Photo voltaic

4.8 KW Residential Solar Photovoltaic Overview

The big project for 2007 and 2008 is getting solar photovoltaic on the roof.  We’re doing what we can to reduce our carbon footprint and fight global warming.  I installed my own 4.8 KW (DC) system consisting of 24 200W modules and an SMA Sunny Boy 4000US inverter.

My upper roof showing 9 of my total 24 photovoltaic panels


(I joined Bell Labs in 1980, years after they invented the photovoltaic cell, first called the solar battery, but I still get to say I worked for the company that invented them.)

If you are interested in your own photovoltaic system, my analysis may help you decide what size might be appropriate for you, how much it might cost, and how it would affect your electric utility bill.  If you want to install your own system, a word of caution: some of the highlights of installing your own system include dealing with truck freight companies, climbing ladders, spending lots of time on your roof and drilling holes in it, installing wiring in accordance with national and local codes, working with live wires with 600V DC (if the sun is shining, the DC side of your PV is ON) and installing new circuits into your main utility service panel.  If all that sounds like fun, you may want to do some of your own work.

Try reading all the articles by John Wiles at NM State University by clicking on agree and then click on to Code Corner.  While not written for the do-it-yourselfer, this site provides useful information on wiring, grounding, and recent code changes.  It is a GREAT source of information and can help the weekend wiring warrior gain the confidence they need to tackle a PV project.

Product Recommendations

I’m happy with my photovoltaic modules, but there are a lot of PV manufactures and the modules are becoming a commodity.  Choose a reputable supplier who will stand behind what they sell.  And absolutely be sure the equipment is UL listed.  This is especially an issue where companies all over the world are manufacturing and introducing new module designs daily.
I highly recommend my Sunny Boy SMA 4000US inverter.  SMA makes a great product; they have very good technical support, and they have a good warranty replacement program.

Supplier Recommendations

I purchased my inverter and photovoltaic modules from David at and I highly recommend them.  There selection is somewhat limited to just a few brands, but they deliver products with great price/performance and the customer service is prompt and helpful.  And they are an AEE Solar reseller so you can get anything from the AEE Solar catalog though them.

I got my racking and some misc stuff from Justin at DC Power Systems.  They are a full service supplier and can help you with all things solar.  Justin took the time to look at my rack plan and optimize my order.  By choosing some different combinations of sizes he saved me several hundred dollars.  That was service over and beyond what I expected.

All In One Design Document

If you prefer to read a single design document with all the information, here it is.  And here’s a very brief slide show of my experiences.

Otherwise, visit these specific discussions.