Solar panels for greenhouse lighting/ventilation.

[ranunculus]

Does anyone have experience and/or advice about utilising solar panels for lighting and ventilation in an alpine house please?

[TC]

I did think about lighting using solar panels.  I think either Aldi or Lidls were selling outdoor solar panel lighting kits but I came to the conclusion that there would not be enough light in my garden in Winter to charge the batteries in the lighting fixtures.  As for providing enough power to operate mechanical linkages to open ventilators... no way.

Another plan I had was to use a heavy duty car battery connected to a charger and run an armoured cable from my garden shed to the greenhouse.  Use a couple of 12 volt car headlights and put in a car's electric fan.  Even with all these running, it was within the batteries output as it would be continually charged from the mains supply.

I checked this with a qualified electrician and he said it would work safely.  The main advantage being electrical safety without the need of a 240 volt supply in the greenhouse.

There are garden lights available from large garden centres using a rectifier but the current supplied is not large.

I just turned round to look out the window and the clouds are bright yellow although very little wind..the lull before the storm.  I will have to check all greenhouse doors and windows are secure and move any garden pots into shelter.  It's supposed to hit the coast here about 3pm onwards.  I expect a cascade of apples from my tree when it hits ! 

[ranunculus]

Many thanks, Tom ... the 12v battery solution sounds ideal, but my problem is that I'm about as practical as a liquid spanner, so I will have to consult a local oracle to proceed.  I will require occasional lighting and warm weather fans, but the expense of armoured cables is simply too high.

[Giles]

Cliff,
fredg made some postings a few years back, I think, about solar panels for circulating water for his insectivorous plants,  ..and possibly a fan too. for ventilation.  Might be worth pm'ing him, as I can't find the post easily myself. It was successful and not at all complicated.
Giles

[brianw]

Many of the boats moored up near me on the Thames have solar panels on, to charge batteries for TV fridge etc. The best source of such things might be chandleries or boatyards or caravan supplies.
I have mains power to my greenhouse for fans and heating the enclosed end, but I am seriously looking at using solar panels alongside to lessen my power bill. Thought of having a dry storage/working area roofed with panels, but not cheap for anything substantial. Payback used to be 8-10 years at one time, not sure about now or how a freestanding setup might effect that.

[Neil]

Cliff for what you need lighting and ventilation you will probably only need a cable with a 1.5mm core size, as you are not going to be drawing much current.  A 50metre reel of that can be bought for about £50 + Vat from an electrical wholesaler. 

[angie]

Cliff that’s something I was thinking of looking into so I would be interested to hear more. I am heating my greenhouse and my koi pond. I use a heat source pump on the pond but I don’t find it works well .

Angie 

[ranunculus]

Many thanks for all your feedback, folks.  I will update you all as soon as a decision has been taken.

[Graeme]

I have looked at a lot of options and if you can run an armoured cable then go with that option - rcd sockets are currently on offer at screwfix

On the solar side there is either the option of using batteries 12v or an inverter to change it up to 240v

when we built an extension a couple of years ago we put in another cable hub on the back of the house to run to the area where the buildings are

There is on the horizon the possibility of using the old Nissan Leaf car batteries for storage or Tessler battery pods but they are about £3.5K at the moment - and you would need somewhere to store them - these are more use for house storage - but the technology on this side is very much in its infancy

I am just starting to look at led grow lights - and that is a bigger nightmare to get a straight answer out of anyone

[TC]

For a 12volt system, there is no need for armoured cable....I just happened to have about 4 meters left when my electrician wired up my garden shed with lighting and a 13 amp ring circuit fed from a consumer box.
A length of domestic cooker cable would be more than sufficient.  My only problem would be routing out a channel from my shed through the concrete base and drilling a large hole to accept the tubing and cable .  The tubing would be domestic quality.  A waterproof socket would be mounted in the greenhouse to take the plugs from the fan and lights.  I have calculated the electrical load and it should work...famous last words.  The main advantage to me is electrical safety...a 12 volt current is harmless in a wet situation and the system would not cost the earth.
Again, in my case, the greenhouse is only 1 meter from my shed which is already safely wired up to mains supply.