Advice on solar panels - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 27 Old 05-15-2011 Thread Starter
Senior Member
 
Join Date: Oct 2009
Location: Virginia
Posts: 1,302
Thanks: 3
Thanked 29 Times in 28 Posts
Rep Power: 7
 
Advice on solar panels

Here's the situation. I have a Catalina 34 with the basic Adler-Balbour refrigeration unit in my ice box. I believe my unit pulls about 3 amps when the compressor is running.
My house batteries consist of 4 x 6v batteries, each one putting out approx 230 amp hours.
I want to leave my icebox running Sunday night when I leave the boat and have it still on when I get back on Friday. Boat is unplugged so no battery charger is working.
I don't mind if my batteries run down some by the time I get back on Friday, but of course I don't want them dead either.
How big of a panel do I need to keep my batteries not necessarily fully charged, but still with a decent charge when I get back and turn on the charger?
When we get to the boat, it takes a good 24 hours for the icebox to get to a good temp. And then, 24 hours later, I'm heading home.
chuck53 is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 27 Old 05-15-2011
Junior Member
 
Join Date: Feb 2011
Location: s.f. bay
Posts: 15
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
solar

your a.b. draws 5.5 amps while running and usually runs 50% of the time, due to charging losses you probably need 100 watts. two 50 watters would probably be easier to place than one 100 due to smaller sizes. i purchased 50's from golden sun solar in brisbane ca. for 300 dollars for two, i think that is a very fair price. i actually bought six and now my problem is i can't use all the electricity i make!
tattoosteve is offline  
Quote Quick Reply Share with Facebook
post #3 of 27 Old 05-15-2011 Thread Starter
Senior Member
 
Join Date: Oct 2009
Location: Virginia
Posts: 1,302
Thanks: 3
Thanked 29 Times in 28 Posts
Rep Power: 7
 
Good advice, but I'm not so sure about the amperage draw. I switched off everything electrical on my boat except for my refigeration. My Zantrex monitor showed between 2.5 and 3 amps and I could hear the compressor running. Turned it off and it dropped down to 0. Turned it on and off several times and each time, my monitor showed no more than 3 amps. Is my Zantrex wrong or maybe I have a little smaller AB that uses less power than most.
chuck53 is offline  
Quote Quick Reply Share with Facebook
post #4 of 27 Old 05-15-2011
Senior Member
 
mitiempo's Avatar
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 7,665
Thanks: 0
Thanked 102 Times in 93 Posts
Rep Power: 9
   
At roughly 6 amps half the time your daily refrigeration draw is about 70-75 AH. You have 230 AH before your batteries are at 50% SOC. If you have 100 watts of panels you can count on up to 40 AH per day based on 5 hours of good sun per day. So on a sunny day you have a net deficit of 35 AH, as much as 75 on a rainy day. If the sun shines all week you will be ok but a few cloudy days and the batteries will be down more than 50% and their life will be shortened drastically.
Do you not have shorepower available?

Brian
Living aboard in Victoria Harbour
mitiempo is online now  
Quote Quick Reply Share with Facebook
post #5 of 27 Old 05-15-2011
Just another Moderator
 
Faster's Avatar
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 17,430
Thanks: 119
Thanked 385 Times in 365 Posts
Rep Power: 10
     
Quote:
Originally Posted by chuck53 View Post
Good advice, but I'm not so sure about the amperage draw....... or maybe I have a little smaller AB that uses less power than most.
Our A-B definitely runs between 5 and 6 amps when running, and is usually at an approx 50% duty cycle. If you have a newer one it may be more efficient. If indeed you only draw 3 amps when running you're well ahead of the game.

Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Faster is online now  
Quote Quick Reply Share with Facebook
post #6 of 27 Old 05-15-2011
Large Member
 
Join Date: May 2007
Location: Texas
Posts: 1,000
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 9
 
Do you keep things in the fridge during the week? Perhaps a 7 day timer could turn the fridge on the day before you need to use it. Eliminate most of your problem. A solar panels would still be a good addition but maybe not as elaborate.

I think the twin design might be a good idea too. Easier to mount and if one gets some shade on it, the other will still be producing.
mdbee is offline  
Quote Quick Reply Share with Facebook
post #7 of 27 Old 05-15-2011 Thread Starter
Senior Member
 
Join Date: Oct 2009
Location: Virginia
Posts: 1,302
Thanks: 3
Thanked 29 Times in 28 Posts
Rep Power: 7
 
Yes, I have shore power available but I prefer not to have the boat hooked up while I'm not there. The marina charges extra for boats hooked up all the time - no charge for typical weekend use.
chuck53 is offline  
Quote Quick Reply Share with Facebook
post #8 of 27 Old 05-15-2011 Thread Starter
Senior Member
 
Join Date: Oct 2009
Location: Virginia
Posts: 1,302
Thanks: 3
Thanked 29 Times in 28 Posts
Rep Power: 7
 
You know, that 7 day timer suggestion is worth looking into. Not sure how to go about doing that, but something I had not even thought about.

I'm not concerned about keeping food cold while I'm not on the boat. Just looking to have a cold (or semi-cold) ice box when I get there on Friday night.
chuck53 is offline  
Quote Quick Reply Share with Facebook
post #9 of 27 Old 05-15-2011
Junior Member
 
Join Date: Feb 2011
Location: s.f. bay
Posts: 15
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
solar

even in the s.f. bay i usually get more than 5 hrs. charging location is important of course but even at less than optimal you should get more than 40 amps per day from a 100 watt panel, having said that it is always better to have more, i have 300 solar and an airex wind generator so i could probably run an arc welder, but as a full time liveaboard/cruiser i want complete independence from shorepower. which means i would guess your needs aren't the same as mine, also just because your monitor says 3 amps doesn't make it so. practical sailor tested the a.b. and they say it draws 5.5 amps while running i would trust their estimate.
tattoosteve is offline  
Quote Quick Reply Share with Facebook
post #10 of 27 Old 05-15-2011
Senior Member
 
GeorgeB's Avatar
 
Join Date: Dec 2004
Location: Alameda, San Francisco Bay
Posts: 1,890
Thanks: 2
Thanked 57 Times in 56 Posts
Rep Power: 12
 
Chuck, what year (and sail #) is your Catalina? Mine is a MkII model (2000 - #1476). My A-B cycles @ 5 Amps/50% of the time as measured on my link 1000. My average electrical consumption is 2.5 Amps/hour. I'm wondering if your system isn't fully charged with freon? That could explain the "low" power draw of your compressor and that it takes 24 hours to cool down the refridgerator. Mine is cool after several hours. To accelerate the cooling process we do take a sack of ice down to the boat to get things started.
GeorgeB is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
solar panels GREGGWARREN Gear & Maintenance 3 08-27-2007 01:25 AM
Solar Panels bottleinamessage Jeanneau 0 08-16-2007 08:10 AM
solar panels rads Gear & Maintenance 1 10-25-2006 10:21 PM
Solar Panels sneuman Gear & Maintenance 3 09-24-2004 04:06 PM

Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome