Re: [Cerowrt-devel] solar wifi ap designs?

[Richard Smith <smithbone@gmail.com>]

On 06/13/2017 09:03 AM, Christopher Robin wrote:
> 
> On Tue, Jun 13, 2017 at 8:24 AM Christopher Robin <pheoni@gmail.com 
> <mailto:pheoni@gmail.com>> wrote:
> 
> 
>     On Tue, Jun 13, 2017 at 7:52 AM Richard Smith <smithbone@gmail.com
>     <mailto:smithbone@gmail.com>> wrote:
> 
>         On 06/09/2017 10:02 AM, Dave Taht wrote:
> 
>          > My use case used to be covering hundreds of km in the Nicaraguan
>          > jungle. The prototype for that covers a mere 110 acres in the los
>          > gatos hills, trying to get stuff deep into ravines and so on.
> 
>         Accounting for wost case is always what amplifies the
>         requirements of an
>         off-grid system.
> 
>         NASA Surface meteorology and Solar Energy claims that for Los Gatos
>         December is the lowest output.  Given a split-the-middle tilt
>         alignment
>         of 37 degrees it will receive average full-sun net of 3.5 hours.
> 
> 
> Dave: With these being tree mounted, how likely is full-sun? I'm not 
> familiar with the tree type/density. Are you're looking to avoid having 
> separated solar panels?
> 
> Richard: I would presume these calculations are all for "open field" 
> conditions?
> 
> If the panels are under a tree canopy, a lower attack angle may be 
> better to better utilize morning/evening sun. A higher one may be 
> necessary to get a useful charge during peak daylight. I've seen some 
> pretty impressive calculators to work out best guesses for field testing.

Yes.  All best case there.  Nothing fancy.  I was just trying to show a 
rough relation to the size of the system and uptime given crappy 
conditions without getting too complicated.  As you mention, figuring 
out the best setup can get pretty hairy.

Optimizing for in-tree use is left as a future exercise. :)

Optimum tilt for Dec is listed as 62 degrees but that only increases the 
full-sun from 3.5 to 3.9 so it doesn't change the analysis that much. 
Given there so much leeway in the peak months it certainly makes sense 
to be optimized for maximal production in the low months.

-- 
Richard A. Smith