Simple solar light system

Question

I've been looking for a simple solar powered lighting system for a carport I just built. I bought these without realizing how small they are: 2 Pack Solar Lights Outdoor. Unfortunately they look pitifully small on my timber-frame carport. I've found some larger ones, but still not really large enough for my taste.

What I really would like to do is to buy large regular light figures such as 1-Light Matte Black Barn Light Pendant. Would prefer at least 4 of these lights, but maybe more.

Wire those in (and put in a light sensor). Then put in 12v bulbs with something like 12V E26 Light Bulb A19

And then finally hook up to a solar panel system. I have a 200W setup I put on another building, but it's got the full on charge controller and a VMax battery. I was hoping for something a little less complicated. Everything in the carport is exposed, so there's no place to hide the components either aesthetically or from the elements. And I didn't really want to spend that much money just for some simple lights.

I guess ideally I'd like a solar panel with charge controller and battery built in, that puts out 12v and that I could mount to the roofing if they make such a thing. I'm also thinking about a 12v solar battery charger and then in-line a lipo or lithium ion battery. Any suggestions beyond that?

Edit: For more info on carport

Here is what the carport looks like, minus the roofing: Link to carport Design.

I've been thinking some more about the problem and I think I could stick a small waterproof battery box (or toolbox) near the rear of the carport up on the tie beam next to the king post. For those wondering, the tie beam is the beam that runs from side to side. The king post is the one running from the middle of the tie beam up to the ridge beam (the uppermost beam that the rafters sit on). I think with the right size box I could put a small battery (I'm figuring 35Ah) and I have a leftover MPPT controller that I think I can put in the box as well. Then just get a 100w panel. That should solve my problems, but I'm still open to other ideas.

Answer 1

Solar and complicated go hand in hand. Actually power generation is generally complicated. One of the things you buy from the utility is someone else taking care of complicated.

Be careful to distinguish power (watts) from energy (watt-hours)

A 200 watt panel will typically generate 250-300 kWh/year, or somewhere around 0.6 kWh/day. At our latitude (54° N) there is about a 2:1 difference between winter and summer. So that same unit will generate about 1 kWh/day in summer and .2 kWh/day in winter. If I orient my panel vertically that winter number is closer to 0.3

A 100 Amp hour batter at nominal 12v is about 1.2 kWh. This would hold 4 days output in winter from your panel, or 2 days in summer. This is a Group 31 sized battery, commonly used for electric trolling motors. So basically your car battery, but with internal strucutres for deep cycling instead of maximum current. It's Can$175 this week.

Now, for winter you have something like a quarter kWh to work with. 250 watt-hours. A typical LED edison base light is 7W which has the illumination of a 60 w tungsten bulb. Right now, it's dark enough for the streetlights by 5 p.m. and they don't go off until 7 a.m. 14 hours. 7w * 14 hours = 98 amp hours. You can run two bulbs all night.

Still seems kind of feeble.

Ok. Lets put a timer on it. Goes on at dusk off at midnight. Now you can run 4 bulbs.

Different approach: Lets run a few 1 w bulbs so it's dimly lit, but put in a motion detector that will run a pair of 25w floods for 6 minutes when anything taller than a racoon wanders into the detector's field of view.

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Hiding things:

Look into 'racetrack' wiring. These are channels that look similar to chair rails that come in two parts: The base is about 2" wide and half an inch deep. The top is a lid that clips onto the base.

If you have the ubiquitous vinyl siding there is a cute tool at your building store to unhook the bottom edge. You can unhook a strip, tack your wiring to the sheathing, then reclip the siding. This is a real pain for vertical runs, but is fairly fast for horizontal.