Solar powered garden lights

[annette]

I bought some solar powered garden lights for around the place and I'm trying to learn as much as I can about solar power too. I want an off grid system eventually.

I have read, and even on the box, that it needs a certain amount of sunlight to produce the energy for the light.

Now I got them out just before and put them together and when I put my hand over the top of the solar part, it lights up. Take the hand away and it doesn't light up.

So my question is, does solar respond to heat and not just light like all the info I have read? Or is it the heat from the light that generates the energy? Can you run solar with heat (like from a compost heap) and not light?

Sorry if this sounds like a stupid question.

[jeremy]

solar panels use photons to generate electricity so heat shouldn't generate any power. most solar systems become less efficient if they heat up too much.
i think your solar lights are designed to generate electricity when there is light and store it in a battery, and when it senses that it is dark (like when you put your hand over it) then it will use the stored electricity to power the light.

[jeremy]

could have a look at this. it explains how solar garden lights work. http://home.howstuffworks.com/solar-light2.htm
if you want the science behind solar photovoltaic have a look on wikipedia.

[pebble]

Jeremy, at first I read the Schumacher quote in your first post as something you had written as part of the post on solar garden lights. It made perfect sense :-D

[eco4560]

While they are cheap and a bit nasty - I do like my solar lights. Jeremy is right - they only turn on when the sun goes down (or you shade the panel!). I put mine next to my pond to attract insects to keep the frogs well fed.

[annette]

Thanks for the info Jeremy. I suppose what threw me was that these lights were new and I had only just put them together. They had no exposure to sunlight at all as they had been in the box for about a month before I got to put them together. And it was late in the afternoon. So I didn't think there would be any light being generated by the solar cell until they had a chance to be in the sunlight. The whole 6 of them shined all night and didn't go off till 6.30am this morning. I figure there must be some sort of battery energy stored in it. The instructions just said they need to have a least 8 hours of light before they would work.

[Grahame]

Most of those little solar lights actually have a AA rechargeable battery in them - there was probably some charge in it already.

[Pakanohida]

Mine do not even work in winter due to the low sun level relative to the high tree canopy to my south which I have no control over, however as Eco said, they are great at dusk.

Eco, thanks for the tip! I should put one near my aquaponics pond experiment!!!

[pebble]

Most of those little solar lights actually have a AA rechargeable battery in them - there was probably some charge in it already.

Wouldn't they turn themselves on in the darkness of the box?

[Grahame]