Solar Panel Calculator

As a general rule, you will need 10 watts of power for each output joule of your fence energizer. For example: 3-joule energizer = 30 watt solar panel. Use the calculations below to determine wattage needed for your energizer and location.

Step 1: Calculate the Ah per day needed
Determine wattage of the unit.
Battery voltage x Energizer amps = Watts
12v x .29A = 3.48W
Watt hours = 3.48W x 24 hours = 83.52Wh
Determine Amperage Hours
A= W/V
Ah = 83.52WHr/12V = 6.96 Ah per day

Step 2: Determine peak sun hours for your location.
For example, average sunlight near Blairsville, PA = 3.68

Step 3: Calculate which solar panel will provide the Ah per day you need.

Now divide the Ah that you need (from Step #1) by the number of Peak Sun Hours per day

Example: 6.96Ah/ 3.68Hr = 1.891A

This means that a panel that produces 1.9A is what you want. Determine Panel Size:

A = Watt/Volt
Watt = Volt x Amps
? = 12V x 1.9A

=22.8 Watts - Always add 20% to take account the real world conditions.
=27.36 Watt Panel - Round to 30 Watt Panel.

Battery Recommendations:
Deep cycle batteries are recommended for solar powered fence systems. These batteries are designed to be discharged over a long period of time (100 hrs.) and recharged hundreds or thousands of times. To maximize battery life, deep cycle batteries should not be discharged beyond 40-50% of their capacity. For example: A 3-joule solar fence energizer would work without sunlight for 8.6 days and only use half the capacity of the battery.