Adding 2 440W bifacial panels to my ground mounted array

 Today I drove down to Greentech to pick up 2 440W bifacial solar panels made by SEG Solar in Texas.  I have made an effort to use almost exclusively US mad panels.  I used my trailer to pick them up and they fork lifted them on with a pallet that I was later able to cut up for firewood to heat my workshop. This winter was unusually cold and I almost ran out of firewood so this is a nice freebie!

The panels cost me a total of $417.78 (.45/Watt before taxes), then I stopped by my local metal supplier and spent about $80 on aluminum angle for the mounts.  I will be staking down the bottom rail of the mounts with big tent pegs.  Last fall we had a wind storm that blew them all down - face down.  No panels were damaged other than some minor dents in the frames, but I don't want that to happen again!

New panels on far left

new panels on far right

I now have a total of 46 solar panels on my property! The 4 new 440W panels are wired in series/parallel to yield 60V at about 26Amps which works best with the 2kW inverter I used for these 4 panels.  I used about 20ft of 6 gauge wire from the array to the inverter in the basement.  The bifacial panels are 22.53% efficient which is really good and the back side can contribute up to 15% from reflected snow.

 inverters

I now have this array split between 2 inverters.  The original 1kW unit was maxed out with the original 6 panels, so I added a 2kW inverter (shown on left below).  So the 4 big panels (about 1760W) are on that one with a 20ft. run of 4 gauge wire, and the 4 small 195W panels are on the smaller 1kW inverter.   

The 2kW unit puts out 240V which is wired right into the breaker box on the left.  The smaller 1kW unit has a power cord that simply plugs into an outlet on the wall below.  Mounted above them are circuit breakers that serve as disconnects for servicing the arrays.

Wiring diagram for my ground mounted array
 

My goal is to move toward zero electric bills in the winter.  With 2 heat pumps working hard in the Maine winters, and my Chevy Bolt EV also using more power in the winter, my bills are running over $250/month in January and February!