North facing Panels

[MetricAmerica]

Had a system installed with two inverters and 42 panels. Some were placed on south roof and some were placed on the North roof. The system is rated 11 KW D.C. with two inverters.

I live in Southern California and currently the 23 Southern roof panels in full sun without clouds generate around 3700 watts during peak hours . It has a 6 KW inverter.

The North Roof is generating about 800 watts with 19 panels (265) under same circumstances.

Well, installer shouldn't have done that, and do not know if you can get any money back, but now you learned of your mistake, all is not lost. I would, if I was you, take those northern panels down, and mount them on a dual axis tracker in your backyard. And you will way ahead in the power making department, perhaps you can even reuse northern rack with hot water panels, granted you will run in same out of sun axis problem, but you don't use hot water like you do electricity....

[ButchDeal]

yep, but no convincing the customer because he is "in the industry" and knows best.
I told him we would not install on the north over the south and if that is what he wants, he should find another installer.

He stated that he thought he spoke to them all and was going to have to do a self install.

[J.P.M.]

In his area the sun will rise just north of due east and set a few degrees north of west.

And as you know, only for half the year in any area north of the equator. Additionally, as I'm sure you know, most any insolation on an array of any orientation at early/late hrs. will be small enough to be ignored anyway.

[rsilvers]

One of those "every situation is different, and most of'm ain't mine" types of situation. Just seems quite unusual overall to the eye attached to an informed brain is all.

An SREC2 is worth about $250. The electricity is worth about $230 per megawatt. So even north facing panels making half the power are still as good as south-facing panels in some other states.

So if the logic seems dumb, it is only because the incentives are unusually good (and arguably unfair to non-solar users).

[DanKegel]

Time lapse photography might have been able to do it. I wonder if an old cellphone running a timelapse app might become an important sales tool.

[J.P.M.]

They had two south-facing surfaces covered also. Maybe they were going to stop there, but realized that with the SRECs, also doing the north was better over 10 years than not also doing the north.

So they probably still made a better decision than the dozens of perfect south-facing wide-open roofs I saw today that had no solar at all.

One of those "every situation is different, and most of'm ain't mine" types of situation. Just seems quite unusual overall to the eye attached to an informed brain is all.

[ButchDeal]

If I haven't talked to that guy (I may have - what's his zip ?), I feel like I've talked to a lot of his clones. Some folks have their minds made up and don't want to be confused by facts.

Well I figured out kind of what was going on. his house faces due North and as he mentioned when he pulls out of his garage in the morning he is staring at the sun in the north. In his area the sun will rise just north of due east and set a few degrees north of west.
The problem is that he is at work all day and in between those two points the sun is on an arc swinging towards due South and then west.
so at the lowest points the sun is north of east west line but much of the day the sun is (obviously) south of the east west line....
was not able to convince him even though his south roof was large enough for the full array.

[J.P.M.]

I had extensive conversations with a customer that wanted PV on the north face of his home. He was trying to convince me that the sun was in the north of his home for a significant amount of the year due to his low lat. in San Diego area. I tried to explain things to him and he was quite biligerant that he is in the industry and knows what he is talking about, why are all the installers he talks to trying to tell him what he can clearly see (the sun).
He decided to do a self install.

You can't help everyone.

If I haven't talked to that guy (I may have - what's his zip ?), I feel like I've talked to a lot of his clones. Some folks have their minds made up and don't want to be confused by facts.

[rsilvers]

They had two south-facing surfaces covered also. Maybe they were going to stop there, but realized that with the SRECs, also doing the north was better over 10 years than not also doing the north.

So they probably still made a better decision than the dozens of perfect south-facing wide-open roofs I saw today that had no solar at all.

[ButchDeal]

Looks like the decision making process what went on might not be best described as thinking.

I had extensive conversations with a customer that wanted PV on the north face of his home. He was trying to convince me that the sun was in the north of his home for a significant amount of the year due to his low lat. in San Diego area. I tried to explain things to him and he was quite biligerant that he is in the industry and knows what he is talking about, why are all the installers he talks to trying to tell him what he can clearly see (the sun).
He decided to do a self install.

You can't help everyone.

[J.P.M.]

In the winter the array would likely be shading ITSELF. What were they thinking?

Looks like the decision making process what went on might not be best described as thinking.

[littleharbor]

In the winter the array would likely be shading ITSELF. What were they thinking?

[rsilvers]

From above:

[J.P.M.]

7 degrees was the heading. Angle is 40 degrees.

PVWatts says that the south side will make 2.1x as much power as this side.

That makes a $4.50 per watt system act like a $9.45 per watt system that faces south.

On the PVWatts estimate, pretty much/probably, and the trees will reduce output even more, probably in a higher proportion for the south calc'd roof .

To help me out, the array azimuthal angle is 7 degrees ? 40 deg. is the tilt or elevation angle off horizontal ?

Thanx.

[sensij]

Sorry, misunderstood. Thought the offending panels might be on the car port. Nothing good to say about this one.