What type of solar kit do I need to run my grow lights?
A: For most people, the main purpose of going solar is to offset the cost of electricity. However, solar power systems come in two general types, grid-tied and off-grid. This is generally one of the first decisions to make when it comes to solar panel installation.
Grid-tied means that the solar panels are directly tied to the conventional power grid and may provide some or all of your power needs. When unused power is created by your solar panels it is automatically delivered to the grid, earning you credits on your power bill.
Off-grid systems are not connected to the conventional power grid and operate independent of your local power company, and requires that 100 percent of your power comes from your system. Also, unused power must be stored in a battery bank until it can be used at a later time. A truly off-grid system will greatly increase the cost per watt of your solar system and also cost more to maintain over time.
I will assume you are most interested in a grid-tied system. Because of the sensitive nature of the equipment, I would recommend having a licensed electrician pull four circuits from your supply of power. Subpanel No.1 will be for the eight lighting fixtures. Each double-ended fixture is capable of 1,150 watts, so we will estimate maximum power consumption at 9,200 watts. At 240V the total draw is approximately 38.3 amps (38.3A). For safety and load ratings I always add 20 percent which makes the correct choice for Subpanel No. 1 a 50A double pole 240V breaker.
Subpanel No. 2 will be for the five-ton commercial grade A/C which will use about 32A or less at 240V, so that makes the correct choice for Subpanel 2 a 40A double pole 240V breaker.
Subpanel No. 3 is for the commercial-grade 205-pint dehumidifier that will require a dedicated 120V 20-amp circuit with a NEMA 5-20 plug. Lastly, I would have your electrician pull a final 120V 15-amp circuit for all of your additional fans and accessories.
The total wattage of the major appliances is around 18,325 watts. Assuming all the major appliances are running at maximum for 18 hours a day, that is approximately 330-kilowatt hours (kWh) per day or 10,030 kWh per month. However, although the lights will operate for 18 hours a day continually, the A/C and the dehumidifier will not, so your actual consumption will be less.
Because of the complexity when it comes to selecting the right size solar system, I would recommend you to consult a local company to determine the number of solar panels you will need. Local factors such as geographic location, weather, positioning, and line of sight blockages in your horizon all play a factor into how many kilowatt hours you can produce per day. Also, local laws, permits, and regulations will apply, which makes consulting a local solar expert worth the time and money to ensure a smooth purchase and installation.
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