Earlier this year we bought a 10' X 20" storage building and had it delivered to the backyard. The storage building is great - I'm slowly moving things from my garage to the building, I'm doing this slowly because at the end of the day I don't want everything thrown in the building - I want some organization.
One problem with the building is long before it gets completely dark outside it's so dark inside that I can't see anything. It's cost prohibitive to run power to the building so I decided to do the next best thing - solar powered lighting. For an application like this you really don't need a lot - you need to collect enough solar energy to turn on the lights maybe 15 minutes when you need them? But you also need enough energy to carry over cloudy days.
Also, my direct view of the sun is limited from the roof of my storage building by trees so I figure I'll get an hour or two of good strong sunlight a day. This meant that I probably could not get away with a small 15 watt solar panel.
I ended up buying a Harbor Freight 45 Watt solar panel kit and you can find my full write-up of this kit in this instructable.
Step 1: Install the Solar Panels
Installing the solar panels is pretty straight foreword. Because of the type of roof on my building I could just mount the panels with some outdoor rated screws. I was careful to mount one side of the panel through one of the ridges of the roofing and this placed the other side of the panel just inside a ridge.
Before anyone comments about the mounting angle I already know that these are not mounted at the ideal mounting angle for solar energy. But I'm not concerned about harvesting the maximum energy from the sun, I'm just using solar energy to light the inside of my storage building.
Step 2: Getting Power Inside the Building
To get power inside the building I drilled a couple of holes under the eaves then I fished the wires through. I'll pick up some silicone calk for the holes the next time I'm at LOWES.
Step 3: Hanging the Lights
This kit came with a couple of nice 5 Watt florescent lights, each with its own 16 foot power cable and switch. I'll wire both to a switch near the door but for now I'll use the in-line switches that came with the lights to turn them on & off.
I mounted one in each end of my building.
I used plastic staples to hang the wiring, available just about anywhere that carries minimal wiring supplies - I bought this pack at Wally-World for less than $2.00.
Step 4: Final Wiring
For final wiring I cleared off some shelf space for the controller and battery then I ran all the wiring to the controller.
I could have placed the battery on the shelf behind the controller but I wanted the battery out front so that I could easily remove the cell caps and check the electrolyte (water) levels.
In the last picture you can see the two black switches for the two florescent lights.
Step 5: End Result
You can see the solar cells mounted to the roof of my building.I'll know tomorrow after a full day's charging how well the lights work. But I suspect that my old marine battery is too far gone and I'll need to replace it.
If I decided to get really crazy with solar power I could mount 10 more panels to this side of my roof for a total of 195 watts!!! But what would I use it for?
You can find my full write-up of the solar panel kit I installed in this instructable.
Step 6: 09/09/2014 Update
I took a few pictures tonight. The lights are not as bright as my cellphone camera makes them out to be but there is plenty of light from the two florescent lights to see everything inside the storage building.
Also, I looked up the amount of sun available in North Alabama and the average sun hours / day here is 4.43. This number means that throughout the year the sun is shining bright for an average of 4.43 hours a day. This is an important number because it tells you how much sunlight you have to work with.
For example, an average of 4.43 hours a day X 45 watts = an average of about 199 Watt hours a day (4.43 X 45 = 199.35). But that's what the solar panels can produce, then you loose some charging the batteries, etc., and that total loss is probably 30%. This means that long term I can count on 139 watt hours a day (199 Watt hours X 70%).
The two lights together consume 10 watts and "in theory" I could run them almost 14 hours a day off solar power (139 watt hours / 10 watt load).