I hear what you are saying troon. I never thought the idea was ideal but I live in a tent and am surrounded by trees so I don't have many options such as car batteries. you say an efficiency of 2% but I have read online that you can get 10 to 25% efficiency on a cloudy day. i could light up the panel using a good battery operated device so that it is just as bright as it would be on a cloudy day outdoors. if the panel is just as lit up, then surely it is being hit with the same amount of light particles? another road i am now thinking about is wind power. is it possible to get a wind power fan and place it next to a battery operated fan so that the blades physical meet and the battery one spins the other? i am surrounded by trees and don't have much wind.
Quote: Originally posted by maccaovwillenhall on 23/9/2016 i am now thinking about is wind power. is it possible to get a wind power fan and place it next to a battery operated fan so that the blades physical meet and the battery one spins the other? i am surrounded by trees and don't have much wind.
Sounds like a plan but you'll need a few hamsters .... to take over when the battery runs out.
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Quote: I live in a tent and am surrounded by trees so I don't have many options such as car batteries.
You had a 120Ah leisure battery in your first post. I'll continue to humour you for now as it's a physics lesson…
Quote: you say an efficiency of 2% but I have read online that you can get 10 to 25% efficiency on a cloudy day.
That's the solar panel efficiency on its own. You need to factor in the lamp efficiency: even the best LED lanterns are only around 10% efficient at converting electrical energy to light energy.
100W electrical from battery » 10W light energy from 10% efficient lantern » 2W electrical from 20% efficient solar panel.
Quote: i could light up the panel using a good battery operated device so that it is just as bright as it would be on a cloudy day outdoors.
You really can't. Daylight, even on a cloudy day, is a serious amount of light energy. Photographers use flash guns to simulate it — they only work for milliseconds at a time.
Take a look at the Examples table on this page. To match an "overcast day" you need "TV Studio" lighting levels.
Quote: another road i am now thinking about is wind power. is it possible to get a wind power fan and place it next to a battery operated fan so that the blades physical meet and the battery one spins the other? i am surrounded by trees and don't have much wind.
Now I'm more convinced than before you're having a laugh. That's a marginally less inefficient solution than your prior one: an inverter is what you need, running off the batteries you're using for the hypothetical lantern and fan.
sorry not got access to internet over weekend. yes I have a 120ah leisure battery and I already have an inverter but what I don't have is a good way to charge the battery. if I put the solar panel outside it is likely to compromise the security of my tent, unless I surround it with bushes. what sort of power could I expect to generate if the solar panel can see cloudy sky directly above it but not around it?
Nowhere near as much as you could in decent light - but you may not need that much. What are you running from the battery?
If you already have the panel: get a cheap multimeter and measure the current into the battery under the light conditions you're describing - if your controller doesn't tell you already.
To go back to prior points, a 120Ah 12V battery has 1440Wh energy. The best AA batteries have around 4Wh - so even if you found a 100% efficient way of getting those batteries to charge your leisure battery, it'd take 360 of them to fill it up.
At 2% efficiency (your first idea), you'd need 18,000 of them, which would cost you over £5000 per full charge. If you're in Willenhall, I'll happily drive over and supply you with a new, fully charged battery for only £4000 a time.
thanks for replies troon. from what I can gather from responses on here the lantern is not going to work lol I am going to get some ladders and put the panel up in the tree. there may be about 10 meters of distance between the panel and battery. how much power do you think I would lose? also, I will be using a tv and freeview box off battery. I have checked it out and says its about 20-25w, taking into account it a 19inch lcd
Why not replace the battery lantern for a 12v led strip light and power it from the leisure battery. You could then sell the excess energy to the national grid.
How about farting into a paper bag and using it to cook with instead of a gas cartridge? Just where is this ridiculous conversation going? If you want more charge, get a bigger solar panel, oh, and use the sun (even when it's hiding behind a cloud) end of.
------------- The Sun always shines on TV.(and not on my caravan!)
Quote: Originally posted by Rob Johns on 09/10/2016
How about farting into a paper bag and using it to cook with instead of a gas cartridge? Just where is this ridiculous conversation going? If you want more charge, get a bigger solar panel, oh, and use the sun (even when it's hiding behind a cloud) end of.
Nooooo! Don't shut it down - I'm really enjoying this thread.