Oyster satalite to solar conversion (1 Viewer)

[Vic. Parsons.]

A few months ago I set about turning our Oyster satalite dish into a sun tracking solar panel.
I first made a bracket to replace the original dish bracket and mounted the 80 watt panel.



I had to wait until we were in Portugal to meet up with electronics wizz Grant Needham who had made and programmed a new controller to fit the original Oyster wiring harness. This is a prototype with power switch, 2 button menu and small LCD screen.
The next picture is Grant wiring up the controller. (The case is made from an old cigar box).



On the panel bracket we fitted a light sensing diode in a deep tube but later added a piece of 45 degree cut tube to act as a deflector to prevent stray light reflected off the roof from giving false readings. (This can be seen at bottom right in the videos).

There were a number of small programming glitches when we first tested it, but over the course of a few days we managed to iron out the problems and it's now working perfectly.

The functions are:
Auto:
Find the sun, which deploys the panel and uses the diode and dithering to accurately locate the sun.
Next, it does a 5 degree clockwise turn every 20 minutes also with a dithering function to account for the sun's arc. The LCD displays a countdown to the next operation.



Park:
This will bring the panel down to the parked position.
This function also works when the ignition is turned to start the engine.
We're also going to add a park when dark feature.



Manual:
This allows individual button presses for up, down, clockwise and anti-clockwise with a 5 degree shift for each press.

There is also a setup menu and a voltage readout for the light sensing resistor.

We're now working on a second prototype which will work on a bluetooth connection to a smart phone with an app to control all the above functions so that the control unit can be hidden away in a cupboard instead of being surface mounted.

We're also thinking of making a kit for DIY installations which will include the panel bracket, controller and app along with full installation instructions.
This won't happen until we return to the UK next year but if you're interested in a conversion then PM me and I'll add you to the list of Interested parties.

Thanks for taking the time to have a look and hope it gives you some ideas as to what to do with an old satalite dish when other forms of tv reception eventually make it redundant. It's also a good alternative to removing an Oyster dish which has been known to be a difficult process. ?

 

[MisterB]

sounds like a brilliant idea to make a good use of redundant technology - but you dont give an indication of price or test results to see if its worth the outlay - however having said all that, i still think its a great idea

 

[Vic. Parsons.]

sounds like a brilliant idea to make a good use of redundant technology - but you dont give an indication of price or test results to see if its worth the outlay - however having said all that, i still think its a great idea

It's still early days and at present, it's still only a prototype. The final unit would need to be priced up once the system is finalised and once we return to the UK next year.
As for test results, it's only been operational for 3 days so a bit difficult to give test results at present, but, it's looking good so far. ?

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[Winger]

Get a patent on it! Great idea

 

[Allanm]

I wonder how long the solar panel has to be deployed before the extra solar power being gathered compensates for the power taken to operate the motor to get the panel into position , move it around and then retract It.
otherwise, it seems a great idea

 

[Vic. Parsons.]

I wonder how long the solar panel has to be deployed before the extra solar power being gathered compensates for the power taken to operate the motor to get the panel into position , move it around and then retract It.
otherwise, it seems a great idea

Oyster already make a sun tracking solar panel (at a cost of only around £2500 ?). I would guess they use similar electric motors (electric window motors) as in their satalite systems to drive the panel and would have worked out the energy loss versus gain equation before going into production.
Given the short duration the motors are running each day for deployment, tracking and park, I would imagine the overall amp usage would be minimal compared to the gain through charging.
I will get Grant to take a look at that aspect anyway, as it may be worth working out to get a clear picture of efficiency.

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[Richard n Ann]

The gains will be massive in winter ??

 

[Vic. Parsons.]

Having thought a bit more on the energy consumption of the system it occurred to me that Oyster satalite dishes often make a number of 360 degree rotations and vertical movements before locking onto the satalite, granted, it doesn't move again until its parked, but I reckon this would more often than not, consume more battery power than a whole day of tracking the sun and it's power that is not recovered in the process.
On that basis, I reckon this setup is probably much more energy efficient than using a satalite dish for it's intended purpose. ?

 

[jongood]

I think its an excellent idea as long as its cheaper than Samy Solar. Would it not be possible to mount the PV panel so you can keep the satelite dish and switch between the two uses?

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[Vic. Parsons.]

I think its an excellent idea as long as its cheaper than Samy Solar. Would it not be possible to mount the PV panel so you can keep the satelite dish and switch between the two uses?

