Date: 19 April 2016. Solar, Batteries
and an Inverter.
This was a
four-part series on solar power, battery storage and AC power used
aboard my boat. Sometimes I prefer smaller doses of information and
for those who do the separate articles are:
Batteries Store Power
Solar Makes Power
Power Used Aboard Seaweed
Inverters Make AC Power
This is the complete version with all the information contained in
the above four articles.
Solar, Batteries and an Inverter:
wrote asking about solar power. Like many I have embraced the solar
movement. The price has come down on the panels. Nothing moves so
nothing breaks. It is quiet. What solar panels are not is the
complete package. There's more to it.
with one 75 watt panel mounted over the cockpit in front of the wind
If you have the room for them, solar is definitely the way to
augment your power supply. I love mine. The one complaint I have
heard time and again is "I wish I had more
space for solar. I envy you folks with room for multiple panels."
A few years back I added two more
100 watt panels atop the pilothouse.
Aboard Seaweed I had a total of 275 watts. At that time I had four
100 amp batteries. The combination was not enough to run my
refrigerator 24/7 unless it was windy. Then the wind generator
kicked in enough power to put me over the top on power.
I like to make
more power than I use thus the batteries stay near full at all
Calder's it is best to use the least percentage of battery
Mini-Lesson on Power and Battery Capacity.
I'm going to use round
numbers for this explanation. It's easier for me to understand
Your standard *Group 27
or *Group 29 battery holds a certain number of amp hours aka
power. For math's sake, let's call it 100 amp hours per
battery. With the economical batteries (read: cheap) it is
suggested that we never use more than half of the amperage in
the battery. Thus our 100 amp battery is only going to provide
50 amps of usable power.
*Group 27 or Group 29
batteries: Batteries are numbered by the external size. Thus
a Group 27 battery will be 12 inches long, 7 inches wide
about 9 1/2 inches tall. A Group 29 battery is slightly
larger. Group 31's are 13" x 7" x 10". The capacity (number
of amps/power) does vary between brands.
I opted for the smaller
Group 27's. The larger batteries are way too heavy for me to
maneuver. The next time I buy more batteries I may chose
larger heavier ones as by then I shall be at the "hire
testosterone" stage of battery replacement. I won't be able to
lift them myself.
Each battery can only
be recharged a certain number of times before it fails.
There are tricks to rejuvenate batts though long term I have
not see a lot of success. It's easier to simply replace.
I do not
have the funds to continually replace batteries.
Calder's tome [Boatowners Mechanical and Electrical Manual
4th Edition] recommends we use a
smaller percentage of battery capacity. That will allow more
Each of my 12-volt batteries holds 100 amps of
power. I want to use the smallest percentage of amp hours
possible in order to have those batteries last. Here's a
use 125 amp hours per day in my life of decadence.)
*I rounded up to 150 amp hours per day in my chart to
account for the extras. Some days I might watch three
movies. Or use the microwave for lots of popcorn while
watching said DVDs. It's always better to estimate on the
higher side for usage.
Trust me when I say we
can always find accoutrements for a more decadent lifestyle. I
have never heard a boater say they had too much power
It is a good idea to have plenty of batteries. It is not just your
solar power generation that counts. We have to have a place to store
the power. That is the battery bank.
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.
I knew my refrigerator used a lot of juice aka
power. How much exactly was the question.
A Kill-O-Watt meter will tell you how much power your items consume. In
80 degree ambient temperature my reefer/freezer combination (the
smallest made, 3.1 cubic feet by Haier) requires 60 amp hours in a 24
Kill A Watt Electricity Usage Monitor
I bought this unit to
determine exactly how much power my cheap a/c powered
refrigerator uses. It provides power and time. From that it
was easy to figure out amps I need to supply each day for my
life of decadence.
Using solar power I know I
need to generate 60 amps per day to run the reefer.
This was the least expensive one I could find. It has the
fewest features. I don't need complicated.
The meter just needs to work.
Side Note: Online was far
less costly than in local stores which had the fancy ones.
Electrical gurus might want the information those provide. I
did not require more than the basics so opted for simple. J.
I generate 150 amps per day with my solar panels. The
refrigerator/freezer uses 60 amp hours during 24 hours. That leaves
me a theoretical 90 amps for everything else.
Definition of "everything else"
and power required per hour)
(4h @ 24w)
min @ 700w)
(24h @ 5w)
(10h @ .3A)
(24h @ 2.5w)
As you can see, when I add in the refrigerator/freezer (60A) I'm
using about 130A per day for my life. The microwave estimate
included a couple of bowls of popcorn plus reheating, tea making,
I need to make
that much power daily to support my life of decadence.
Could I use less power?
Absolutely. Do I want to? Nope. This is my home. I intend to live
forever aboard Seaweed. Having the accoutrements of a comfortable
life means that will happen. Those that have to "rough it" long term
are often left unhappy.
I am woman, over fifty and
appreciate things like ice cubes in my tea. A refreshing cool
tangerine (Cuties or Halo brands preferred) right from the reefer is
such a treat on a warm afternoon. Having lived without those things
makes me appreciate them all the more.
Would I go back?
No. Make that HECK NO! Life is great aboard my Seaweed.
Yes I am spoiled. And grateful, blessed, fortunate and so happy to
It's wonderful on the water...
When starting out you do not need to have Everything. What you do need
is a plan.
The plan for Seaweed included a wind generator and solar panels.
With the current solar panels (455 watts generating 150A per day)
I'm set. Life for me is no different at anchor in a remote cove than
it would be when tied to a dock with a power cord.
Actually it's better at anchor.
The only neighbors are fish, birds and dolphin. There is a
simplicity of life at anchor. Days start when I wake up. One day
that might be at 0400 and the next it could be nearly noon. This
retirement thing is Awesome!
