If all panels are facing East and not North how much power am I losing in a day?

Have a play on this site.

It also depends on tilt, and your own location.

http://www.solarelectricityhandbook.com/solar-irradiance.html

41 minutes ago, Mistral said:

If all panels are facing East and not North how much power am I losing in a day?

But, this is not the whole story, if you are not permitted to export power, and your batteries are charged, your production will equal your loads.

In other words, if you had no loads that day with charged batteries, you would lose all that day's power regardless of panel direction.

The ideal panel configuration is one where your panel layout matches your load profile for as long as possible during the day, with a bit more to make sure your batteries are charged by days end. Probably a blend of east, west and North panels.

You can also manipulate your load profile to make this fit better.

This is in contrast, to say this scenario:

Your meter went backwards ( heaven forbid!), you could treat the grid like a huge battery, and put the excess in whenever you had it and take it out whenever you needed it.

Then the emphasis would be on maximum production and you'd want optimum north panels.

In reality an asymmetrical import/export tarriff, would skew this to be some blend of both the above, probably still weighted to the former.

Edited April 28, 20197 yr by phil.g00

Thanks for these good points.

I have used the handbook but wondered in general terms if this is a bad idea.

I have a sloping flat (corrugated) roof which may cause problems with installing panels and facing

East looks like the best solution. The roof is in full sun all day.

Where possible I would aim at using the grid at night to optimize the life of the batteries.

Edited April 29, 20197 yr by Mistral

1 minute ago, Mistral said:

I have a sloping flat (corrugated) roof which may cause problems with installing panels and facing

East looks like the best solution. The roof is in full sun all day

Yes, then of course there are the practical realities of any situation.

Whilst,  I have decided to use panel directionality to spread production throughout the day, I have however foregone the notion of using optimal panel tilt.

I have decided, that it is far more practical (and aesthetically pleasing), to go with the respective roof angles, instead of building tilted frames.

I'll adjust the number of panels in each array to compensate.

 

That is a good tip!

Was planning to use aluminium tilted frames which are expensive.

Edited April 29, 20197 yr by Mistral

27 minutes ago, Mistral said:

That is a good tip!

Was planning to use aluminium tilted frames which are expensive.

I have actually taken frames down, because getting rid of the shade they cast allowed me to install far more panels.

Even though the replacement panels are now sub-optimal in both tilt and direction, it is a far nicer looking installation, it allowed me to install considerably more panels on the same roof area and subsequently makes more power for longer during the day.

Flatter panels are also more productive per panel when it's overcast, which makes a difference when you have twice as many panels.

Edited April 29, 20197 yr by phil.g00

These are the frames, ( in my inherited installation) that I removed. I could fit all these panels back on the roof again, and another 8kwp besides that and there is still space for at least another 8kWp.

5 hours ago, phil.g00 said:

These are the frames, ( in my inherited installation) that I removed.

Holy smokes!!! I'm no engineer but living in Cpt ... "gone with the wind" comes to mind.

The strain on the roof trusses with a new norm storm ... no thank you.

2 minutes ago, The Terrible Triplett said:

Holy smokes!!! I'm no engineer but living in Cpt ... "gone with the wind" comes to mind.

Oddly, after a few years worth of storms they never moved an inch and it was only their own weight holding them down.

I did have my concerns though, so I roped them together on the year previous to their eventual removal.

No concern about the roof trusses with the weight of the additional new panels, because they are recycled steel trusses that are about twice as close together as spec. I actually don't think there would have been an issue at spec spacing either.

Now the structure at the back of which the corner is just showing, that's something else. It's an 8m by 8m array on an 11m tower, (at the high side).

That's built so that the town will capsize before it blows away.  It's a monster though, I couldn't have afforded to build it, if I hadn't of bought some scrap power pylons 25 years ago.

You can see why I'm fussy about lightening protection, this being in the Drakensberg.

13 hours ago, phil.g00 said:

Yes, then of course there are the practical realities of any situation.

Whilst,  I have decided to use panel directionality to spread production throughout the day, I have however foregone the notion of using optimal panel tilt.

I have decided, that it is far more practical (and aesthetically pleasing), to go with the respective roof angles, instead of building tilted frames.

I'll adjust the number of panels in each array to compensate.

 

I cant recall which tool i used, but for me it was more important to have fixed amount of kwh from my panels no matter what. 

So i did calculations on each month for each angle and settled on North @ 22deg, this way i know exactly what to expect from my panels, regardless of season.

@stoic, That is a very interesting power requirement.

If I had say a fixed amount water to heat daily, the resistive element wouldn’t care if it got its energy over two hours or five. So long as it got “X” kWh/ day, I would opt for a similar configuration.

This configuration does require a load that will use whatever you have, whenever you have it. It isn’t the typical load profile of most households.

 

16 hours ago, phil.g00 said:

@stoic, That is a very interesting power requirement.

If I had say a fixed amount water to heat daily, the resistive element wouldn’t care if it got its energy over two hours or five. So long as it got “X” kWh/ day, I would opt for a similar configuration.

This configuration does require a load that will use whatever you have, whenever you have it. It isn’t the typical load profile of most households.

 

We knew going solar would cause us to change habits, and my wife is BIG on routines, so making sure she can get into a routine and be able to follow that no matter what time of the year was very important  

Routines are essential when going solar!