Suitability

[Square Peg]

I live in SW Michigan. Not a lot of sunny days and to top it off my lot is narrow surrounded by large trees. Is there an economically feasible way to determine if I have enough sunlight to power a 400 watt array before investing time and money in a futile effort?

 

[chrisski]

Recommend using a solar calculator like PV Watts or one such as in my signature block.

I have no idea how much Michigan produces, but my guess is 400 watts or less in the winter and perhaps 2000 watts in the summer, not adjusted for shade. Any shading of the panels will make for negligible production.

This may be OK for some uses, but you’d really need to watch your power. You need to do a power audit And figure your real power needs.

Those calculators don’t include shade, and from there its a guessing game. The calculator in my signature block she’s how higy the sun gets in a certain part of the season, and based off how high the trees are, you can take a percentage off production. Much more loss in the winter than summer.

 

[Nobodybusiness]

You sure you mean 400 watt array?

Usually 1 panel is 400 watts.

Do you have spot in your yard or roof that receives direct sunlight most of the day?

You will get production at your house.

How much depends on how many panels you have, what month it is and how long your panels are in the sun.

It’s not futile at all but you have to do some calculations to see if it makes Financial sense unless you don’t care what it cost.

You might need at little bigger array so you can have required production in the winter then have excess in the summer.

 

[Square Peg]

You sure you mean 400 watt array?

Usually 1 panel is 400 watts.

Do you have spot in your yard or roof that receives direct sunlight most of the day?

You will get production at your house.

How much depends on how many panels you have, what month it is and how long your panels are in the sun.

It’s not futile at all but you have to do some calculations to see if it makes Financial sense unless you don’t care what it cost.

You might need at little bigger array so you can have required production in the winter then have excess in the summer.

Yup 400 Watts. I was looking at a kit from Renogy (pretty simple plug & play; fits my skill level and budget). My plan was to run a garage door opener (5 amp draw) and three lights.

 

[chrisski]

Yup 400 Watts. I was looking at a kit from Renogy (pretty simple plug & play; fits my skill level and budget). My plan was to run a garage door opener (5 amp draw) and three lights.

I’m assuming the 5 amp draw is at 120 volts, so that will require about 60 amps of power from a 12 volt pack. Might need a 1500 watt inverter to run the garage door opener with the surge.

With this system, its going to cost you more money than you will every save on electricity.

Batteries are another thing. One but probably two 100 ah lithiums may cover this. not so much for watt hours, but to cover the inverter and the surge. With lead acid, would be cheaper, but the problem would be charging the battery with enough power To keep it healthy.

When I started, I found kits extremely misleading and opted to build mone from individual components.

 

[Mattb4]

In the area you are thinking of placing your panels simply put up something to check during the day for amount of shading. White plastic sheeting cut to the size of panels would work and stapled to a couple of posts if ground mount. Your most productive sun hours are 10am till 4pm. If you have any shading during those hours the setup likely will not work out for you.

 

[Square Peg]

i was more interested in discussing panel placement however since you ask: the opener that I’m considering is a Chamberlain RJO70 with 12v battery backup. I would prefer a unit that runs solely on 12 volt DC but have not been able to find one. I’m looking at a solar kit with inverter because I am not comfortable that I have the technical skill to spec a component system. I have seen a 20 watt panel run a 120v opener with battery back up. I understand that there will be 2x conversion loss and a need for overcharge protection along with many unforeseen issues. It seems to me that the place to start was to find out if I have enough sun light to start with. I’m going to try the mock up suggested earlier as soon as it stops raining