To get where I'm at you're going
to have to buy some goodies though. You'll need solar panels, a
solar controller (it puts the correct voltage of power into your
batteries) and an inverter. An inverter turns DC battery power
into the stuff you use in houses: 120 volts of AC.
My second solar controller was a
About Solar Controllers: They are rated for specific
wattages. Originally with my 75 watt panel I had a Morningstar10. It
could have handled a 100 watt panel. The Morningstar30 shown above
would work fine for up to 300 watts. Later with the addition of the
two newest panels I upgraded to a MPPT60. It will support up to 600
watts of solar.
For further information on the
differences between the two types of controllers, the
(Standard vs. MPPT)
article would be worth a read.
Life is wonderful afloat. To keep up my standard of decadent living,
I need to generate just less than 150 amp hours per day. My solar
panels deliver that. The power is stored in my battery bank.
In order to use the power gathered by the solar and sent to
the batteries by the solar regulator I needed an inverter.
Originally I opted for an AIMS1000 from
The Inverter Store. It worked right well until I upgraded to a
You will discover
that each new addition brings unexpected consequences.
The desire for ice cubes meant a larger refrigerator. Then the
silverware drawer and those lockers needed to be removed for the
refrigerator. Details on the refrigerator install can be found in
Securing a Refrigerator (fans too)
Since the reefer was now in
there was a lovely (perfect really) spot for a microwave.
Then I tried the microwave with
my old-style inverter. The microwave didn't work. So I needed a
new and better pure sine wave inverter. And it will have to be
wired as it has some automatic switches in it...
You get the picture. Each change
though perfectly logical and sensible meant more complication and
bother. In the end it's worth it. In the midst it is definitely
Not to mention swapping engines
during the whole improvement fiasco.
It's good that I have a sense of humor and a dog. Skipper helped me
though the rough patches when my world was helter-skelter. New
friends and old were a serious boon.
I truly am blessed.
|Old and Ugly:
spiffy with a microwave too!
The new larger refrigerator is just perfect. With a
separate door for the freezer I can make ice cubes. I am
totally enjoying this upgrade.
Mini-Lesson on inverters: There
are two types of inverters. Square wave are the least expensive. I
have used a square wave AIMS1000 for years and it is a-okay. It
powered everything on the boat until I bought the digital microwave.
prices for inverters I have found is at
The Inverter Store.
The second type is a Pure Sine
Wave inverter. They are twice the price and if you need one, you
need one. Let me explain:
The pure sine wave units are the
best. They mimic exactly the power you get in houses. Pure sine
wave inverters will keep your electronics in tip-top shape. There
is virtually zero difference between the power they generate and
standard power found at a house.
will state unequivocally that the higher priced pure sine wave
inverters are best. They do not damage electronics and electric
items perform better with purse sine wave inverters.
The square wave work okay for
many things. Generally speaking, anything with a digital control
will not work with a square wave inverter. The type of AC power
cheap inverters produce is similar to but not exactly the same as
house power. Some stuff will work anyway.
Is it great? No, but the
square wave is Good Enough provided you have no sensitive items.
Mine did very well powering the computer, crock-pot,
refrigerator, and my Christmas tree lights.
Other items won't work. My
microwave makes a sound, the turntable spins and nothing heats up
when using the original square wave inverter. The square wave
inverter powers my a/c unit just fine. I suspect because the air
conditioner has a dial versus digital control, that is why the
inverter powers it without issue.
The microwave and my popcorn
Popcorn for One (and Stone-wave Update)
article] means I needed a Pure Sine Wave inverter.
My AIMS1000 I will pass along to another boater. It works, just
not for my particular application.
There are actually three types of inverters. Inverter/chargers are
also sold. I'm not fond of those. For me two separate units means
that when one part breaks I can simply replace the component. I have
a separate charger for the batteries when I'm tied to a dock.
Having real estate for solar is important. For those who have
limited space an expensive MPPT solar controller will increase the
power your solar panels put into the batteries. The less expensive
controllers work too. They are simply not as efficient as the MPPT
batteries through a solar controller. Batteries supply power to
inverter. Inverter changes battery power (12 volts) into AC (120
volt) power like you'd have in a house.
All three components have to work together.
Start small. Solar to batteries to 12 volt items.
THEN move up and start with your AC side of the boat.
The best visitors just want to sit
around and relax. They don't care what power system you have.
Note the Night Heron sitting on the rail of the boat
rafted next to me.
If you're like me you will find that buying a
cheap throw-away refrigerator for $150 is better economically than
spending $700 or more on a small 12-volt one. When mine quits I'll
go to Walmart and buy another.
Years ago (pulling on old-fogey slippers)
"everyone" switched over to 12-volt items. It was the "newest and
greatest" thing. We stopped using iceboxes (with blocks of ice) and
life was good. Then, well, things changed.
The DC refrigerators (reference Engel for
instance) are wonderful. They are also way beyond my budget. By
increasing gradually the amount of solar I have, I am now able to buy
and use any item off the shelf from regular stores such as Walmart.
I do not need to buy expensive "Marine" items.
BEFORE you spend the first dime however, make sure
you like life at anchor. If you're hopping from marina to marina
there is no need to expand your power creating beyond that of the
alternators on your engine. Solar is one answer for those of us who
prefer life off the grid.
I love the quiet, and I like my ice cubes too. You
really can have it all. It just takes work and determination.
This is the life:
P.S. - I am NOT a power expert. I'm relating the
experience I have had while out here for the past 8 years.
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 controllers.
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.
Do you use other means of power generation such as a
What provides the majority of your power when away from the dock?
Inverters Make AC Power ~
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