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I need a charger and battery for a cell phone booster. - Page 8

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Posted by ghio on November 13, 2009, 5:58 pm
 

Oh, there is no question about it, wayne has the biggest dick. That's
why he's always at the front of the daisy chain gang shouting "Form a
circle, form a circle".

Posted by ghio on November 13, 2009, 5:52 pm
 
On Nov 14, 12:31am, wmbjkREM...@citlink.net wrote:

Yes wayne. In plain English at the bottom of each page.

Posted by Josepi on November 12, 2009, 11:18 pm
 I guess the majority uses their killfilters on you 'cause you're also
racist.



Posted by Ron Rosenfeld on October 24, 2009, 1:00 pm
 On Thu, 22 Oct 2009 23:10:59 -0700 (PDT), philkryder


Some more information now that I have a bit more time.

Here's another page with what seems to be good data for your location.

http://www.gaisma.com/en/location/santa-barbara-california.html

That shows a nadir of 2.55 for December insolation.

You mentioned that you are up on a mountain or hill.  There won't be any
better information for that location, although PVWATTS2 may enable a bit
better resolution.  One way to obtain better information for a particular
location, that also takes into account various shading factors, would be
measure it yourself.  Given that insolation can vary from year to year (the
NASA values use a minimum of a 10 year average, depending on which database
you utilize), that approach may not be best.

The amplifier requires 6V, 0.5-1.5A or 3-9 watts, depending on uplink
power.  

Your worst month has 2.55 kwH/m^2/day insolation (or 2.55 Effective Sun
Hours).

So that means, as a minimum, assuming, let us say, 6W average requirements
that your panels need to have an output of 6 x 24 / 2.55 --> 56.47 W

That is without considering any system losses, battery charging
inefficiencies, and so forth.

Using a program called HOMER developed at NREL, and considering that you
want your panels flat, it would appear you would require a 90W panel for
full-time use; if you tilted your panels, and also increased battery
storage, you might be able to reduce this to about 55W panels.  Which would
be "better" would depend on the economics.

--ron

Posted by philkryder on October 25, 2009, 8:18 am
 
thanks much.
As you can see, your thoughtful questions have helped me to improve on
my initial guesses in my first post.

It sounds like the key is to make conservative estimates and allow
extra battery capacity to cover anomalies.
Even gathering "perfect" data from averages won't help when we get
several days of unusually cloudy or rainy weather with near zero
insolation.

We are "closed" after dark, so we should see at least 12 hours of
minimum draw (3 watts/ .5amp at 6 volts) during the winter months.

Even when we are open, using the phone wouldn't be common - it's more
of an emergency safety issue, so, I'd be surprised if we had 20 hours
per week at 6watts.

As I understand it, the 9 watt max is only used when running multiple
simultaneous conversations which will be relatively rare.

So, I think a 45 or 60 watt unit will be my choice to start.
I will try to get a bit of angle, though I want to minimize visual
impact and calling attention to the panels.

As someone suggested, we can swap in batteries or start a generator
when we have staff  there on weekends.

thanks again for all your help.
Phil

ps -
regarding this: >>So that means, as a minimum, assuming, let us say,
6W average requirements
that your panels need to have an output of 6 x 24 / 2.55 --> 56.47
W ...

I can see the math, but, how does that account for the fact that the
panels may not be a meter square and won't have 100% efficiency?









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