Super steep paneling in the frozen north?

softdown

This is one of the most popular subjects here and for good reason. Your choice of panel angling has a significant bearing:

1) On ability to shed snow.

2) Maximize harvest during the shorter, darker days of winter vs harvesting more during the super long days of summer.

My place for example though it is not truly far north. Lat. 37 means the most annual energy is harvested with a 32 degree panel tilt - according to conventional wisdom. My readings have indicated that 52 degrees will maximize winter harvest and 22 degrees will maximize summer harvest.

If you run a lot of summer time a/c the decision is probably easy for obvious reasons.

I chose a 45 degree panel tilt with a 37 degree latitude. Here are the results:

Snow and ice is almost always shed by 11am. I don't normally get a lot of snow though, this is a dry environ.

The panels start showing energy production about 7am during the winter. Energy production starts around 6:30am during the summer time due to the Daylight Savings clock shift and panels that are geared for the winter. Of course they produce for more hours during the summer.

Board members are pretty universal in agreeing that over paneling is more effective than solar tracking. Also that adjustable mounts are a pain and a weak link that are always discouraged after some experience.

I believe I have read accounts of northern users who wish they had chosen a steeper angle. Can't recall any who wish they had opted for a milder angle.

This gets discussed pretty frequently here.

BB.

Another option is "virtual" tracking... Face one set South East, and another South West, and you have "more actual hours" of solar harvest... Very nice for Lead Acid type batteries which need many hours in absorb to fully recharge (something like 2-6 hours, depending on depth of discharge).

You can use PVWatts to model various configurations/angles/directions for the arrays and download into a spread sheet (hour by hour, 365 days a year) for the details:

https://pvwatts.nrel.gov/pvwatts.php

-Bill

MichaelK

For my particular situation, my solution is solar tracking, and over paneling.  If I want to start my wellpump at 7:30 in the morning, I can rotate all the panels eastward.  In the afternoon, it's westward.  For run of the mill days when I'm not pumping water, I do as Bill does and have some panels pointed eastwards and others westwards.  It keeps the panels from exceeding the controller's amp limit.

706jim

My "virtual tracking array" works wonderfully. Easily covers my 5Kw-hr average daily usage. Panels at 60 degrees from horizontal.

softdown

60 degrees from horizontal is very steep. Would some call it 60 degrees from vertical?

My 45 degree panels at 37N work better during the winter time but there are many more hours with no harvest available.

For me July is the peak month for AM starting voltage due to battery temperature. Woke up to 50.3 in spite of running two additional freezers and a small overnight fan. On a quest for battery longevity - I think most of us are.