We have an AC coupled backup system at our house
in S.E. Ohio. In the winter we have many cloudy
days. We are using two 40 W Sunwise modules in
series with a Morningstar PWM CC to maintain a
415 AH, 24 V set of Full River AGM batteries. We
don't need to use the AC charger for around 1/2
the year. In the winter, we charge regularly from the grid.
Colorado has a lot more winter sun that SE Ohio.
If I did ours over again, I'd double the
maintainer array. But we have many periods, of
several days in a row, where it is so dingy that
our main array produces almost nothing, with no
snow cover. I've never seen these prolonged, low
light conditions in Colorado. If the price
difference for a larger maintainer array isn't
too much, I'd likely go bigger, especially since
your battery bank is twice as big.
Drake Chamberlin
Athens Electric LLC
OH License 44810
CO License 3773
NABCEP Certified Solar PV
740-448-7328
<http://athens-electric.com/>http://athens-electric.com/
At 11:19 PM 10/8/2018, you wrote:
Lots of questions this season..... I'm
winterizing a cabin for a customer that will not
be there for the next 8 months (summer use
only). Inverter and loads will be off. The
rooftop array will probably be covered with snow
for extended periods of time, and he has a brand
new 800 AH set of AGM batteries. I've read
that AGMs can handle sitting for longer periods
of time, but my experience is that they are a
bit finicky. I'm planning on adding a small
wall mounted array on a small Morningstar PWM
controller that's sole purpose is to trickle
charge the batteries and off set the self
discharge in heavy snow. What is the minimum
size array needed? I've calculated self
discharge rates from 2% to 5% /month, and I'm
seeing a very small array would offset
that. Even at 5% monthly losses, and 4 hrs of
sun/ day, I'm seeing a 10 watt array could meet
that. My current plan is a pair of 30 watt
modules wired in series for the 24 v
battery. Is that too small? Or should I not
even worry, because enough sun will creep
through the snow to the main array? Thanks, --
Ray Walters Remote Solar 303 505-8760
_______________________________________________
List sponsored by Redwood Alliance List Address:
[email protected] Change
listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://www.mail-archive.com/[email protected]/maillist.html
List rules & etiquette:
www.re-wrenches.org/etiquette.htm Check out or
update participant bios: www.members.re-wrenches.org </x-flowed>
_______________________________________________
List sponsored by Redwood Alliance
List Address: [email protected]
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://www.mail-archive.com/[email protected]/maillist.html
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out or update participant bios:
www.members.re-wrenches.org
