Solar tilt in the winter months

[RichardtheGardener]

Hello, 

 

We are just in the process of fitting our solar. We have two 260w panels. We are incredibly low energy consumers. We realize that this won't cover us for the winter months without running the engine or gennie, but want to know what angle to tilt the panels to get the most out of them in the winter? 

 

Any ideas? 

 

Cheers, 

R 

 

[bizzard]

11 minutes ago, RichardtheGardener said:

Hello, 

 

We are just in the process of fitting our solar. We have two 260w panels. We are incredibly low energy consumers. We realize that this won't cover us for the winter months without running the engine or gennie, but want to know what angle to tilt the panels to get the most out of them in the winter? 

 

Any ideas? 

 

Cheers, 

R 

 

You could lash the panel to the stem of a big Sunflower plant,  just below and as close to the big flower head as possible, which always swing about to face the sun and it'll do it automatically.

Edited September 13, 2018 by bizzard

[WotEver]

From here: http://www.greenpower-technology.co.uk/solar-pv/advice-about-biomass/

• Spring:  latitude X 0.98 – 2.3 degrees = angle
• Summer:  latitude X 0.92  – 24.3 degrees = angle
• Fall: latitude X 0.98 – 2.3 degrees = angle
• Winter: latitude X 0.89 + 24 degrees = angle

 

Middle of the UK latitude is roughly 52.4 degrees. 

[Alan de Enfield]

12 minutes ago, RichardtheGardener said:

Hello, 

 

We are just in the process of fitting our solar. We have two 260w panels. We are incredibly low energy consumers. We realize that this won't cover us for the winter months without running the engine or gennie, but want to know what angle to tilt the panels to get the most out of them in the winter? 

 

Any ideas? 

 

Cheers, 

R 

 

To get anything out of your panels, not only do you need to 'tilt', but you need a 'lazy-susan' and move it every 15 minutes as the Sun moves from east to West

[WotEver]

So 70 degrees in winter. 

Getting on for vertical. 

[Sea Dog]

Take 2 solar panels and two bilge pumps, one pairing to port and one to starboard. Power the port pump from the starboard panel and vice versa. Open a seacock, just a bit in autumn and a bit more in winter. As the sun illuminates one panel, the associated bilge pump will run, thus lightening the opposite side and the resulting list will tilt the panel accordingly. If the sun moves to the other side, the situation will reverse. I haven't tried it myself, but it was in some hand writtennotes I found, signed by Bizzard.

[Chewbacka]

13 hours ago, WotEver said:

So 70 degrees in winter. 

Getting on for vertical. 

Which means that either side of noon the sun will come from the side giving a glancing angle and losing a lot of power unless as already stated you rotate as well.  So fixed panels are angled a bit flatter to get more power either side of noon.  This explains it better than I can. https://www.solarpaneltilt.com/

 

Don’ Forget that it is windy in winter and a near vertical panel will act like a sail or even tear itself of the roof

 

Edited September 14, 2018 by Chewbacka

[WotEver]

19 minutes ago, Chewbacka said:

Which means that either side of noon the sun will come from the side giving a glancing angle and losing a lot of power unless as already stated you rotate as well.  So fixed panels are angled a bit flatter to get more power either side of noon.  This explains it better than I can. https://www.solarpaneltilt.com/

 

Don’ Forget that it is windy in winter and a near vertical panel will act like a sail or even tear itself of the roof

 

Yup. I never said it was a good idea, just answered OP’s question

[Jen-in-Wellies]

17 hours ago, bizzard said:

You could lash the panel to the stem of a big Sunflower plant,  just below and as close to the big flower head as possible, which always swing about to face the sun and it'll do it automatically.

I used to have a bit of machinery to do just that. It had two 80W solar panels, mounted to a pole that was tilted by different amounts, depending on latitude and season. During the day a motor would drive the pole rotating a it certain number of degrees every fifteen minutes or so to track the sun over an angle of around 180 degrees. To track you need to average 15 degrees an hour. At night it would rotate back. This was ten years ago when solar panels were very expensive compared with now and having a specific piece of equipment to do this and extract that little bit of extra sunlight was worth doing. It was made by a Czech company I think, imported by a company in Wales, now long gone. These days I've not seen anyone doing automated tracking. The cost and complexity is high compared with just adding more cheap panels and angling them at a best guess.

