Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 15-08-2012, 06:16   #1
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,336
How Much Solar

How much solar do you have, is it enough?

Lets stay away from theory and responses that have to do with doing a demand calculation etc as we all know that theory and reality don't always match. I've calculated mine till the cows come home but that doesn't mean the answer is real life correct.

Just how much solar do you have, what size loads do you have, is your solar keeping up?
__________________

__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is online now   Reply With Quote
Old 15-08-2012, 06:24   #2
Registered User
 
denverd0n's Avatar

Join Date: Jun 2008
Location: Tampa, FL
Posts: 3,954
Images: 6
Re: How Much Solar

Demand calculations ARE reality. Or at least, as close as you can get without extensive and expensive trial and error experimentation.
__________________

__________________
denverd0n is offline   Reply With Quote
Old 15-08-2012, 06:30   #3
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,394
Re: How Much Solar

Within reason and without getting too crazy about it I would install as much solar as I could afford and have places to comfortably put it. That would give you the extra capacity for those cloudy days with reduced solar output.
__________________
The water is always bluer on the other side of the ocean.
skipmac is online now   Reply With Quote
Old 15-08-2012, 06:36   #4
Senior Cruiser
 
Sailmonkey's Avatar

Cruisers Forum Supporter

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 5,793
Re: How Much Solar

We've got two panels, for a total of 135 Watts. I don't plug the boat in while docked except to run the air cond, and have no battery charger. We have an Isotherm midget refrigerator in a small (3-4 cu ft) box with mediocre insulation. With 460 AH of batteries I can leave the fridge on for weeks at a time and the batteries are almost always at 100%. While cruising the panels keep up with all the normal house loads, The 200 watt wind generator is to run the watermaker and supplement the charge from the solar panels.
__________________
Sailmonkey is online now   Reply With Quote
Old 15-08-2012, 06:36   #5
Registered User
 
GeoPowers's Avatar

Join Date: Dec 2008
Location: Gulfport, MS
Boat: Beneteau 393
Posts: 947
Images: 27
The first two posts kinda say it all, but to answer you specifically I have 450w and it runs everything (DC and AC) except hot water and air conditioning. Family of four living aboard. Don't know about wintertime outputs yet, just installed it a few weeks ago.

If you're not going to go to the effort to figure out your electrical demand and power needs, just put up as much solar as you have room for using the most efficient panels you can find.

Frank
GeoPowers is offline   Reply With Quote
Old 15-08-2012, 06:39   #6
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 8,583
Images: 14
Re: How Much Solar

125w will support us at anchor for over 5 days in strong sunlight. Usage is fridge, laptops and lights etc so 30 - 40 AH a day from 220AH house bank. We start going negative when it's cloudy though. However, running the webasto heating takes its toll with an extra 40 AH each night.

Pete
__________________
Moody 31 - April Lass
Pete7 is offline   Reply With Quote
Old 15-08-2012, 06:40   #7
Moderator
 
noelex 77's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: Living on dirt waiting for our new yacht to be built.
Boat: Half built Bestevaer.
Posts: 10,619
Re: How Much Solar

The calculations usually work out quite accurate, but some real world examples are a good idea.

330w of solar.

Run all the normal stuff plus small Watermaker. In the Med heaps of power in summer, but need to careful in the winter and often don't run the fridge. It's cold enough already.
__________________
noelex 77 is offline   Reply With Quote
Old 15-08-2012, 06:55   #8
Registered User

Join Date: Mar 2007
Location: On the hook in Florida
Boat: Tayana V42 - Passages
Posts: 504
Re: How Much Solar

Consumption is a bit over 100AH daily. Big reefer and freezer with holding plates. 390 watts of panels on an MPPT controller keeps up in Florida and the Bahamas.
__________________
Trying to live on 20th century money in the 21st century.
jcapo is offline   Reply With Quote
Old 15-08-2012, 06:59   #9
Registered User

Join Date: Jul 2006
Location: Underway in the Med -
Boat: Jeanneau 40 DS SoulMates
Posts: 1,905
Images: 1
Re: How Much Solar

we put on 395w and are thinking about one more 135w panel if the structure to hold them will take it and i can afford it - we have been in the carib for a couple of years and as long as the sun shines it is great - we run reefer, computer, fans, insturments, water maker, ect -

just our thoughts
chuck patty and svsoulmates
in trinidad for hurricane season
__________________
chuckr is offline   Reply With Quote
Old 15-08-2012, 07:09   #10
Marine Service Provider
 
