Solar in the Winter?

Most suppliers and users of panels quote between 10 and 25% output in cloudy/ dull conditions,this would seem to fit with the graphs...bearing in mind no tilt and parking position,I have based my system on 10% winter production versus needs ..means a big surplus in summer but no generator in winter(although I have a diesel feeding a100 amp forklift battery charger just in case)the joy of off grid home!! But the same figures should be Bourne in mind with any system.Summer surplus goes to hearing water
 
I was at a place last week, they have 3 off 6.5kW arrays. They were producing between 2750 and 2900 watts each, which I thought was quite impressive. They are angled though.
 
I have 2 150W tilting solar panels on the roof which can be elevated to about 45*.
Also I have a vertical rotating 50W panel that tracks the sun during daylight hours.
The rotating panel is only just finished so I have no idea of its efficiency. Hopefully I'll get a chance to test it this winter and record some data.

IMG_20191031_142521.jpgIMG_20191008_114436.jpg
 
I have 2 150W tilting solar panels on the roof which can be elevated to about 45*.
Also I have a vertical rotating 50W panel that tracks the sun during daylight hours.
The rotating panel is only just finished so I have no idea of its efficiency. Hopefully I'll get a chance to test it this winter and record some data.
Is that another solar panel behind the tilted one? If so, surely that will be in shadow from the front one and so get wiped out?
 
Is that another solar panel behind the tilted one? If so, surely that will be in shadow from the front one and so get wiped out?
The idea is to have only one elevated at one time, the east facing one elevated in the morning the west facing elevated to catch the setting sun. It was the best I could come up with, with the available roof space. It has to be better than a flat panel.
I hope to get some meaningful data of recovered solar energy through my Victron BMV and MPPT.
 
The idea is to have only one elevated at one time, the east facing one elevated in the morning the west facing elevated to catch the setting sun. It was the best I could come up with, with the available roof space. It has to be better than a flat panel.
I hope to get some meaningful data of recovered solar energy through my Victron BMV and MPPT.
it will be interesting to see how it goes.
Will it matter if only one is elevated at a time if it is casting a shadow on the other due to the low height of the sun? Would it be more effective if the tilt was in the centre of the roof rather than the sides? Then there would be no shadow as the tilted panel is behind the flat one and not in front.

If my understanding of your setup in the photo is correct, it does mean you will only have one panel "active" ever, so for the tiliting to give better results, it needs to be better than 200% of what you would harvest from that panel when flat (to make up for the other one that is not doing anything).
 
it will be interesting to see how it goes.
Will it matter if only one is elevated at a time if it is casting a shadow on the other due to the low height of the sun? Would it be more effective if the tilt was in the centre of the roof rather than the sides? Then there would be no shadow as the tilted panel is behind the flat one and not in front.

If my understanding of your setup in the photo is correct, it does mean you will only have one panel "active" ever, so for the tiliting to give better results, it needs to be better than 200% of what you would harvest from that panel when flat (to make up for the other one that is not doing anything).
My theory is like this, the panel furthest from the sun is elevated and thus catches the sun as it rises, the panel nearest the sun catches the sun as it rises higher in the sky. Then before mid day have both panels laying flat. Then at some point raise the other panel to catch the setting sun.
I just need to test my theory.
I did start with the panels tilting away from each other but realised that the raised one cast a shadow over the flat one.

IMG_20191107_093620.jpg
 
When I used solar I found this solar angle calculator helpful and the results surprising.
 
My theory is like this, the panel furthest from the sun is elevated and thus catches the sun as it rises, the panel nearest the sun catches the sun as it rises higher in the sky. Then before mid day have both panels laying flat. Then at some point raise the other panel to catch the setting sun.
I just need to test my theory.
I did start with the panels tilting away from each other but realised that the raised one cast a shadow over the flat one.

I've just realised the photo is from my first attempt which did shade the panel.
How you have it set up now with the central tilt makes perfect sense to me and should logically give a benefit :)

What you may need to do is play around with the way the panels are connected (series or parallel or independent)? I did a brief experiment tilting a single panel in an array and I can't recall the exact effect other then it didn't improve anything.
Will be very interesting to see the results you get.

I've got some plans on my own array but not bothering to do anything for quite a while as where I can test is too much in the shadow this time of year so results would be very inconclusive.
 
How you have it set up now with the central tilt makes perfect sense to me and should logically give a benefit :)

What you may need to do is play around with the way the panels are connected (series or parallel or independent)? I did a brief experiment tilting a single panel in an array and I can't recall the exact effect other then it didn't improve anything.
Will be very interesting to see the results you get.

I've got some plans on my own array but not bothering to do anything for quite a while as where I can test is too much in the shadow this time of year so results would be very inconclusive.
Due to existing solar and my solar parallel works best for me. I can only use the two 150W panels in series but for a parallel config I can include the original 100W panel. The 400W parallel has always beaten the 300W series config.
Tilting is the best idea just a fiddle to construct.
My 50W rotating has exceeded my expectations in the few test I've given it.
 
TBH I think the difference between parallel and series is fairly marginal, so 400W whatever will always beat 300W whatever.
My comment was more to do with how one panel that is (presumably) harvesting significantly more than another panel is best 'joined up' with that panel. In that situation, what difference would parallel vs series vs separate controllers make, if any?
 
If only Victron MPPT's were 2 a penny.

One day it may be worth experimenting, sensing individaul panel voltage and current but I don't believe solar is really the answer to the world's problems. I'll get more data and having purchased the panels I intend to have a play. The hardest bit is mounting them to the van, an all singing all dancing rotating / tilting / connection switching solar array is easy in the garden. But then the sun needs to shine.

For the price of a dozen MPPT's I could have an Efoy generator, then it's just the price of the Methanol.

My rotating panel has GPS so knows it's location and so calculates the sun's azimuth and elevation. It doesn't tilt because that is difficult the make in a portable system but it's always pointing in the right direction should the sun come out from behind a cloud. My main aim with this is to capture the rising and setting sun.
 
Isn't the arc of the suns path linear? If so you'd only need to be able to adjust the angle of the vertical shaft.
 
Isn't the arc of the suns path linear? If so you'd only need to be able to adjust the angle of the vertical shaft.
We'll 360* / 24 hrs = 15 so you'd think 15* for every hour. Wrong, the sun rises quicker at the beging of the day and drops quicker at the end of the day. Around mid day there is more change in azimuth than elevation (if that makes sense?) There are some calculations on the www that explain it.
 
Around mid day there is more change in azimuth than elevation (if that makes sense?)
Assuming your panel would like to receive it's photons at 90 degrees, and the suns arc is non linear. Would not just a small change of making the post angle adjustable be worth it still? So going through it's range of rotation it looks up a little at the suns maximum elevation?
 
I had the pleasure of being at the Moffat meet I have tilting panel and was averaging 15amp for 400 watts of solar .My batteries where down to 70% first thing on the morning but just after lunch where fully charged again.I park my van more to the east so I would get most of my sun in the morning and it worked fine for me .I have 200amps of lithium batteries and I don’t bother tilting them in the summer as there is no need to for me .Its the only way your going to get the best out your panels.
 
Today I saw these output currents for my setup on van and trailer. A single 100 watt horizontal panel gave less than 1 amp charge. The 100 watt horizontal plus 2 X 150 watt horizontal panels gave 5 amps charge. The 100 watt plus a 150 watt horizontal and a 150 watt panel elevated as shown gave 10 amps charge.
 

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