My Start With Solar Panels

Phase 1

 

I've been intrigued with solar panels for years.  They have been very expensive, and typically geared towards complete home systems.  Very little information or kits available for the general public.  So where to start?  Harbor Freight now offers a 45 Watt kit for $179 on sale.  The kit includes three 15 Watt solar panels, a simple frame, a basic charge controller, and two 5 Watt compact fluorescent lights.  You need only supply a storage battery to have a functional system.

Our local Harbor Freight store has these kits available, but you have to ask for them.  They are stored in the warehouse, not in the store area.

 

 

The kit included two 5 Watt fluorescent bulbs, which run on 12VDC.

Just as a demonstration, I connected everything up without a battery.  Even with the sun almost set, it still provided enough energy to illuminate the fluorescent bulb.

The included solar controller is really cheesy.  Almost nothing inside the box.  Many reports of failures of these controllers, so mine instantly went onto the shelf as an emergency backup.

 

I built a frame to hold the panels securely on my roof.

 

So can you run your house from this setup, well no.  But you can run these lights for hours, with no other source of power.  You can also recharge your cell phone, batteries for flashlights & radios, and even run a small TV for an hour or two.  During a hurricane (or other) outage, this equipment can be very beneficial.

The panels are rated at 15 Watts each, or 45 Watts total.  But in actual testing, these panels produce about 0.7 Amps per panel, or 2.1 Amps for the array.  All panels are derated to ~ 70%.  Part of this may be due to how the rating is achieved.  With no load, these panels put out 22-23 Volts.  A short circuit test of the panel produces about 0.7 Amps.  22 V x 0.7 A = 15.4 Watts. 

In Florida, I have about 5 hours of peak sunlight per day.  This is the point at which the panels should be producing their rated output, depending on weather conditions (clouds, rain, etc).  So 5 hours x 2.1 Amps (entire array) = 10.5 Amps per day, or 126 Watt/hrs per day (10.5A x 12V).  The included lights are rated at 5 Watts each, both running is 10 Watts.  126 Watt hrs / 10 Watts = 12.6 hours.  These numbers are calculated, not accounting for all the losses.  Nevertheless, that'll keep two rooms illuminated all night.  In 2004, two back to back hurricanes knocked out local power for several weeks.

The best part is this system is expandable.  Add more panels, more batteries, a better charge controller, and you'll eventually be able to remove portions or your home from the grid.

 

How I Built A Frame For The Panels

Phase 2, Add Three 15 Watt Northern Tool Panels

 

 

 


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Last updated 08/04/08    All rights reserved.