The title asks the question. Why is 'at an angle' different to laying flat under the Sun? Surely the Sun is such a big light source that it makes no difference?
Peter_n_Margaret said
12:41 PM Aug 17, 2019
I did you a little sketch. Most of the light energy is coming directly from the sun. Some is reflected, but that is minor by comparison. The angled panel will be exposed to almost double the light compared with the flat panel.
Cheers,
Peter
-- Edited by Peter_n_Margaret on Saturday 17th of August 2019 12:42:06 PM
that is a fairly accurate analogy Peter, you can get twice as much harvest throughout the day if you can keep the panels correctly angled to the sun. That is only the case when you have clear skies and the sun is not blocked at all, there is virtually no improvement and maybe even a bit of a loss when the sky is cloudy. That is because the sun's active rays are reflected from the ground/water/snow back onto the clouds and then reflected at different angle back to the ground. Solar panels work the best when the light is harsh enough to have you squinting or looking for the polaroid sunglasses, it is not light itself but the sun's rays that burn the skin and dazzle the eyes that actually produces the output from a solar panel. Shine torch, led or fluro lights on a solar panel at night and you can see them clearly yet nothing will be produced, just the wrong sort of light waves. They will produce directly under mercury vapour lights though, not too sure about the sodium vapour ones though (the orange light ones)
T1 Terry
Whenarewethere said
02:43 PM Aug 17, 2019
The old Halls Creek site has a solar panel array of about 12 panels which are long dead (haven't got photos with me). On each side there is a cylinder which heats up to change the balance of the array so it faces the sun. In those days panels cost 3 arms & 2 legs & a couple of ..... so you wanted to get every last bit of energy out of them.
Peter_n_Margaret said
02:54 PM Aug 17, 2019
Whenarewethere wrote:
The old Halls Creek site has a solar panel array of about 12 panels which are long dead (haven't got photos with me). On each side there is a cylinder which heats up to change the balance of the array so it faces the sun. In those days panels cost 3 arms & 2 legs & a couple of ..... so you wanted to get every last bit of energy out of them.
Yes, thee days with fixed panels it is easier and cheaper to simply have more panels and "set and forget".
Those with portable panels can move them around and angle them to collect more energy if they have the inclination.
There are a variety of mechanisms for tracking the sun, none that I have seen are suitable for RV use.
This one on a Pilbara cattle station needed regular "fixing". It was eventually replaced with a larger array of fixed panels.
I have a single 90w fixed (flat) panel and when travelling it and the alternator cope well enough partly because we have modern gadgets and use power frugally. Within reason the flat fixed panel will collect no matter my camper orientation. I also have a 160w folding portable panel set that I can use to chase the sun when camped longer in one spot. The only time I've had issues was after 10 rainy and cloudy days in Tassie and everyone in camp was struggling.There are lots of opinions, rules of thumb and formula around to calculate solar needs but I work on the principle of need enough solar harvesting to replace my consumption. If start to repeatedly fall short, it's more fixed flat solar not angled. Angled solar means facing everything the right way.
T1 Terry said
04:48 PM Aug 17, 2019
The large solar farms being erected alone the Murray Bridge-Mannum road all solar track on one axis to follow the sun from sunrise to sunset. Acres of panels at each solar farm, even with solar panels as cheap as they are now, these people are setting up solar tracking, it must be worth their while to solar track rather than have fixed panels or they wouldn't be doing it.
The bother in law has a remote house on the side of the Huon Valley in Tassie. He has both hydro and solar tracking using a system any cow ****y would be proud of :lol: The solar tracks East/West via a lever and pole attached to an old wheel and tyre, this is in a drum with a water feed and a drain valve controlled via clothesline wire and pulleys from the side of his house. There is a plate with a circle cut out of the centre and a second flat plate mounted a set distance below it and all mounted to the solar panel frame, a piece of water pipe pivoted at each end on long poles to get the height above the house. It is set up so the sun shines a perfect circle on the bottom plate when the sun is at the correct angle to the plate. By controlling the water flow into the drum, the tyre starts to float tilting the panels at a speed that tracks the sun. At the end of the day he pulls the plug on the drum and the water flows across his vegie garden, in the morning the plug is reset via the clothesline cable control, and the system starts all over again. If he isn't going to be home for the day, he just sets the panels to flat for mid day and turns the water off. Summer/winter adjustment is by sliding one pole up or down on the ground mounted pole with the mths marked off to get the correct angle for the high end of the solar tracking array.
The hydro is even more agricultural, but he only runs that at night if he needs it, the Pelton wheel on the 12v alternator makes a lot of noise in such a quiet area so he only uses it when needed.
T1 Terry
Gavinwr27 said
10:06 PM Aug 17, 2019
Thanks guys, I get it now
Mamil said
04:02 PM Aug 18, 2019
Ten years ago when I got into the solar game, tracking systems were popular as the cost of panels made it worthwhile. Nowadays, all other things being equal it's cheaper to throw in about 20% more panels to compensate for them not being at the optimum angle all day. We did build a solar farm with single axis tracking recently, but that was only because the owners wanted the smallest footprint on the ground for the given output. It cost them more to build and will cost more to maintain, but that's their choice.
