Wednesday, March 9, 2011

Solar Conversion of our Homestead

Hi everyone,

As the time begins to draw closer for our move to the homestead, I find myself thinking about the various projects which lie ahead for me. We have the fruit trees to plant, a garden to start along with a host of addition important functions to get accomplished. One of my initial goals will be to get a 12 volt lighting system installed which will operate from rechargeable batteries.

These systems are not new in the least and have been in use with the recreational industry for decades. I experienced the systems first hand often in the past and actually had the opportunity to use them for an extended length of time a year or two ago when I initiated a six month long bug out exercise. With the new LED lighting systems out today the intensity of the lights have been drastically improved while battery drain has been decreased.

My goal is to establish initially two separate electrical systems which can compliment each other. The first system will operate as it usually would in any home – from the 120 volt input line voltage. The second electrical system will operate the lights and perhaps a few appliances if necessary. This will be the battery operated system with charging being accomplished by a solar cell collection.

This at first sounds pretty great with having two systems connected – a prime along with a backup but let’s remember the ultimate idea is to remove the family from the 120 volt electrical requirement eventually.

My cost estimate for this retrofit of my home electrical system is approximately $800.00 which includes about $200 for the materials and supplies to complete the installation and $600 for the solar cells themselves. Since I am an old and decrepit man these days I have spread the project out over a short period of time and broke it down into several phases.

At the conclusion of phase one, I should be able to have about a two day supply of 12 volt power running into the home which will permit me to operate several small appliances if necessary. It is hoped that if everything comes out as expected I will be able to use my laptop, operate all the lights and perhaps use a small microwave without placing a demand on the commercial electrical supply.

Phase two will be the actual installation of the solar cell system to recharge the battery banks sufficiently.

Materials necessary for phase one will initially include

* Two deep cycle marine batteries.

* One 1,000 watt inverter to change the battery power to our common 120 household AC. * Necessary power cables and house wiring needed to complete the installation.

A small building will house the batteries and the associated equipment during phase one and the solar system will mount on the roof of that building during phase two. This will keep the equipment and the batteries away from the elements and allow me to expand the number of deep cycles connected to the system slowly over a period of time.

Connecting the batteries together and into the system is a simple matter. We merely need to connect the two batteries to each other with a short cable. It is best for future maintenance and troubleshooting to employ a standard color code system as the project progresses. In this case, we will connect red power cables to the positive terminals of the batteries and black ones to the negative terminals. This type of connection is referred to as a parallel connection and affords your system greater current capacity then would the usual series connections.

Next, we would need to connect the batteries to the 1000 watt inverter. Once again the red cable will connect to the positive terminal of the other battery as well as to the positive connection of the inverter. Similarly the black cable will connect from the negative battery terminal to the inverters negative connection.

All that is left would be to connect the battery system to the installed 12 volt lighting wires that have been installed inside the home. That is actually the most time consuming part of the complete project. Before we close this phase I would like to stress a few safety hints to those who may be planning to perform the same modifications to their homes.

Make sure that you protect your system by having a series of 12 volt fuses placed in line. My intent is to use a Plexiglas panel and install the fuses on it sort of a rack mount fuse array. Connect your fuses to the positive or red cable side of the system.

The same will apply to your inverter in the event that it has no fuse already in place. Put a 110-amp Class T fuse into the red or positive cable line between your battery packs and the inverter itself. Keep in mind this fuse is a special type of DC fuse and not your usual AC variety. For safety sake nothing would prevent you from installing an AC fuse on the opposite side of your inverter as well.

If you have a considerable distance for your cables to travel consider heavier cables. Always remember that the longer your cables are the heavier wire will be needed. Longer cables often experience voltage drops. Thin cables tend to get hotter then the thicker ones do. In most cases a number 14-ga should do the trick.

You may also wish to install a good grounding rod to prevent unforeseen problems. RV’s generally do not have an external ground but it is better to be safe than sorry.

You may spend a few dollars more when purchasing an inverter but try to get one with a low-voltage warning light and a low-voltage automatic disconnect (LVD) in order to shut off the power to the inverter in the event that the battery voltage reaches a dangerously low level. If you deplete your batteries too much they tend to become damaged and their life is drastically shortened.

When selecting your batteries you should purchase the marine deep-cycle types and not the regular automotive batteries. They cost more but are better for our purpose here. The difference in the batteries is that the usual auto type batteries are used primarily to start your car and then sit idle as it is charged whereas the deep cycle versions are made to run for hours at a time.

You should be able to run your laptop, a small microwave and a 70 watt lamp at the same time on this system. As you can readily tell I will have to add greatly to the starter system in order to be able to function as a normal home.

During our phase two project I will be adding the necessary solar panel and its associated charge controller to the system. A charge controller will control the amount of power going into our battery banks and keep it at a measured amount. It also ensures that our solar cells do not take the energy back out of the batteries. These too will have additional panels installed as we progress in our challenge here.

I expect to start the phase one work in the spring or possibly early summer.

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