Azul's Avatar

Join Date: Jun 2012
Location: Beaufort, NC
Boat: 1968 Cal 34, 1984 Catalina 22, 1987 Sanibel 18, 1968 Tanzer 16, 1989 BW Outrage 19, BW SS 15
Posts: 525
Images: 2
Re: How Much Solar

Thanks for putting this idea out there Don! Many of us are afraid to ask a dumb question in fear of the "why not hit search" answer. I have read all of the house battery bank/charge controller/best solar panel/bimini solar panel mounting/ad nauseum calculation threads- even that RV Bob guys blog and I still feel a little lost as to how to get started. It seems some people have 290 W of panels and have trouble running their mast head light and a fridge that will only hold a six pack while others have 960 AH of batteries, 24 panels and can even run a washing machine but they have $5000 worth of parts and an engineering degree. Very confusing. Perhaps someone can suggest a system that can be augmented as time/money/need increase in a stepwise fashion for those of us that don't completely understand the difference between amp hours and wattage. For example: Buy two deep cycle batteries for a total of 290 AH at Wal-Mart because they have a 3 year warranty if you fry them, A Guest battery 1/2/off switch, one or two 145 W panels paying less than $1.25 per watt with shipping if you have room to mount them, a $50 PWM charge controller (you can replace later with a $600 model) set to charge your batteries to at least 14.8 V if not 15.5, some sort of battery monitor you can use to figure out in real time what is really going on when you discharge your batteries to 50% by hooking up a 54 inch tv and playstation etc. In reality, my boat came with radar (that was never taken out of the box,) and I would like to have a little fridge/freezer as my two big drains.
__________________
Azul is offline   Reply With Quote
Old 15-08-2012, 07:30   #11
Registered User
 
Sluce's Avatar

Join Date: Jun 2009
Location: Salem harbor, MA
Boat: Nordic 40
Posts: 57
Re: How Much Solar

We have an 185W panel mounted on the dodger. It is great for weekend use. The batteries are always topped off when we get to the boat. It isn't enough to keep the fridge going full time though. Admittedly it is a very old and inefficient fridge.
The long term plan is new fridge, new and bigger battery bank, and two more panels mounted on the bimini. My feeling is once we have enough power to meet our calculated demand we will get spoiled and find something new to add to it. That has certainly been my past history.
__________________
Sluce is offline   Reply With Quote
Old 15-08-2012, 07:38   #12
mrm
Registered User

Join Date: Feb 2011
Location: Poland, EU
Boat: crew on Bavaria 38 Cruiser
Posts: 651
Re: How Much Solar

Quote:
Originally Posted by denverd0n View Post
Demand calculations ARE reality. Or at least, as close as you can get without extensive and expensive trial and error experimentation.
+1

Besides, it depends on average weather patterns of chosen cruising area too. However, to try answer the OP question with a very very rough ballpark estimate, install 4 * X Watts [W] of solar panel power, where X is your average daily consumption in Ampere hours [Ah].

If you don't know your daily consumption or can't be bothered with math the answer is even simpler: install what you can afford and have space for and live with it.
__________________
mrm is offline   Reply With Quote
Old 15-08-2012, 08:08   #13
Commercial Member
 
Mark Johnson's Avatar

Cruisers Forum Supporter

Join Date: Sep 2009
Location: New Bern NC
Boat: Searunner 34 Trimaran
Posts: 1,565
Re: How Much Solar

Quote:
Originally Posted by Don Lucas View Post
How much solar do you have, is it enough?

Lets stay away from theory and responses that have to do with doing a demand calculation etc as we all know that theory and reality don't always match. I've calculated mine till the cows come home but that doesn't mean the answer is real life correct.

Just how much solar do you have, what size loads do you have, is your solar keeping up?
The demand calculation is a cinch. First, equip the boat from stem to stern with a small, "energy efficient" version of what you want. LESS IS MORE... The differences are astounding, and add up! Then, just live on the boat, anchored out, for a few months. If you will be anchored out 90% of the time, and at sea for about 10%, (like most cruisers), then that's your "need", 90% of the time.

You want a battery bank large enough to only be down by about 20% in the morning, and a solar array that is "twice as large" in Ah produced on a good day, as the (90% of the time) need. Most folks do this all wrong, and most books on the subject suggested it to them!

This way, you will "usually" be back to 100%, with a 3 stage regulator, by about 11:00 AM! On VERY cloudy days, 100% will take most of the day, but you'll get there.

The advantage of this is that your devices will work better and live longer, (with the higher V), and your batteries can last 15 years!

