Sunday, September 30, 2012

So much more fun

Will be enjoying the fruit of my labors soon as I finish up the electrical wiring and lighting.
Trenching in the 3/4" PVC  from the PV to the bridge.

The 14 gauge wire carrying the 120 volt AC from the 600 watt inverter will flow through a 15 amp fuse, shut-off switch and to three different, individually controlled light strings. One string of four 60 watt CFL's indirectly lighting the outside of one truss. A second string of four more 60 watt CFL's down the center of the bridge on the inside of the bridge. Third, six strings of LED lights covering the gable ends and back top chord inside.

The pictures with my digital camera don't do justice to the lighting but you can get the idea.

Until you come and see for yourself the 4 timber framed covered bridges in Lafayette county, Wisconsin you'll just have to take my word for it they are pretty cool!

On the solar PV system electrical technical side:
- Input
Six individual photovoltaic (PV) panel for a total of 350 watts, 12 Vdc, of PV capable of generating 11 amps of current input to two 6 volt deep cycle batteries.  In there present location by the bridge on a sunny day they are capable of supplying the batteries with 25 amp hours (Ah) of energy from the sun.

- Demand (DC to AC includes inverter)
Four 60 watt CFL's draw 6.2 amps for a load on the batteries of 6.2 amps per hour (Ah).
Six strings of LED lights draw 4.8 amps for a load on the batteries of 4.8 Ah.

The challenge over the next year will be to determine the lights to be used and the time to program the 12 volt dc timer to turn the system on and off so as not to drain the batteries. Should be a fun and educational experience.

Now on to the next project. A nice oak bench for my old neighbor Bink.

Friday, September 21, 2012

Let there be light...

Time to add a little power to the bridge to brighten it up at night. I had a 350 watt, 12 volt PV battery system that I built several years ago for a high school class on renewable energy I was teaching just sitting around. The class project system was featured in Home Power magazine Dec '99/Jan 2000 Issue #74 pages 24-30. All the system details can be found on line in this article.

Powering up the bridge with lights at night would be a good use for the system. One would think this  system is way over kill for just four 16 watt CFL's but we'll see.  Time will tell. There will be some shading of the panels because of the location but the excess PV capacity should more than make up for it. I hope.

Things tend to get messy pretty quick with all the components and wiring that goes into a battery PV system as you can see below. Two 6volt deep cycle batteries, battery monitor, charge controller, fuse box, inverter and lights. For new construction component placement comes first and then the wire cut and routed. On this recycle project I found it best to just connect the components with existing wire lengths and then place them where they fit.

And the final results were efficient and pleasantly surprising.

It was a pretty sunny day yesterday so I collected some data on the new system. In a nut shell - From 1 to 3 pm the PV generated 7.2 Amp hours of power to store in the batteries. I turned on the four CFL's for one hour and they (along with the inverter) consumed 10.1 Amp hours from the batteries. Hopefully I can count on 2 - 3 more hours of morning sun. In the meanwhile I'll be doing more data collection and testing to report in a later post.

Monday, September 3, 2012

Oh Wow!

After considerable thought I have decided to go with  a metal roof. The metal roof will be less costly, require less labor and perform better in my wooded location. I had enough 2x4 material on hand for the perlins so it was a go.

 First order of business was to close in the gable ends. In this way I could cut the notches where the perlins would extend for the rake overhang to fit nicely. Note: if you look down the peg line in the top right chord you can see the camber of the truss.


Ramps and a floor.

Ready for steel.

Starting in the center and working toward the ends because of the camber in the trusses.

One fine looking bridge if I do say so myself.

 Portal view at night.

Even installed some lights to make the bridge glow at night. These will be run by some solar panels from an old system that I have.  Like I told my students, "Crossing a bridge in your future will be a bit easier after you have built one or two."