Solar Power Question?

[mohave_steve]

I am considering placement of APs in locations that do not have utility power available. I am planning on placing 2-3 Powerstations at each location. The locations with 3 will also require a switch. I see from the datasheets that the PowerStations require 6.5watts @ 12v and I have found a switch that consumes only 2 watts. That tells me I need a power source capable of providing 13watts or 21.5watts 24x7.

21.5wattsx24=516watt/hr a day or 43amp/hr @12v.

I am planning on 100amp/hr battery and suitable solar capacity panel to run the system. The question I have is what capacity solar panel?

I spoke with a gentleman at one of the supply companies and was told that to support the 21.5watt load reliably that I would need almost 600watts solar panel capacity at a cost of about $4500.

600watts seems a bit excessive to me. Does anyone have any real world experience with this that may give me a better idea?

Thanks

Steve

[WHT]

$4,500 is in the neighborhood, +/- a thousand dollars.

Let's say it take X amount of electricity just to run your radios.

Over 24 hours it will take 24 x X amount of electricity.

Now you only have a typical four hour window (+/- two hours either side of high noon) that your solar panels can produce their rated output. That means they have to produce 4 x (24 x X) electricity in that four hour period for overnight operation.

Thats all assuming in never have cloudy skies for several days on end. But that may not be the case in winter. Solar power estimates usually figure on at least one day of sun every five days.

So on that one sunny day, you have a four hour window that you have to collect enough electricity to charge your batteries for the next 120 hours of inadequate sunlight.

[mohave_steve]

That makes perfect sense. Our "Solor Insulation" value here is around 4 during January. So I if the only output from the solar panels was Noon +/- 2 hours the figures would be on the money. However, the panels do produce power during a much broader period. Just not "Rated Power".
In a real world application what is realistic?

Sunrise at 7:00am & Sunset at 5:00pm. Near full output for four of the nine hours and reduced output for the other five.

[WHT]

The output starts to drop pretty fast once the sun starts moving off high noon. Some panels have a bubble fish eye lens array that can capture a wider angle.

[gobliners]

i am still a student and really interested in this topic..
i was just wondering is it practical to implement the transformers to boost up the current..
i hope experts could guide me..
tq..

[samcamfilms]

i am still a student and really interested in this topic..
i was just wondering is it practical to implement the transformers to boost up the current..
i hope experts could guide me..
tq..

good question!

[WHT]

Transformers don't boost or "increase" (in the sense of power) anything, they only increase or decrease the voltage an AC electricity.

You can use a transformer to increase an AC voltage and it "effectively" boost the power only in the sense that there is less voltage drop at higher voltages on long cable runs.

[sunwize]

It seems that your load is 8.5w @ 12vdc.
For a Mojave site that's about 100W of array and 120Ah of battery.
Keep it DC in solar.
Let me know if your interested in a system solution.
Regards,
Bob

[WHT]

http://forum.ubnt.com/forum/viewtopic.php?t=6551