Adding 4 solar panels on the ground

Solar arrays on my workshop

 My solar power system consists of 37 solar panels mounted on my workshop building and another 250 W panel mounted on my house facing south.  The original 30 panels were only rated at 175W when I installed them 16 years ago.  Then I added additional panels rated 2 tilting 245 W panels and 6 more 375 W.  The problem is in the last few years I have added heat pumps which draw an enormous amount of power during the winter months and my electric bill shoots up from zero (actually, $42 minimum connection fee charged by my utility for the "privilege" of being connected!) through the summer to over $300 in January and February.

With electric rates increasing dramatically I am looking at options.  In my home I'm shifting back to using a propane heater for my living room because the heat pump is unreasonably expensive to operate and in both buildings I'm using more firewood to offset the use of heat pumps and fossil fuel.

Last winter when my propane automatic standby generator failed I was without power for four days and this was unacceptable so I purchased two solar panels and a battery generator as documented in this recent post.  Then in the spring I decided to use the battery generator as a backup power supply for my 3D printers and stored the solar panels inside my workshop.  I realized this was pointless because I was literally losing money from energy these two panels were not generating.

 

So this October I decided to deploy those two 195W bifacial panels and add a couple more similar panels but they're not bifacial, however monocrystalline panels are much more efficient in low light.  Bifacial panels can generate up to 15% more power from the back especially when there is snow on the ground to reflect light onto the back. 

The panels are facing south and tilted up at a high angle to account for the low winter solar elevation angle. 

Panel specs

 

 

Here's a back view showing the bifacial panels on the right.  These are all made by a company called Eco-worthy who make very high quality and very affordable panels and I bought them on Amazon.

 

 

 

 

 I made my own mounting system using aluminum L extrusions that I riveted together.  This cost me roughly $40 per panel and should hold up well.  The whole mounting system folds up flat so I can take it down and store it should I need to.  Cearly, I will need to shovel snow away from the bottom of these panels in the winter.  But that's no big deal to me.

  

It's fall here in Maine and the time of year where we get very strong winds so I used tent pegs to secure the bottom of the mounting brackets firmly so they won't blow over.

 

 

 

All of my other solar panels are connected to the grid using micro-inverters made by Enphase.  (One micro-inverter for every solar panel).  However over the last 16 years 17 of the 32 original inverters have failed.  These were first generation technology and they have been replacing the failed units under warranty with seventh generation technology, but my warranty has now expired.  My trust in that system has eroded over time and I decided to use a string inverter.  String inverters take multiple solar panels connected in series and/or parallel and convert that to 120 V AC or 240 V AC.

Series-parallel connections

I connected the panels in this configuration as shown above which is the optimal one for best energy performance and the smallest gauge power cable required to feed the solar energy to the inverter.  The inverter wants to see a DC solar input from 22 V to 65 V.  By wiring two panels in series I get approximately 44 V and then by connecting them in parallel I optimize the power delivered to the inverter

I needed a couple of Y adapters in order to connect the two pairs of panels to the main cable that feeds into the inverter. Solar power cables use MC4 connectors which snap together and form a fully weatherproof connection.   These connect to red and black 10gauge wires that go across my yard for about 15 feet where they pass through the wall and down into my basement where the inverter is.

 

  

 
I purchased a weatherproof cable entry cover so I can prevent weather and critters from crawling in to my house.  These are typically used on campers and boats.

Down in the basement, I was able to install the (blue) inverter right next to my breaker panel.  I used more 10 gauge wire than I needed and tucked it up in the ceiling in case I need to move the solar panels.  Power comes out of the inverter at the bottom and that power cord plugs directly into an outlet to back-feed the outlet.

This is a G2 Series Grid Tied Inverter (model SUN-1000G2-M) that I purchased on eBay very affordably.  It is rated for 1000 W and my four solar panels can produce up to a peak of 800 W so I might add two additional panels in the future which shouldn't be a problem for this inverter.

The little blue display above the breaker panel monitors a single 245W solar panel mounted to the south wall of my house.

 

 

The inverter has a very helpful color display screen that shows power being generated and also a chart of Watts versus time. This was taken around 9:00am.

 

 

 

 

 

I connected this AC circuit to my Emporia energy monitor so I can see live data of the energy being generated in real time.

I did a detailed blog post about the Emporia system I installed back in 2021.  It is a very affordable system that I use to monitor 8 circuits in each of my 2 buildings.  I can track energy flowing in BOTH directions - meaning that solar power shows as "negative" energy in the charts and readings.