Tony Bev said
10:51 AM Aug 19, 2019
Before I purchased my solar panel, I did some experimenting (err playing around) with a portable 180 watt solar panel, I borrowed from my grandson
Do not quote me on the figures as I am only going from memory
Angled to the sun gave about 140 watts
Laying flat gave about 90 watts
I therefore agree with Peter (Peter n Margaret), explanation
My rule of thumb now (for the future), is to calculate how many watts I require, then purchase double of what the manufacture states, on their stickers, and lay the panel/s flat
T1 Terry said
11:46 AM Aug 19, 2019
Tony Bev wrote:
Before I purchased my solar panel, I did some experimenting (err playing around) with a portable 180 watt solar panel, I borrowed from my grandson
Do not quote me on the figures as I am only going from memory
Angled to the sun gave about 140 watts
Laying flat gave about 90 watts
I therefore agree with Peter (Peter n Margaret), explanation
My rule of thumb now (for the future), is to calculate how many watts I require, then purchase double of what the manufacture states, on their stickers, and lay the panel/s flat
Not so much the instantaneous output, more the total harvest throughout the day. Starts earlier and ends later with closer to full output all through the day, not just the hr either side of mid day.
A good friend made up two solar tracking units out of old big dish satellite dishes, you know, those huge black wire mesh things that appeared in a lot of backyards moons ago. He modified the set up to use the solar trackers available on Evilbay and the two set ups are mounted next to his house/granny flat. The whole place now runs on solar/battery/inverter power, but he does have a diesel heater rigged up to warm the flat in winter.
He scored a set up for me a mth or so back, project number ..... I've lost count actually, but it will go up by the river to power my pump that waters the lawn/garden and keeps the toilet water tank full. We can filter that water and add it to our tank water if needed and it's looking like we might be in for a very long hot summer for the next few yrs.
T1 Terry
Bagmaker said
08:22 AM Aug 20, 2019
The increased angle also helps cooling
Aus-Kiwi said
07:56 PM Aug 31, 2019
It helps in my case on house . One system is 50/50 facing north / west . The other is 100 % facing north . Theres atleast 15 % difference Especially this time ( winter) of the year . The panels facing west does help in summer giving a slightly longer charging time.. assume it would be no different on vehicle ?
The title asks the question. Why is 'at an angle' different to laying flat under the Sun? Surely the Sun is such a big light source that it makes no difference?
I did you a little sketch.
Most of the light energy is coming directly from the sun. Some is reflected, but that is minor by comparison. The angled panel will be exposed to almost double the light compared with the flat panel.
Cheers,
Peter
-- Edited by Peter_n_Margaret on Saturday 17th of August 2019 12:42:06 PM
T1 Terry
The old Halls Creek site has a solar panel array of about 12 panels which are long dead (haven't got photos with me). On each side there is a cylinder which heats up to change the balance of the array so it faces the sun. In those days panels cost 3 arms & 2 legs & a couple of ..... so you wanted to get every last bit of energy out of them.
Yes, thee days with fixed panels it is easier and cheaper to simply have more panels and "set and forget".
Those with portable panels can move them around and angle them to collect more energy if they have the inclination.
There are a variety of mechanisms for tracking the sun, none that I have seen are suitable for RV use.
This one on a Pilbara cattle station needed regular "fixing". It was eventually replaced with a larger array of fixed panels.
The bother in law has a remote house on the side of the Huon Valley in Tassie. He has both hydro and solar tracking using a system any cow ****y would be proud of :lol: The solar tracks East/West via a lever and pole attached to an old wheel and tyre, this is in a drum with a water feed and a drain valve controlled via clothesline wire and pulleys from the side of his house. There is a plate with a circle cut out of the centre and a second flat plate mounted a set distance below it and all mounted to the solar panel frame, a piece of water pipe pivoted at each end on long poles to get the height above the house. It is set up so the sun shines a perfect circle on the bottom plate when the sun is at the correct angle to the plate. By controlling the water flow into the drum, the tyre starts to float tilting the panels at a speed that tracks the sun. At the end of the day he pulls the plug on the drum and the water flows across his vegie garden, in the morning the plug is reset via the clothesline cable control, and the system starts all over again. If he isn't going to be home for the day, he just sets the panels to flat for mid day and turns the water off. Summer/winter adjustment is by sliding one pole up or down on the ground mounted pole with the mths marked off to get the correct angle for the high end of the solar tracking array.
The hydro is even more agricultural, but he only runs that at night if he needs it, the Pelton wheel on the 12v alternator makes a lot of noise in such a quiet area so he only uses it when needed.
T1 Terry
Do not quote me on the figures as I am only going from memory
Angled to the sun gave about 140 watts
Laying flat gave about 90 watts
I therefore agree with Peter (Peter n Margaret), explanation
My rule of thumb now (for the future), is to calculate how many watts I require, then purchase double of what the manufacture states, on their stickers, and lay the panel/s flat
Not so much the instantaneous output, more the total harvest throughout the day. Starts earlier and ends later with closer to full output all through the day, not just the hr either side of mid day.
A good friend made up two solar tracking units out of old big dish satellite dishes, you know, those huge black wire mesh things that appeared in a lot of backyards moons ago. He modified the set up to use the solar trackers available on Evilbay and the two set ups are mounted next to his house/granny flat. The whole place now runs on solar/battery/inverter power, but he does have a diesel heater rigged up to warm the flat in winter.
He scored a set up for me a mth or so back, project number ..... I've lost count actually, but it will go up by the river to power my pump that waters the lawn/garden and keeps the toilet water tank full. We can filter that water and add it to our tank water if needed and it's looking like we might be in for a very long hot summer for the next few yrs.
T1 Terry