Subj : Solar TV Battery Test
To   : Nancy Backus
From : Barry Martin
Date : Sun Feb 02 2020 14:19:00


Hi Nancy!

Finally semi-tested the recharging of a 12v UPS battery using a solar 
cell charger.  -- Overall the run a TV off a 12v battery when the power
fails project.

In a word: failed.  Also have to add there are a lot of known details 
working against.  The project could work, just not here conveniently.  

Using an inexpensive 1.5 Watt solar battery charger; different one
from the one in the basement window (will go down and continue that clean
up project later).  Temporarily mounted it to the south-facing window up
here in the Computer Room.  A bit hazy out, but otherwise bright.  Sun
being filtered a bit through leafless tree branches.  Measured ~4 volts
-- we want 12 v!  And the manual says up to 24 volts!  (I can build
something to regulate down; technically I can up-convert too but there's
other losses.)

Later the Sun moved and essentially unobstructed: 7 v at noon.  Still 
insufficient.  

Several problems with the test setup:
 -- The window has 'UV Block'.  So do all the other windows in the house
    except for the ones in the basement.  
 -- Going through a window screen.  Keeps bugs out but doubt does that 
    much to sunshine.  Using this position because there's a screw hole
    at the window frame from the window air conditioner's side flaps: 
    used a wire clamp to keep the solar panel in position.  (Did test 
    later: moved to the top window: glass only, no screen.  Got less 
    voltage [!] but also the Sun had moved.)

Didn't try outside: warm enough today but in winter quite possible well
below freezing, could freeze and therefore break the battery.  Solar
cell outside, run wires to inside.... Thinking this is more of a
now-emergency than something planned and semi-permanent.


So appears the throw-it-together solar charging isn't going to work
here.  Do want to state I think solar works, just needs to be outside
and properly aligned.  The manual for this little portable critter even
says may need to realign 10ø.  Will discontinue the solar charger
option; will have to semi-plan ahead and maintain a battery or two to be
charged a different way, right now electricity.


                        ¯                          ®
                        ¯   Barry_Martin_3@        ®
                        ¯                 @Q.COM   ®
                        ¯                          ®


.... Useless Invention: Solar powered night light.
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