Admin vs Streetsleeper Solar Shootout


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A really good comparison and thanks for posting Phil.The facts that I find interesting are the winter readings because that is the time of year when you need the most power because of extra heating/lighting etc....
Both the solar systems are much larger than the average installation,most folks just have an 80 watt solar panel and an extra leisure battery.Because of the size of both of these systems they should have a surplus of solar power in the summer when the sun is highest in the sky paradoxically when you don't need it.
The tilting solar panel is a clear winner in my opinion,there did use to be a gps controlled solar panel that tracked the sun(sammy solar I think?),not sure if it's still available now.
could you possibly repeat the tests on a cloudy day? ( Cheeky request )
I did that right at the start and the conclusion I came to, if it's overcast the solar panel harvests more laying flat on it's back; can't tell you the actual figures but it was enough to convince me that's the way it would be.

You only need to look at solar farms to see that angled panels is the way to go.
Hello Eric,
That's basically the bottom line. When I decided to do the conversion all I did was have a good look around: in fact, when we did the test at Hereford the solar panels on the clubhouse were virtually at the same angle and the same direction.


One of the 'gotchas' with tilted panels is unless you have a multi-directional tilt system, you do have to park in a certain general direction (i.e. South) to get the benefit.
This is often not possible of course - on campsites, the pitches are laid out such that you point wherever the pitch does. At the festivals I go to, you end up parking to fit into the allocated space and you could face any old way.
This can be a real problem with the smaller campervans with the poptop roofs, such as the VW Campers. Those roofs are usually hinged one side - so it is pot lot if you end up tilting the roof (and therefore the panels) towards the sun :p or away from it :cry:.

There is definately a benefit of presenting the panels right to the sun (and sometime over the winter I'll likely be adapting my setup with the bits I got to do so ages ago :rolleyes: ) but I would think don't expect to be able to tilt when camped more than 25% of the time on average?


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Really you need both as when travelling flat panels will harvest anything available, when parked then tilted. Most vans/people would not be able to take tilting panels on the roof so suitcase or lose panel would be better. Still not going to be a year round solution for folks like me if parked any length of time though. Must do some tests to see exactly what uses power but don’t seem to stop long enough to do it. I reckon I am somewhere between 75 and 100 amps at the moment if we have heating on and everything else.

don't expect to be able to tilt when camped more than 25% of the time on average?
Hello David,
Fortunately I don't do music festivals, unless you count the Henley-in-Arden one, so the odds are looking better already. I think I can safely say all the meets we attend are held, normally, in wide open spaces and I am quite prepared to park a little bit away from the other vans to achieve a southerly direction on the solar panels. I don't think it will be needed so much in the summer months so the percentages are looking more favourable.


Just go to prove size is not everything.🤣🤣🤣


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Very interesting Phil, thank you. And a nod to Rae as well. ;)

Brill post but as its gray sky here 80% of the time i just went with flat panels on the roof,i do have a 50w free standing panel which could fit behind my windshield and point southish.

Very interesting Phil, thank you. And a nod to Rae as well. ;)
Hello Debs,
Speaking for myself, had the wind turbine not been a failure, I would have never thought of going down this route. As it happens, I now look back and think this was the right decision; I may still have another go at the wind turbine but more as a project than a means to an end.


Very interesting thread. With great results for you both. Looking forward to the next instalment.
Rae, looking forward to the thread on the hydraulic system you will put in place to lift the panel.
Cheers. David
Phil, Managed to follow Raes thread. But could not see yours on your solar panel fit. Where should I have been looking?


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A really helpful thread, thanks.

On a cloudy day the freestanding (or adjustable) panels are best laid flat, in other words there is no advantage to raise them.

There is also no need to constantly adjust the panels during the day, every 4 hours is usually enough for close to maximum gain. It is also incorrect to point the panel directly at the Sun, this can result in a slightly lower harvest of power. This is because on a hot Summer day the panel itself absorbs heat and functions less well. The difference is not big and will not last long as the Sun is moving slowly.

The above comments are not guesswork, they are my observed results over a number of years using a freestanding panel and a digital Ammeter to check results.
For me the cloudy days are the important ones. I need to harvest about 30AH a day to keep up with the overnight demand of my medical equipment. On sunny summer days my portable panels achieve this comfortably by the middle of the day but the cloudy ones are more challenging. Confirmation that laying them flat on the roof is probably best on cloudy days is very helpful because I prefer to secure them up there out of the way.

I have already gone over to LiFePO4 which helps. Better charge efficiency, lower Peukerts factor, higher charging rates (BtoB when on the move) but it is a more expensive option and probably not for everyone.

You only need to look at solar farms to see that angled panels is the way to go.
I don't doubt that the solar farmers have positioned their fixed panels to achieve the optimum results over the whole year. However for me optimising the bad days is more important.


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Angles ....
As has been posted the main challenge is winter.
Summer is easy more than enough power.
I believe that in winter there are 2 different best angles.
1 if the sun is shining then the panel is best perpendicular to the sun but no need for continually moving .
Look at the peak of the sine wave curve all quite high between 70 and 90.
So if the sun angle is 40 degree panel should be bate 50 degree.
2 a bright but cloudy day then a more horizontal angle might well bee better as the whole sky is providing the solar energy.

Solar farming is different..The power in summer is up to 10 X that in winter and they will get more energy by tilting for summer use


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