Date: 11 April 2016. Solar Makes
Power (Part II)
Part II, entitled
Solar Makes Power.
I now have a bunch of
solar panels and could not be happier. Recently I added two more 85
watt panels. They were a gift from Bucky. With the addition of those
two it matters not if I am at anchor or at a dock. Everything works.
Behind the solar panel there is an anhinga sitting on
a piling to the immediate left of my wind generator.
I now have a total of 445 watts in five panels
atop Seaweed. At this latitude with a plain old solar controller I
have about 150 amps of power incoming each day. Life is wonderful
figure out how many amps from each solar panel.
Here is a rough way to
figure out how much power your solar panel will produce: It's
all related to the angle of the sun, closeness to the equator,
and cloud cover. This is what I've found:
At the Florida/Georgia
border (latitude 30) using a standard solar controller (not
the more expensive MPPT controllers that are lots better) the
math works out thus: Take your wattage and divide by three.
Call it amps.
Of course if you are
closer to the equator you will have more hours of sun and thus
get more power from your panels. Conversely, if you are
farther away from the equator you will have few hours of
sunlight and thus will receive less power incoming.
It matters not if I am plugged into a shore power or at anchor. My
life is the same.
EXCEPT I cannot run the
wall-banger air-conditioner while at anchor. Well, actually I can
run the a/c unit though I must simultaneously run the engine. It
has to be mighty hot and muggy for that to happen!
One thing to remember is it is not just power generation you need to
deal with. You also must have a place to store the power derived
from solar, wind, etc. So as you are thinking about what you
require, also factor in batteries.
Aboard Seaweed I have 700+ amp
hours in seven batts. I get about 150 amps per day from my solar
panels. Additionally I have a wind generator that helps bump things
up too when the wind blows.
Note: It is never windy enough
if you are like me and anchor close to shore and in the lee of
islands. I prefer calm quiet anchorages to bumpy exposed places.
Note: This is a multi-part series about power for your boat's
goodies. It encompasses solar power, batteries and inverters. Part
Three, is next:
Power Used Aboard Seaweed.
The complete version with all the information contained in the four
articles is on this page:
Solar, Batteries and an Inverter,
the complete series.
Currently (April 2016) my
Comments are broken. Fortunately folks have emailed input, so
here you go:
From Cap'n Todd:
1. MPPT controllers - These
controllers are great IF you have multiple solar panels
wired in series. If you only have one panel or have your
panel wired in parallel there is very little benefit to an
MPPT controller versus the much cheaper PWM or simple on/off
2. Actually during the
summer we have more hours of sunlight up north than you do
down south. For example right now you have about 13 hours of
sunlight a day while here in Maine we have about 14 hours.
In late June we will have almost two hours more sunlight
each day than you do. The difference is in the sun angle
(ours is lower). That matters for horizontal fixed panels,
but in late June/early July we will not be far behind you in
power from our solar panels due to our longer days. If you
have solar panels that are angled to account for sun angle
(doesn't work on the hook), you can do better here than down
south during the summer. However, that requires an active
sun tracking system which takes power to run and will reduce
useable output and will break down now and then. It is an
option for the dock queen type boat, but not needed if there
is shore power available.
How many solar panels do you have aboard your boat?
Do you use an MPPT controller or the standard one?
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