Date: Wed, 10 Oct 2001 22:34:35 +0800 From: Raymond <[EMAIL PROTECTED]> Subject: Re: [LIBRETTO] Raymond's Solar Reply
>>>There exist bike mountable units which could supply as much >>>as 20 Watts at 15 Volts in direct sunlight. >> >>Yes, in DIRECT sunlight. Those claims vary wildly - you'd do well to actually try it >out because I doubt you'll constantly have full summer sun falling onto that thing. >Take their claims with a very large grain of salt - a bit like laptop battery life >claims ;-) > >Solar energy outside the atmosphere as around 1300W/m^2, around 50% of this makes it >to sea level. Efficiencies of solar cells seem to top out at around 25% - so you'd >need an area of around 0.12m^2 at the equator, at noon...probably four times that to >have any chance of making enough energy at other latitudes/times of day - this is in >danger of becoming a wing :) Well the 20 watt 12 volt polycrystalline cell I'm looking at now (its actually a 16.8 volt panel but they assume some load) has a size of 50cm by 42cm ... 0.21m^2 ... those dimensions however wouldn't be too hard to fit onto a bicycle one would imagine ... you'd need bigger if the panel is flexible amorphous though ... bear in mind that you'll need to keep your panel REALLY clean if you want good power out of it - even if only one section is dirty it'll reduce the current that can go through the system and therefore the efficiency of the other sections. Of course, if you wanted a wing there's a 80 watt 12 volt panel available thats 50x145cm = 0.725m^2 if you want ;-) It just occurs to me though, with something that size you could always turn it into a 'roof' for your bike I guess ... hehe - Raymond ************************************************************** http://libretto.basiclink.com - Libretto mailing list http://libretto.basiclink.com/archive - Archives http://www.picante.com/~gtaylor/portable/faq.html - FAQ -------TO UNSUBSCRIBE------- Reply to any of the list messages. The reply mail should be addressed to: [EMAIL PROTECTED] - Then replace any text on the message's subject line: cmd:unsubscribe --------TO UNSUBSCRIBE DIGEST------ Do above but with this on subject line: cmd:unsubscribe digest **************************************************************
