Off Grid or let's say "Independency"
 

 

When designing an off-grid (not connected to utility power) solar or wind power system, it's very important to have an accurate estimate for how much energy you need. Off the grid systems must utilize batteries to store DC power from the solar panels and convert it to AC power with an inverter. If you are not storing enough energy, you will decrease the life of your batteries, possibly ruin your batteries and most importantly, your power will eventually go out. An electrical system does you no good if it can't provide you with the necessary energy to properly run your home, RV or boat. This is why we do a load evaluation. The computation helps us determine roughly how much energy your home will need.  If a device is drawing energy, no matter how small, it will have an impact on your solar system. Lets examine some electrical loads as an example.

The behaviour of every family and familymembers differs sgnificantly. Some like to work at nighttimes on computer or do the daily cores like washing and cleaning. Some others sleep early while they have to get up early morning. Normally these loads by themselves would probably not adversely affect your system, but if they all get used in the same day, it could have a large impact upon your stored energy. In the morning, you may use the microwave oven before the sun rises and the microwave has dropped the battery storage below 50% capacity. This is when batteries start becoming damaged and it's irreversible. Damaged batteries will significantly reduce the overall performance and storage capacity of your system which will only exacerbate the problem. Batteries are far too expensive to allow them to be needlessly damaged or ruined. We will add in a buffer amount of capacity to the design to account for inefficiencies and small phantom loads like a digital clock on your microwave and the idle power draw of the inverter.

Technical Note: Many people have a difficult time understanding how watts are calculated and how that relates to energy. Basically, the amount of power a device consumes is rated in watts. This is most easily seen with the old-fashioned incandescent light bulbs. Those have the wattage rating listed on them: 25W, 50W, 100W, 150W etc. The new LED bulbs, witch are included in our packages, do not draw nearly as much power as their incandescent equivalent but they often list the incandescent equal in light output. So if you have a LED bulb that puts out the same level of light as a 50 watt incandescent, that does not mean that the compact fluorescent consumes 50 watts of power. It probably uses about 3 or 9 watts compared to the 50 watts. The packaging will normally tell you exactly how much wattage the compact fluorescent actually consumes or it may even be listed on the base of the bulb. If you need to know the rated wattage of other electrical devices, such as your T.V., you can often find that information listed somewhere on the device. If it does not list the wattage but tells you the amperage and voltage, you can calculate the total watts. This is done by using a formula derived from Ohms Law. If you can't find the watts, voltage or amps listed on the device, we have included a basic wattage chart with the computation for most devices and appliances. Your device may consume a little more or less than what is listed on the chart, but it will give you a pretty good estimate. For those that want a very accurate energy or power measurement for a device, we can measure it with a watt meter.

Here is how you can calculate the watts if you know the voltage and amperage of a device.

Watts = Volts x Amps

If your T.V. plugs into a standard 220 volt receptacle and uses 1.2 amps, the total watts is calculated by multiplying 220 volts x 1.2 amps. That equals 264 watts.

220 Volts x 1.2 Amps = 264 Watts

Watts is an instantaneous value. Knowing the wattage of a device is necessary, but it does us no good unless we know the length of time that the device is turned on. When you multiply time by watts, that is called energy and it is measured in watt-hours. To be clear, 1 watt is NOT equal to 1 watt-hour or 1 watt per hour. If you have a device that consumes 1 watt and use that device for 1 hour, that is equal to 1 watt-hour. If you powered that same 1 watt device for 2 hours, that would equal 2 watt-hours. It's simply watts multiplied by hours which calculates the energy needed. Once we know how much energy you use, we can then design you a system that will meet all of your electrical needs. We are here to help!