Wind Horse and the FPB64 have similar AC and DC systems, so we thought you might be interested in how this is working out in the real world.

The power consumption at anchor on Wind Horse comes primarily from the AC requirements which are satisfied with three 2500 watt Victron inverters. These AC loads are mainly:

• Computers (dual monitor Mac and portable PC) which average an easy 12 to 15 total operating hours a day (and sometimes more).
• Variety of small appliance chargers.
• Occasional (daily) use of air conditioner(s) for dehumidification.
• Galley requirements (all cooking now except for baking and roasting).
• Washing and drying cycle with full sized washer and driers.
• Entertainment (42″ plasma TV, home style tuner and surround sound system).

DC power at anchor goes mainly for:

• Lighting – all via halogen bulbs.
• Diesel boiler for heating the boat and domestic hot water (boiler and fan coils are 24VDC).
• 12 chargers supplied via a 24-12V converter.
• Anchor light.
• Two freezers and fridge.

We have 1600 amp hours (20 hour rating) of sealed traction batteries in one large bank. The amp hour meter typically gets down to about 65% (from 100% after passaging) in three days. This includes using the drier on average every other morning to dry our bathing towels. If we have used the washer and drier in a full cycle we will be at 65% after two days.

Without doing a wash cycle we will see 45% on the amp hour meter in six days, which is the longest we ever sit anywhere.

When we are not busy with the computers (a rarity but it does happen) power consumption drops significantly.

In the tropics, when the heater is only used for domestic water heating, the power saved here seems to be offset by slightly higher refrigeration loads.

Two or three times a year we want to cycle the batteries down to 30%. This is actually good for them. To do this we will run the air conditioning or do one or two full wash/dry cycles. We plan this when we have a long passage coming up and lots of time to fully recharge the batteries underway using our engine mounted Electrodyne 150 amp/28VDC alternators with remote rectifier assemblies.

The genset is rarely run. After five seasons of cruising (roughly the equivalent of 2.5 years) the genset has 600 hours on it. 100 of these were during sea trials when we were trying to set the rings (the 8kW Northern Lights genset was very smoky early on). Another 50 came in Alaska when our boiler had a problem and we were using our reverse cycle air conditioning to stay warm. So the actual usage works out on average to about 15 hours a month.

If we are sitting around a lot and making short passages, like much of this past summer in Norway, the genset will be run every second or third day for the wash cycle. We will often combine this with watching a movie, the excess genset capacity being used to charge the batteries.

The FPB 64 has a 1200 amp hour traction battery bank, the same alternators, similar inverters, and a slightly larger genset (11kW).