The Luxuries

The essentials are out of the way, how about the luxuries?  I think of budgets whenever starting out on a new project.  Most of the time that is “how much money?”  On a boat, it is more complex.  Anything on a boat consumes:

·        Power

Solar cells can provide a minimum acceptable level of refrigeration, lighting, and power for the autopilot.  The Voyage factory has limited us to 200 watts of maximum solar cells.  This is almost sufficient to operate either our fridge and freezer on a sunny day.  If we are careful with power usage, we can limit our charging to every other day.  We hope someday to install the additional 200 watts we requested and avoid charging for routine operation on sunny days. 

The twin Yanmar 27 HP diesel engines are each equipped with a factory supplied 55-amp alternator, easily enough to supply a comfortable load if run a number of hours per day.  The factory offers an optional upgrade to twin 120-amp alternators, but we believe the factory supplied pulleys and belts are insufficient to drive the larger alternators.  Several Voyage Yacht owners have reported breaking factory belts on frequent intervals when using larger than 55 amp alternators.

I wanted to meet several conflicting goals:

1. Charge the batteries as quickly as possible when the engines are not otherwise required.

2. Provide a very large supply of electrical power to meet luxury demands such as computers, air conditioning, and washing machine.

3. Maintain the Yanmar-supplied starting and start-battery charging systems in original condition to maximize reliability.

I turned to Voyage Yachts to find what optional alternators are provided.  The factory did not offer a larger alternator that met my requirements.  Yanmar placed maximum power limitations on the power that could be drawn of the auxiliary pulley.  The power I required was higher than the Yanmar maximum for the single pulley system they supplied.

How do we fix the power budget?  Yanmar provides space to mount a heavy duty duel pulley power take-off on the front of each Yanmar engine.  This power take off (PTO) is rated at up to 5,000 (5kw).  Both A/C generators and DC alternators are available in the 3,000 watt to 5,000-watt rating and will potentially bolt to the front engine mounts and provide the power required.  We purchased two of the power take off pulleys and trimmed off some of the metal on the engine side of each.  We had this done because the alternators we selected would generate a large side-load on the crank shaft - and a thinned pulley reduced that load.  We also had the new alternators positioned so the side load was partially offset by the load caused by the alternator belt and the salt water belt originally provided by Yanmar (see photos below).

I purchased two Balmar 95-210 (210 amp)  (about 3,000 watt) alternators and had Herman (the German) Zimmerman, a South African welding artist build the necessary brackets.  Herman installed the twin Balmar alternators and Balmar regulators I brought from the states.  These units delay 45 seconds after engine start before applying their load and charging the batteries.  This delay is a valuable design feature that helps your engine warm up smoothly before slamming them with a heavy load.  The result is less smoke and more power.

The regulators and alternators have worked as designed, providing the charging current and when demanded running the base load of our washing machine, air conditioning, microwave, iron and anything else we thought of including two computers.  Unfortunately, a quirk in the Balmar regulator design became apparent over the first few months of use. 

Herman's work was perfect.

Here are pictures of the finished product: 

Double click on a picture to see it in greater detail.