Posted by: livingaboardspellbound | July 10, 2013

Solar, wind, and batteries Oh My!

When you are outfitting your boat for cruising one of the most important aspects to consider is power usage and power production. Knowing how many amps you use daily and if you anticipate adding electrical items such as refrigeration, freezer, fans, etc… you will need to know how many amps they use. To accomplish that there is a gadget called a system monitor that allows you to see at a glance how many amps you are using and can monitor two battery banks. The one we looked at is the Trimetric 2025. It is labeled in this link as RV but can be used on boats as well.

Once you have the number of amps that are being used (plus the estimate of future amps needed) you can then apply this number to this equation: AMPS X VOLTS= WATTS then divide by 3 for low latitudes or 4 for higher latitudes. For example if you using150 amps X 12 volts= 1800 watts/3= 600 watts of solar/wind power needed. If you are in the Caribbean you definitely need to consider wind power as well as solar. There is always at least a 10 knot breeze, and if it is not sunny it is usually windy.
If you don’ have a system monitor or don’t want to purchase one, there is a worksheet you can you to calculate amps used. here is an example:

The company we have decided to use for our solar/wind products is S/V Hotwire. John and Libby are a couple that has cruised the Caribbean extensively and know what you need and are there to help you every step of the way. They run their business out of their home and we went to visit them recently. They welcomed us right in and were eager to talk about solar, wind, and cruising in general. The website is a little difficult to navigate, and they are working on making it friendlier, so my suggestion is to call them directly or if you are within driving/sailing distance of Tarpon Springs go visit them. if you sail there, you can dock at the Tarpon Springs City Marina. It is in the heart of the sponge docks and some great greek food! They charge $1.50 per foot, which in my opinion is very reasonable.
S/V Hotwire sells several different brands of solar panels in all sizes to meet your personal needs. The wind generators they sell are KISS Systems. They also have all the accessories and hardware you might need.
There are many schools of thought on batteries. Some think 6v golf cart batteries are the best, while others think deep cycle AGM’s are the way to go. Our personal thought is for the AGM’s. We like that there is no maintenance for them, no worry about spillage or damage from acid leakage, and they come in many amp hour sizes. We currently have 2 Duracell deep cycle marine batteries that are 105 amp hours each. We plan to have 6 total for our house bank and 1 for our starter bank.
Obviously there will more to come on this subject when get this project going.


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