The problem with keeping the dish is having two controllers working through the same wiring harness, I guess it could be done though.
But the main problem would be the LNB arm which needs a fair bit of elevation to clear the housing before rotating, with the solar panel at say 50 degrees, this would not work unless the LNB arm was locked against the dish, which would be difficult to overcome.
Also, the coax running down the spindle on the Oyster base would leave no room for the two extra wires (solar positive and light sensing resistor).
As it is, we've used the metal Oyster head as the negative pole to avoid one extra wire going through the spindle.

 

[MisterB]

just an idea. but would it be possible to adapt it for other motorised domes/dishes, in particular old domes as they are becoming obsolete due to changes in sat technology? it might open up the market a little bit more for your project?

 

[Vic. Parsons.]

just an idea. but would it be possible to adapt it for other motorised domes/dishes, in particular old domes as they are becoming obsolete due to changes in sat technology? it might open up the market a little bit more for your project?

I'm pretty sure it could be adapted to any satalite system so long as there are two motors and micro switches.
It might be a bit of a problem with the dome type as they have an enclosed dish, but if the dome was removed and the mechanicals and electrics can be made weatherproof, then I guess it would be possible.

I think its an excellent idea as long as its cheaper than Samy Solar. Would it not be possible to mount the PV panel so you can keep the satelite dish and switch between the two uses?

Having looked at the price of Oyster's samY solar, (£2700) I reckon we would be way under that price. I notice though, for that system to incorporate the dish and panel, the whole thing rotates as a single unit, so the problem with the LNB arm is overcome.
This can't be done when converting standard Oyster dishes.

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[Vic. Parsons.]

Ok, just had a chat with Grant and we reckon the kit would come in at around the £500 mark.

 

[Richard n Ann]

How strong is the base? Would it be damaged if the wind gets under it?

Our 150w panel tilts south but is fastened in 4 positions so it's sturdy.

 

[Vic. Parsons.]

How strong is the base? Would it be damaged if the wind gets under it?

Our 150w panel tilts south but is fastened in 4 positions so it's sturdy.

I doubt it would be any more vulnerable than the dish would have been.
It's been mounted on the roof for 4 months in all conditions with no problems.
I think with it deployed in very strong winds you'd need to use the same judgment call as with a satalite dish.

If it gets really windy, bear in mind, that even parked, it will still produce power.

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[DBK]

This website has some interesting test results. Its conclusion is by tilting a panel to point at the sun the gain is at most 20% over a flat panel. But this is for a fixed installation of course and not tracking the sun but it does suggest the gain might be less than might be hoped. The only way to get a meaningful result would be to compare two identical panels, one fixed horizontally and the other tracking the sun.

My gut feeling is two panels flat on the roof will generate more power than one panel tracking the sun over a year. In winter they would probably generate about the same based on geometry - the sun at an angle of 30 degrees can see only half a flat panel but all of a tracking one. In summer the two flat panels would generate close to twice the power for the critical time, say four hours, around mid-day when the sun is more or less overhead. On cloudy days a flat panel is of course best as light comes from all over the sky so a flat panel gets more radiation than a tilting panel pointing where the sun would be if it could be seen behind the clouds.

Solar Array Tilt Angle and Energy Output

The effect of an array's tilt angle on solar PV energy output may be up to 20% compared to that of flat installations. A comparison of data in two US cities has been completed to exhibit the importance of a solar PV array's tilt angle. As a general rule of thumb, energy output can be optimized...

www.civicsolar.com

 

[Allanm]

Oyster already make a sun tracking solar panel (at a cost of only around £2500 ?). I would guess they use similar electric motors (electric window motors) as in their satalite systems to drive the panel and would have worked out the energy loss versus gain equation before going into production.
Given the short duration the motors are running each day for deployment, tracking and park, I would imagine the overall amp usage would be minimal compared to the gain through charging.
I will get Grant to take a look at that aspect anyway, as it may be worth working out to get a clear picture of efficiency.

I understand that, I just wondered how much extra power you will get with a tracking panel as opposed to a panel flat on the roof.

 

[Vic. Parsons.]

I understand that, I just wondered how much extra power you will get with a tracking panel as opposed to a panel flat on the roof.

I think compared to a fixed tilt panel it would gain between 15% to 30% extra.

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[Richard n Ann]

Mine goes from flat about 2.5amps to raised about 7amps.
Just my very unscientific test looking at the BM2 battery monitor, in September, in Benidorm.
I suspect the gains are a lot more in winter than summer.

 

[DBK]

Mine goes from flat about 2.5amps to raised about 7amps.
Just my very unscientific test looking at the BM2 battery monitor, in September, in Benidorm.
I suspect the gains are a lot more in winter than summer.

