Continuing preparation of Every Day for our trip has taken an interesting turn. Starting with the belief that the boat could sail out of the harbor today and do just fine, we are focusing on making critical systems (sea anchors, water makers and the like) more accessible and as dependable as possible.

Our boat has a very nice single side band radio. Neither Mallory nor I know anything about them. We need help. Does anyone know about getting our SSB license? Please let us know so we can get the paperwork started.

Now on to the main topic of discussion for this month. We have had many discussions with different people in energy management for marine applications. In the past, boats always had three battery banks. Engine starting battery was connected only to the engine starter and two house load battery banks. To deal with charging of these banks charging distribution equipment was adapted to these systems. Unfortunately, each battery bank is only as strong as the weakest battery. Uneven loading and cycling have made multiple bank systems less dependable and more wear on the batteries than two battery bank systems.

With the introduction and popularity of battery monitoring/inverter/battery charging systems and boats having multiple power sources (shore power, generator, solar, wind etc.), the shift is to have one starter battery and one house battery bank. The battery monitor measures voltage (an indication of how full the batteries are) and usage (in amps) and gives you a count down from full battery level. No house battery should be discharged below 50% of full capacity. These monitors will allow you to know when to charge. Since the entire bank will be discharged and charged together all the batteries will have the same wear and most importantly high output alternators or other high rate charging systems will have a slower overall uptake thus increasing the total absorption of power into the batteries. Almost more importantly, by knowing when you "need" to charge you can go longer periods of time without charging because you have the availability of the entire house battery capacity (not half as you have in a two bank system).

All of the power sources feed or charge the battery banks system. These different sources do not need to be managed separately since each system, solar, wind, water generator, auxiliary generators, engine alternator or shore power charge the batteries, any or all of them can operate at the same time and will charge the batteries until they are full. As they are charged the battery monitor will count backwards until it indicates the batteries are full. This insures that fuel is not wasted when batteries are already full.

Lastly, or at least for now, tank measurement. If you've ever run out of gas in your car is not fun but running out of fuel or water in the ocean can be life threatening. The hart tank monitoring system uses pressure to determine tank depth and cannot be plugged and can monitor fuel, water and head tanks with the same system. It can't be more simple. You press a button to pump air into a tube that goes to your tank and when you stop the liquid in the tank presses back on the air in the tube, thus giving you an accurate measurement of liquid depth. That measurement times a factor for the dimensions of your tank and you have volume in gallons. We are installing this system to insure that we know how much fuel, water and waste we have aboard.