Replacing old windows in my workshop with new energy efficient ones

 

Before and after

Recently I started seeing ads online for replacement windows.  While my home has high-quality Marvin Windows that are double pane, gas-filled, low E very efficient windows my workshop still has the original barn windows whose only purpose was to let light in.  The photo above shows the original window on the left which is entirely made of wood with single pane glass panels.  So I reached out to three different window installer companies to get quotes.

For context, my workshop was originally an open barn built in the early 1990s - so about 35 years old.  When I purchased it in 2001 I converted it into a super insulated very well sealed building using spray in foam and added fiberglass to create R30 walls and R40 roof.  The cheap wood windows have always been the weak point in this building from an energy standpoint but they are also rotting and falling apart so it was time to replace them.

The first company showed up the next day to give me an estimate and they took measurements of all seven windows, 5 on the ground floor and 2 upstairs.  Their first quote was $12,071!  I was stunned!  This was way outside my budget of around $5000 and I told them so.  So I asked them if they could re-quote the job allowing for me to remove all of the trim indoors and outdoors so they could just remove the old windows and put in new ones.  That quote came to $7242, still outside my budget and a big surprise that they could come down that low.  Honestly it struck me as ethically dubious, but still too much for my money.  But these guys kept working the deal like sleazy used car salesman and finally offered another deal of doing three windows for a "mere" $5169.  At this point I got angry and told them to leave.

So then I started researching replacement windows on Lowe's and Home Depot websites and found a window at Lowe's that is a little smaller than the framed opening in my building but, get this - these windows were only $218, so I immediately bought 4 of them because that's all they had in stock at that time (I need 5 for downstairs and 2 upstairs).  These are very high performing windows - see the spec sheet below:

These specs compare favorably with some of the top-of-the-line windows made by Anderson and Marvin.  The whole window is made from vinyl which will never age badly.  

My first step was to remove all the window trim on the outside which was very hard work since the whole building was constructed with BIG nails.  Removing the trim ended up destroying all that wood which was rotting anyway.  Note that I had installed spray foam between the window frame and the window itself because they were huge air gaps there originally.

 The next step was to install flashing tape.  This is 6 inch wide tape with a reflective surface and extremely adhesive rubber that sticks to the walls very well.  After installing a couple of blocking strips I was able to put the window in quite easily: 

 

I then installed the new window using two screws at the top and two at the bottom per the instructions.  I then put a 2 inch wide strip of flashing tape to bridge the window frame to the building and weatherproof it. 

 

 

 

 

I purchased some PVC exterior trim and installed it.  Again, this stuff will never rot like the old wood windows and it looks really great!  It's surprisingly expensive but worth every penny.  One piece of 1X8" 8 feet long cost about $50 and I ripped it down the middle and used that for each window.  I caulked around the outside edges of the trim and also at the bottom edge of the window where it meets the trim using very high quality GE silicone caulk.
 

 

 

 

 

 

 

On the inside.  I forgot to mention that I had to frame the framed opening down to fit the new windows which were 3 inches shorter and 1 inch narrower than the old ones. So I installed a 2 x 8 at the top and bottom and a piece of 3/4" wood on one side to fill in the original framing.

 

 

 

 

 

I was able to reuse a lot of the interior wood trim and then paint it.  I also purchased some primed 1X3 for the final trim framing.  These windows look a lot nicer than the original crappy wooden ones which were natural wood and looking very sad.

 

 

 

 

 

From an energy efficiency standpoint the original 7 windows were costing me approximately $726 a year in heat loss.  The heat loss through the new windows will be around $147, so I improved the window performance by 500%!  My building is heated primarily with a (self installed MrCool) heat pump that is about 400% efficient.  I back that up with a wood stove when it's very cold outside (meaning below 20°F)  and I have a lot of wood scraps both from the demolition work but also as a woodworker I end up with a large amount of scrap anyway.  I use my wood scraps for kindling and burn about one full cord of hardwood per season.

While it was 4 or 5 hours of hard labor to install these windows, it was worth every penny to do it myself and do it the way I wanted it.  I'm not quite done installing them yet but I think my total cost will be less than $2000.  So in a way I'm paying myself thousands of dollars per hour in labor!

I had some trouble locating windows that would fit the upstairs two windows which are slightly smaller so I emailed the manufacturer (United Window & Door) and asked them if they could make me custom windows.  Their response was immediate and they offered to expedite a custom order for my exact size windows for me once I placed the order through Lowe's.  They also offered to expedite getting one more window for my downstairs.  Great customer service!!

Finally, I stripped out the aluminum side rails from the old windows and took them to a local guy who takes scrap metal for recycling, then I took the old window screen and trim scraps to the dump.