# Filling out a load chart

Below are a couple of load charts. You should make up your own blank example for your own system. The purpose of a load chart is to determine what you want to run and how much power it will use. Below is a pretty basic method of determining your power requirements.

The first chart below is for a small cabin with some really basic appliances. It assumes 4 sun hours per day and factors the load by 0.7 to allow for inefficiencies.

 Appliance Wattage Hours (per day used) Electrical load Reading light 15 x 2 = 30 Living area light 20 x 4 = 80 TV 120 x 3 = 360 Phone charger 8 x 1 = 8 Total Daily power requirement 478 Efficiency factor 0.7 (478 divided by 0.7) 682.8 Total load to give 4 days autonomy: (683 x 4) 2732 Battery voltage: 12 volts, battery capacity determined by maximum discharge of 30%. 2732 = 30%. 100 % determined by (2732 ÷ 30) x 100 9106 (watts) Battery capacity in amp/hours = 9106 ÷ 12 758 (amp/hours) Solar array size based on 4 sun hours per day average = factored power requirement (683 watts) ÷ 4 (sun hours per day) 171 (watts)

The following chart is for a house with a typical requirement given a set budget. With a household solar design it is far better to use the more comprehensive design criteria of Australian Standard (AS) 4509.2 - 2002 but this chart displays the basics for a house with basic (as far as Aussie homes) appliances and typical needs

 Appliance Wattage x Hours per day (Note 1) = Electrical Load Lighting Living room 20 x 4 = 80 Dining room 20 x 4 = 80 Bedroom 1 15 x 1 = 15 Bedroom 2 15 x 1 = 15 Bedroom 3 15 x 1 = 15 Bathroom 15 x 2 = 30 Study 15 x 2 = 30 Outside 50 x 0.5 = 25 Others (laundry, toilets, shed etc) 60 x 1 = 60 Total lighting load 350 Kitchen Refrigerator 140 x 6 (note 2) = 840 Blender 500 x 0.2 = 100 Microwave 1500 x 0.5 = 750 Juicer 600 x 0.1 = 60 Total kitchen load 1750 Lounge Room TV 140 x 4 = 560 DVD 25 x 2 = 50 Stereo 25 x 1 = 25 Computer 140 x 2 = 280 Total lounge room load 915 Bedroom Appliances Electric blanket x 1 120 x 0.5 = 60 Kids TV 80 x 1 = 80 Kids TV 2 80 x 1 = 80 Rechargeable devices 40 x 1 (Note 3) = 10 Bedside clock 5 x 24 (Note 4) = 120 Total bedroom load 380 Laundry Washing Machine 250 x 1 = 250 Iron 900 x 0.2 = 180 Total laundry load 430 Workshop Power tools 1500 x 0.1 (Note 5) = 150 Other Phones, toys, vacuum, tools etc. 1000 x 1 = 1000 Total household load (note 6) 4975 Factored daily load (4945 ÷ 0.7) (Note 6) 7094

If you are contemplating a solar design of these proportions or larger you really should plan using AS 4509.2 - 2002. In the book "Renewable Energy" "Design, installation and use for home owners" planning using AS 4509 is explained in detail as the standard is quite comprehensive and was written by some pretty clued up people!