On Fri, 9 Mar 2018 08:19:07 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Thu, 8 Mar 2018 08:16:06 -0500, "Jim Wilkins"
wrote:
...
The PS overloaded and shut off when I tried to charge a battery
directly with it. The series Schottky let it charge a battery
discharged to 12.02V. The low resistance I put in series wasn't
needed, but it might be with a more deeply discharged battery. I
want
this thing fully automatic in case the power returns in the middle
of
the night.

Indeed. You don't want dueling PSes on your hands.

The intent is for them to cooperate, with the higher of the two
outputs, PS or solar, charging the battery. The series diode keeps
higher voltage from backfeeding into the 13.8V PS and solar
controllers are built to accept battery voltage on their output when
their input fails.

How does this differ from the diodes attached to most solar panels
nowadays? You chose the exact schottky voltage you wanted?


I tested the concept with an old taper charger to which I added a
Variac to adjust the output, on a hazy day when the solar couldn't
quite keep up. The soft voltage/current knee of the taper charger
allowed the battery to drop more than the well regulated switcher
does. Perhaps today will bring enough sun to test the circuit before
more snow arrives.

Got preps? Somebody turned the storm cycle back on. Prolly that nasty
AGWK stuff, which means OMIGODWEREALLGONNADIE!


The Alpicool freezer current appears to average a bit below 1 Amp,
though the power meters I have now are sized for the 50A max of the
APC1400 and don't measure low currents accurately. The blue meter like
you have can be off by 0.2A. This is on order to hopefully make more
accurate Amp-hour measurements on lower powered devices and small
batteries such as Lithium 18650s.
https://www.amazon.com/Yeeco-Voltmet...ct_top?ie=UTF8

Added to my list. This is one of the few times that Amazon ($18.56)
vendors beat Ebay vendors ($23.35). The extra precision is needed for
the little guys, I see.

--
Silence is more musical than any song.
-- Christina Rossetti