Battery Charging

• Determine up front how you want to live, what you need/want to live with, and how long you think you will be cruising, before you decide what kind of system you want. You should also decide if you want to be a slave to your boat. Engine or generator driven charge systems require you to run them multiple times a day (in the morning and evening), sometimes for a couple of hours, and even more on passages if using the autopilot. If this doesn’t bother you then the easiest/cheapest system is to put a large alternator on the main engine and/or have engine driven refrigeration. The refrigerator is the biggest consumer of power by far, followed by the water maker. The cost of fuel in foreign ports is typically in the $5 a gallon range, so you can run your engine for a lot of hours before solar panels and wind generators would cover the cost. However, if you consider that you will be putting 1000 hours per year on your engine just to keep the beer cold, then the maintenance/engine replacement costs for any extended multi year trips starts to be a factor.  Gensets are a different story altogether because of the large initial cost, so if you are thinking that route or you like your peace and quiet in the morning/evenings then consider solar or a solar/wind combination. If you feel that you can't leave home without a washing machine, large microwave, air conditioner, air compressor for diving, or any other piece of equipment that draws a large load, a genset is required and is much better than putting lots of hours on the main engine. I’ll admit that I am NOT a fan of gensets, especially after watching a lot of my friends look longingly at me as I went ashore or snorkeling while they were fixing the dreaded beasts or waiting for parts to be delivered.  That said, I also don't have many of the luxuries that it can provide (but I don't miss them either). I didn’t want to give up the room either so I chose solar/wind, and added a 75 amp alternator on my main engine as a backup to solar and wind.
  
  Initially we had 300 watts of solar panels and a Rutland 913 wind generator. I flat mounted the four panels on the arch above the bimini, I figured adjustment isn’t absolutely necessary and it makes you a slave to panel adjustment.  I’ve seen lots of panels tilted the wrong direction because of a wind shift or extra time spent in town. 300 watts worked fine across the pacific until we started hanging out in the SE trades and the wind generator/radio antenna shadow on the panels reduced their effectiveness. I purchased two 80 watt panels in Fiji and mounted them on the rails. I did notice that there was a shadowing effect from the bimini, hard dodger, and boat shade awning depending on the wind direction and angle, but the extra power did help. Once we got to Majuro I added an extra stainless tubing support that goes up and over the bimini and connected aluminum angle rails back to the arch to hold the panels, three on each side of the back stay. Even in convergence zone cloudy weather the boat gets fully charged, while running computers and such at will. The panels under the wind generator and radar are now mounted lengthwise so that any shading effects only a single panel instead of two in the old side by side mounting style. I think 460 watts may be too much, on sunny days we crank the fridge all the way up and still can’t use all the power (but KT loves it). I’m sure running the water maker will help use some excess once we get out of the wet water catching zone.
  
  I got lucky because I bought my boat from the local stainless steel arch builder who built me a great arch and stern rail combo. However, we have never taken down our bimini, except to clean or adjust the solar panel installation. I saw a VERY nice fiberglass bimini top, with built in rain catching gutters, that would have supported a good set of solar panels. In Singapore I saw a lot of boats with permanent  biminis, some upgrading to fiberglass. I also had an old Hans Christian that had solar panels mounted on top of the dodger on an extra frame (which wouldn’t work for us now because we need the full boat shade). One could do the same above a heavily built bimini or directly on the bimini if water intrusion issues could be solved around the mounts. Don’t forget to take these mounting costs into consideration when comparing the costs. We unplugged our boat from the dock months before we left to make sure we were keeping up with things - we were usually fully charged by noon.



• The Flexcharge NC-25 charge controller has been great and I hook the divert load to a 12 volt hot water heater element - who wants to add heat to the air in the tropics with a resistive load?  I have two, one is connected to the wind generator and 150 watts of solar panels (with a diode on the solar) that I can switch between the house and engine battery banks, the other contains the rest of the solar hardwired to the house bank.



• Link 20 Battery monitor – I wish they had an external trigger that could be hooked to the NC 25 charge controller so IT can determine when the batteries are fully charged. It is still very helpful in determining battery state. We have two house banks that we keep permanently paralleled, the link 20 allows us to monitor any differences in the two banks, however you could use a single battery monitor to cover the house bank.



• Use a simple volt meter for the starter bank if the engine is not used frequently (allows voltage to stabilize to give an accurate reading of battery state).



• Wind Generators do not work well for trade wind sailing because the apparent wind is lower. We supplement ours with a home made towing generator. The AQUA4AEROGEN looks like a good solution that is optimal for both anchor and sea conditions. I recommend a permanent pole mount because the violence of squalls can make the fore triangle mounted generators dangerous to take down.
   
• Inverters: believe or not we use a simple 700 watt inverter that came with battery clips that I hard wired to the boat. It was simple, cheap and I bought two for $50. It is modified sine wave but we have never had any problem with any electronics we've used. We have a friend who burnt out two washing machine circuit boards using a non-sine wave inverter, so be careful if you are installing large heavy draw components or invest in a pure sine wave one from the start.

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