[MLB-WIRELESS] Solar Power - How much battery?

[Steven Haigh]

On Thu, Dec 06, 2007 at 02:53:30PM +1030, Kim Hawtin wrote:
> gregsonm at aanet.com.au wrote:
> > Question... how do you calculate the amount of battery a solar panel can
> > charge?
> > 
> > I know some of you will say it depends on how much sun there is... which
> > would be right. But I am looking for a basic calculation to make sure I
> > have the maximum battery capacity possible.
> > 
> > For example, if I use an 80 watt solar panel, what would be the amount of
> > battery amp hours I could charge?
> > 
> > All advice greatly appreciated... Mark
> 
> see if you can dig out the video that the guys in north island new zealand
> at linux.conf.au in dunedin in 2006, on their Wireless Network.
> 
> anyhow, i asked them a lot of questions afterwards about this topic and
> they designed their system to go three days without significant daylight.
> so, that solar panel and battery array need to be three times the size
> of what you need to deliver in a given day.
> so power consumption in a day, needs to be delivered in 5-9 hours of daylight.
> and then you need to be able to fully charge you batteries in say, 7 hours.
> that 7 hours charge needs to be enough to run the AP for 3 x 24 hours.
> that make sense? i don't know the area you are putting this in, but the
> NZ guys AP was literally on the top of a mountain, that was a days hike up
> and a days hike down. hopefully your AP is not quite that remote ;)

More food for thought using back-of-napkin type calculations...

You'd need 2 x 80W panels + ~550Ah of batteries to run a load (2 x APs etc) drawing 2A @ 12v on a 24/7 basis based on fixed solar panels etc.

-- 
Steven Haigh

Email: netwiz at crc.id.au
Web: http://www.crc.id.au
Phone: (03) 9001 6090 - 0412 935 897

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