In the big picture / long haul, it is cheaper to spend your money on extreme energy conservation, as well as a large solar array and battery bank, (like Trojan L-16s), than any other route. With ALL of the standard tricked out accouterments aboard, we have gotten our normal need down to about 40 Ah per day. (Twice that at sea) If you use much more, well, there is no need too...

When at sea, and your consumption doubles. For that 10% of the time, you run the engine for 45 minutes just before sunrise. This generator time is when the batteries can accept it best. Then, over the day, the solar can do the last half of the charge. You still get to 100%, and the engine just got a little morning workout, consuming very little fuel.

!00% solar, 90% of the time, with extreme reliability... works great, is practical, and easy to achieve.

This is based on decades of this very routine...

Mark
Attached Thumbnails
Click image for larger version

Name:	P8290437 (2).jpg
Views:	129
Size:	414.0 KB
ID:	44933  
__________________
"Let us be kind to one another, for everyone you meet is fighting a hard battle".
Mark Johnson is offline   Reply With Quote
Old 15-08-2012, 08:22   #14
Registered User

Join Date: May 2009
Location: Massachusetts
Boat: 40' Silverton Aftcabin with twin Crusaders
Posts: 1,590
Re: How Much Solar

Quote:
Originally Posted by mrm View Post
+1

Besides, it depends on average weather patterns of chosen cruising area too. However, to try answer the OP question with a very very rough ballpark estimate, install 4 * X Watts [W] of solar panel power, where X is your average daily consumption in Ampere hours [Ah].

If you don't know your daily consumption or can't be bothered with math the answer is even simpler: install what you can afford and have space for and live with it.
Good reply, the best of which notes location, location..... Places such as Florida are overwhelmed with the sun whereas here in Massachusetts there are always some clouds and many of them from airplanes, yes airplanes. Long after a plane passes, you can still see a long ribbon cloud from its exhaust.

This week I installed a pair of DM 145W panels I purchased from Amazon delivered for $320. I also purchased a Morningstar ProStar 30 PWM converter. I am into my second full day with the panels which began with heavy clouds, thunder storm followed by rain and now the sun is trying to show itself. As I type I read 5.8 amperes charging my batteries. My high yesterday was about 11 amperes. If I had great sun, maybe I could have gotten closer to the max of 16 amperes.

I saw my current change yesterday from around 4-5 amperes at 9am gradually rising up to 11 amperes around noon, later diminishing.

I am leaning towards adding another set of poly panels from Amazon when they are restocked. As others have mentioned, use as many as you can afford matched with the available space.

Foggy

EDIT:

I have a Xantrex 1250 or 5012 whatever battery charger for my 4 each (two banks) 6 volt 230AH Penn batteries plus a Freedom 1KW inverter/charger for my 24vdc bank which is used for lighting, TV, Microwave. The batteries that get punished are the 12 volt banks mainly because of refrigeration. We have an 8.3 Summit fridge with self defrost, great fridge but consumes a lot of power.

Typically I run our generator 2 hours in the morning and 2 hours at night. Yesterday I began the day without charging the 12 volt banks and only charged the 24 volt bank for 1 hour.

After running the genny for 1 hour this morning, the 12volt banks are fully charged or as full as the Xantrex is going to get them. Charging current from it is down to 6 amperes. The 24 volt bank looks like it is going to require another full hour to complete its charge.

Summary (as it looks) I cut my genny time charging the 12 volt stuff from 4 hours to 1 hour/day. The 24 volt stuff which has no solar, still requires about 2 hours of genny/day. Hope this helps--
__________________
foggysail is offline   Reply With Quote
Old 15-08-2012, 08:49   #15
Registered User
 
neelie's Avatar

Join Date: Oct 2007
Location: On the boat
Boat: Valiant 50
Posts: 514
Re: How Much Solar

Quote:
Originally Posted by mrm View Post
+1

If you don't know your daily consumption or can't be bothered with math the answer is even simpler: install what you can afford and have space for and live with it.



Doing the load calculations presumes you have the space and can afford whatever PV outputs your calculations come up with - this may not be the case.

Do as mrm suggests, see what kind of real world output you're getting and then adjust your usage, and system efficiency to balance. In essence, this question is quiet profound, and has more to do with lifestyle adjustments as far as power consumption goes in the future.
__________________

__________________
The light at the end of the tunnel are no longer the headlights of the oncoming train......yippee
neelie is offline   Reply With Quote
Reply

Tags
solar

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 16:17.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.