to worry about turning the heaters off to use the microwave. If we ever need any additional heat, we can always plug a space heater into the port or starboard receptacle and still have enough power for the hot water tank and microwave.

Our generator is also connected into our 120V electrical system. It originally ran both panels, but I have now rewired it to only power the primary electrical. I figured there is no need to power the block heaters, as it makes no sense to burn diesel to run a gen set to power electric heaters to heat water to heat the boat, when we can skip a number of those steps by either running the main engine through the heat exchanger or just run the diesel heater directly.

We also have an 1800W inverter tied into the main panel. It essentially powers everything but the air conditioner, AC pump and the hot water tank. This allows for AC power when we need it, but ensures we don’t drain down the batteries unnecessarily by running appliances that should not be run off the DC system.



The 12V electrical system on Asunto is both extensive and lacking at the same time.

There are a tremendous amount of 12V electrical components on board Asunto. A 50′ boat has a lot of space and a lot of systems, and for the most part those systems are run off of 12 volts. The lacking part of the equation is how dismally small the battery system is on Asunto.

There are a total of 6 x 6 Volt batteries in a series / parallel configuration. This may seem like a lot of power to some boaters and a ridiculously small amount to others. I am definitely leaning towards the later on this subject. We had the same amount of storage capacity on our very first boat. It was  a 37′ boat built in 1969 and was originally built without any electrical systems at all. Fast forward ahead to Asunto, our 1994, 50′ modern sail boat and it has the same battery capacity.

This is on our upgrade list and will likely need to be addressed sooner or later. Right now, I am confident we’d be running our generator at least once a day to stay ahead of the battery drain ( and that is not even being nice to our batteries and keeping them topped up).

I’ll keep this updated when we decide to make a change. I’d like to load the boat up with some nice Odyessy lead AGM batteries tucked away in little corners of the boat, however I am not sure if the budget will allow that straight away as each battery alone is up above the $600 mark.

I suppose time will tell, and hey for now the generator always need a little exercise too.

2014 Update: We had to add a solar panel to keep the charge up while cruising this summer.


Comments are closed.