Somewhere in the archives of this list, I posted a spreadsheet designed for 
very high reliability  in northern climates.   

WRAP boards consume about 1A @12V. 

That's 24AH per day. 

Depending on your location, your WORST month's solar power capability will 
range from minimal to around 4 hours / day average.   

Thus, if are southern coastal, you can count on around 4 hours of sun per 

So, you need 24 AH 
divide by 4 hours of sun average 
6 amps needed for 4 hours. 
2 Kyocera KC65T's are 3.6 amps ea 

Now, you need batteries.  First, estimate your longest possible period 
without full sun...  3 days?  5 days?  10 days?   

for me, I had figured 10 days. 

So.. 10 days X 24 ah = 240 ah.  Since you should not discharge more than 
50%, i'll need 240 / .5 or 480 AH of battery c apacity @ 12V.  That way, 
even long term weather won't damage the batteries. 

Your solar panels should go in series, with one of these: 

It makes the panels a LOT more efficient and produce considerably more 
power over the long term. 

Now, if you use the logic and formulas here, you should be able to roughly 
calculate for any size load and location.  Use "insolation" charts for your 
location.  They come with w/m ratings, and fortunately, those happen to be 
roughly equivalent to sun hours per day. 

On Sun, 4 Feb 2007 15:40:43 -0600, Mark McElvy wrote 
> I am trying to wrap my head around calculation power consumption 
> and run time calculations. I used a Kill-A-Watt, plugged in a WRAP 
> board w/ one each CM-9 and WLM54g. The CM-9 is the backhaul and 
> WLM54G is the AP with two clients connected. The following data 
> was collected. 
> 330 Hours 
> 1.85 KWH 
> ..07 A 
> 05 WATT 
> 07 VA 
> I could use some help deciphering. 
> I need to understand battery capacities and how to calculate run times 
> based on the above info and a given battery size. Also charging 
> with solar, how to calculate charging capacity needed. 
> Mark 
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mark at neofast dot net 
neofast, Inc, wireless internet for the Walla Walla Valley and Blue 

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