solar panel orientation on the equator???

System · April 2009

Can anyone give me input on what would be the best orientation (North, South, East, West or ?) for a fixed mount photo-voltaic solar panel located directly on the equator? I realize flat would be best for max power, but I need to have at least 15 deg. angle so it self cleans in the rain.

Thanks!

niel · April 2009

Re: solar panel orientation on the equator???

for only 1 position you will have to decide if slightly west or slightly east would work best for you. maybe more rain occurs during the evening or morning hours making the opposite the best direction than those of the most rains. it would also be good to have it at at least 2 angles and adjust it twice a day manually or have some kind of tracker for it.

mike95490 · April 2009

Re: solar panel orientation on the equator???

For grid-tie, check your local conditions, as to which is most prevalent, AM fog, or afternoon clouds.

For battery, aim east for best production shortly after dawn, when batteries are lowest, and can accept the most charge, as light becomes less favorable, and charge current is less, you won't be ramping up to full solar power, as the charge controller is throttling back when the batteries reach 80%

BB. · April 2009

Re: solar panel orientation on the equator???

If you can make it an adjustable mount, you could tilt your panel 15 degrees north for six months and south for 6 months of the year.

Regarding facing east or west--probably your local conditions will suggest the "optimum" position (face east if you have afternoon thunderstorms, face west if you have morning fog, etc.).

You can look at the PV Watts program and "play" with the various angles and see how changing the tilt will affect you throughout the year. Note the PV watts program also takes average weather conditions (and cloud cover) into account too.

Where do you want to install the system?

-Bill

icarus · April 2009

Re: solar panel orientation on the equator???

mike90045 wrote: »

For grid-tie, check your local conditions, as to which is most prevalent, AM fog, or afternoon clouds.

For battery, aim east for best production shortly after dawn, when batteries are lowest, and can accept the most charge, as light becomes less favorable, and charge current is less, you won't be ramping up to full solar power, as the charge controller is throttling back when the batteries reach 80%

Mike,

You make a great point that I had never thought about. My first system faced straight south and performed fine. When I built my new place,, I was forced by the topography to orient my array(s) almost 45 degrees east of south,,, say 135. I lamented that fact, plus the fact that they lost their sun quite early in the afternoon,,~3.pm depending on the time of year. On the other hand,, they get full sun a few minutes after sunrise,, and with reflection off the water/ice they come to full output ~1 hour after sun rise,,, as soon as the sun gets higher than any horizon haze layer.

I began to notice that the controller began to dial down long before noon, and on a good sun day the controller goes to float long before the sun goes off the panels. Because the panels can put out full output earlier it allows the controller to work more efficiency.

I do control my loads so that I maximize the loads during the time the controller dials down into absorb. The controller plugs away putting 5 amps into the batteries, while I plug in the lap tops, pump water, run the soldering iron, charge the drill batteries, anything I need to do while the sun is out and the batteries nearly full.

Tony

Solar Guppy · April 2009

Re: solar panel orientation on the equator???

Here in Florida, I have arrays both south-south east and south-south west, the ones facing south-south east out-perform the west ones close to 40% in the rainy season.

Two reasons, the roof is much cooler in the AM and the rains start clouding up the sky @ noon

I had the local Lakeland Electric guys snooping around last week ( they often show up unannounced to show off my PV systems ) with a few Sun-Edison people who are building a 24 MegaWatt Press Release Here PV system here.

You should have seen there eyes when I told them I have a few year data to backup this claim, I suggested they point the arrays due East for the above reasons and ignore the Electric Company who wants due west for the afternoon loads ... It was a chance meeting ... go figure

Cariboocoot · April 2009

Re: solar panel orientation on the equator???

I plan to add panels on my porch roof for exactly this reason. the array on the main roof may be aimed "solar south" but the sun doesn't actually hit it full-on until 10:00 AM! The porch roof will be flood with light a good two hours earlier. Since batteries are lowest in the morning after night's discharge it just makes sense to start charging asap each day. Also, if it turns out you don't have much sun that day you can decide to run/not run generator or loads. Nobody wants to run their gen at night!

Not sure if I should use MPPT on this second array or not, though. It'll be 350 watts, not 'prime orientation' and no seasonal adjustable mount due to layout limitations.

solar panel orientation on the equator???

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