What time of day was that? In southern Spain the sun is around 55 degrees at midday in September so I wouldn't have expected a 250% increase in power.

 

[Richard n Ann]

Probably early afternoon because there was a flipping olive tree shading it until about 11am.

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[Richard n Ann]

Could have been October as we were there for about 8 weeks ?

 

[davejen]

£500 for the kit??? you could buy many extra panels for that and probably get more power even when flat and save the hassle....
just sayin.
Cheers, Dave

 

[Richard n Ann]

Get a patent on it! Great idea

Think you can only patent inventions and I'm sure this has been done before. Unless it's got something unique about it ?

As much as I like gadgets, It won't take off because of the cost anyway ?

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[HandyAndy]

How strong is the base? Would it be damaged if the wind gets under it?

Our 150w panel tilts south but is fastened in 4 positions so it's sturdy.

Not if your van faces the other way

 

[Richard n Ann]

Not if your van faces the other way

That's right, ? but we rarely camp in the UK where the site Gistapo insist on where and how you pitch up.

 

[Snowbird]

Have a look at this thread. One we made earlier. https://www.motorhomefun.co.uk/forum/threads/homebrew-solar-tracker.40301/

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[Vic. Parsons.]

Have a look at this thread. One we made earlier. https://www.motorhomefun.co.uk/forum/threads/homebrew-solar-tracker.40301/

Interesting thread, thanks for the link.

 

[Vic. Parsons.]

Have a look at this thread. One we made earlier. https://www.motorhomefun.co.uk/forum/threads/homebrew-solar-tracker.40301/

A little input from Grant after he read the article linked above and to answer some of the questions above:

"I have read this article with interest, and add the following comments after producing my own Oyster Solar Tracker:-

My system is arduino based, using a Promini with a 16x2 LCD and a dedicated relay / sensor board.

The red and white wires (querried earlier) from the motor are pulse outputs to detect motor turns. They are either Hall Effect or Magneto-Resistive, but I do not use them.

With regard to additional solar gain I make the following comments:-

If we consider the sun at 30 degrees to the horizontal a one metre long panel will look like it is only half a metre long (sine 30 = 0.5). If we tip the panel up to be square on to the sun it will then look like it is 1 metre long again, therefore doubling its apparent wattage. The fact that we are tracking the sun only maintains this, and does not add to it at all. therefore a tracked 50W panel will be about the same as a flat 100W panel at an average sun elevation of 30 degrees.

At higher sun elevations (say 60 degrees where the sine of 60 = 0.866) we will only acheive 15% gain (1 / 0.866). Therefore solar tracking is most advantageous in the winter - but I think we all know this!

Queries regarding the loss of energy whilst tracking - versus - not tracking, are simple to justify:-

if we consider the Amp-Hours of tracking then we have a total time of:-

10 seconds to deploy the panel at the start
36 seconds of tracking. Every 20 minutes (for 6 hours) we have 2 seconds per dither
10 seconds to park at the end of the day

This is a total of 56 seconds at 1.5 Amps = 56 / 3600 x 1.5 = 0.046 AmpHours.

Regarding the Solar Gain, we might have a 50W panel working at 50% for 6 hours. Flat it produces 1 Amp, angled it produces 2A, so we gain 1A for 6 hours = 6Ah.

It is not hard to see - it is hardly worth deducting the motor power!

The arduino is ticking over at perhaps 20 mA, so this not really significant either!

Therefore it is definitely worth tracking. My system uses an 80W panel so my gains are even better than the above calculations!

As a side point here, it is well worth mentioning that motorhomers (especially fulltimers) should do a proper energy budget to understand where they are! Our control panel uses 0.6A which on its own sounds insignificant, but over 24 hours this amounts to 14.4Ah. (I generally find that the little things actually amount to more than the big things). Our TV draws 2 Amps, which for 4 hours every evening (= 8Ah) is nearly half of our control panel's draw, for this reason we always shut down completely at night time, and when we are out. If we consider the water pump which draws 8A, and sounds drastic, it is uesd for 10 minutes a day, which is only 1.3 Ah per day, even better!"

 

[DBK]

I guess the best answer is a tracking panel plus more flat on the roof but you would have to park correctly to avoid shading issues. However, I'm not convinced even the increase in winter is significant compared to likely energy consumption by the average motorhome. If a tracking panel can generate 10Ah that doesn't go far if you want to run the heating overnight and watch a bit of TV. We have 200W flat on the roof but probably need 300. I fitted a B2B for energy requirements in the cold months.

I'm not knocking the project but I can't see these being generally adopted.

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