 

It had all the disadvantages mentioned by other posters. The wind load on it was enormous. It was mounted on a length of scaffold pole, bolted to the boat cabin rear bulkhead via some car exhaust clamps. It had to be dismantled before cruising. I tried once turning the boat around at the mooring in a slight breeze and it acted like a giant sail, making the boat almost impossible to handle.

 

Later I took it out and mounted the panels flat to  the roof. I added an extra 80W panel, which by this point cost a fraction of what I had paid for the first two, giving a similar total amount of power, but without having to dismantle the system to cruise.

 

In the winter solar is rubbish anyway. Having the panels flat to the roof helps with collecting scattered light on the usual overcast days. Only on the rare bright clear days is angling the panels of any additional use.

 

A picture from the dim and distant past below of the tracker mounted, showing just how big and unwieldy it was! Late afternoon, judging from its position.

 

Jen

[roland elsdon]

I read an article recently that suggested it wasnt worth faffing about and lying em flat was the best alround solution, unless you had sufficient panels to be able to loose less tracking  through powered tracking than you gained by them not being at the optimal angle. If you are that concerned you would also have to make sure your boat was aligned due north south and angle the panels east west changing them appropriately through the day. It aint going to happen...

i recon cleaning them daily when you mop the boat is probably more advantagous.

Sorry lost less through tracking motor losses than you gained by optimisation alignment

[LadyG]

I was going to buy a portable 100w suitcase type panel to add to the fixed ones , for use in winter. They cost about £200. I would be on board, and would point them in the general direction of the sun in winter, on nice sunny days, not when its raining Just weak them every 30 minutes or so.

[reg]

I stopped tilting my panels a good while ago with the cost of solar panels coming down significantly I found it easier just to add another panel and lay it flat. 

If you have the roof space then I would suggest this may be a better bet cost wise and requires no faffing around or constant monitoring. 

If you don't have the room for an additional panel then tilting can have a beneficial effect, whether that benefit is worth the hassle or not is up to you. 

If you go for an additional panel with the aim of getting a benefit in winter the I would suggest a higher voltage and lower amp panel coupled to a proper mppt controller should give the best output. 

 

[roland elsdon]

We added another 50w and a decent controller to our basic panel pwm system this year. Result was stunning but 3 months sun may have helped.

[jan-kees]

tilting or moving solar panels is way much more hassle then the extra little bit of energy it give,  if you have space..just slap a few more panels on the boat

[Cheshire cat]

I understand the theory but this has been brought home in the last couple of weeks. The available daylight has fallen significantly and my decorative solar LEDs  give up by half past eight. 

[jan-kees]

what kind of controller are you using ?

 

 

[MtB]

The thing is, solar panels deliver feck-all in winter when laid flat as there is no energy in the sunlight arriving, which is why it is so cold.

 

So tilting them up at the optimum angle results in a power output of feck-all times perhaps 1.7.... which equals....

 

.... have a guess!

Edited September 20, 2018 by Mike the Boilerman

[TheBiscuits]

8 hours ago, Mike the Boilerman said:

The thing is, solar panels deliver feck-all in winter when laid flat as there is no energy in the sun, which is why it is so cold.

Point of Order M'Lud. 

 

There's plenty of energy in the sun in winter - it all just goes to Australia.  I'm pretty sure it is because the hot flies South for the winter like what the birds do. 

 

(Ignore all the inbound comments about tilting the planet, that's just crazy talk.)

[MtB]

30 minutes ago, TheBiscuits said:

Point of Order M'Lud. 

 

There's plenty of energy in the sun in winter - it all just goes to Australia.  I'm pretty sure it is because the hot flies South for the winter like what the birds do. 

 

(Ignore all the inbound comments about tilting the planet, that's just crazy talk.)

 

Agreed. So I’ve edited my post accordingly