Recommended Solar Panel..... - Page 3 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > General Interest > General Discussion (sailing related)
 Not a Member? 


Reply
 
LinkBack Thread Tools
  #21  
Old 03-14-2011
hellosailor's Avatar
Plausible Deniability
 
Join Date: Apr 2006
Posts: 10,711
Thanks: 2
Thanked 93 Times in 91 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
Cranking amps are for starting batteries. What you need to know is the "Group Size" of the batteries, or the Amp Hour capacity of them, nominally at the 20-hour discharge rate.

I'm guessing they are group 24 or group 27 with a nominal capcaity around 75AH each when new. If you only cycle them 50%, that means you are working around a 75AH useable capacity for the "bank".

How often you will draw them down, how fast you want to charge them...you have to run the numbers for an energy budget. Odds are that one 50A or 55A solar panel with a simple charge controller would work out pretty well for the minimal power needs you have. FWIW, if you invest in an MPPT controller, which may be overkill for you, they actually squeeze about 10-15% more effective power out of a solar panel, so they're actually useful.

Anything smaller, and a couple of gray days after a deeper than usual discharge is going to leave you looking for extension cords. Typically, in a full 12-hour day of bright sun, you'll get about four hours worth of "rated" full output fro a solar panel. (i.e. pretend the day is only 4 hours long but the panel is working at full output for those four hours.)
Reply With Quote Share with Facebook
  #22  
Old 03-14-2011
AdamLein's Avatar
Senior Member
 
Join Date: Nov 2007
Location: Coquitlam, BC
Posts: 1,866
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 7
AdamLein will become famous soon enough
Quote:
Originally Posted by MarkofSeaLife View Post
Also remember, when you are using power on your boat during the day you are still charging with your solar panel, so what you are using is 'free'. Your draw is only at night
That's a bit misleading. If you run a tiller pilot, start your motor, or whatever, during the day, those amp-hours have to be replaced, which delays the replacement of last night's draw.
__________________
s/v Essorant
1972 Catalina 27
Reply With Quote Share with Facebook
  #23  
Old 03-14-2011
SlowButSteady's Avatar
Senior Slacker
 
Join Date: Feb 2010
Location: SoCal
Posts: 4,223
Thanks: 0
Thanked 17 Times in 15 Posts
Rep Power: 5
SlowButSteady is on a distinguished road
Also remember that if you use your engine a couple of times each day you go sailing (in and out of the marina, and/or to anchor) you should probably run it at least 20 or 30 minutes or so each time you start it to get it up to full operating temp. In that case, once you've replaced the juice you used starting the engine, you'll be charging your batteries at a fairly high rate (probably something like 20-25 amps, at least. In other words, much of your electrical requirements will probably be met by the normal use of your engine.
__________________
Never forget them. Do something to prevent it from happening again.
Charlotte Bacon, Daniel Barden, Rachel Davino, Olivia Josephine Gay, Ana M. Marquez-Greene, Dylan Hockley, Dawn Hochsprung, Madeleine F. Hsu, Catherine V. Hubbard, Chase Kowalski, Jesse Lewis, James Mattioli , Grace McDonnell, Anne Marie Murphy, Emilie Parker, Jack Pinto, Noah Pozner, Caroline Previdi, Jessica Rekos, Avielle Richman, Lauren Rousseau, Mary Sherlach, Victoria Soto, Benjamin Wheeler, Allison N. Wyatt
Reply With Quote Share with Facebook
  #24  
Old 03-14-2011
Irrationally Exuberant
 
Join Date: Jul 2007
Location: Northern Virginia
Posts: 1,303
Thanks: 6
Thanked 6 Times in 6 Posts
Rep Power: 8
arf145 is on a distinguished road
I think it is being assumed here that you have these batteries set up, or switched, to run in parallel, meaning you have the amp hours of both available. Is that true? That will be important when figuring if you are going to be drawing them down by 50% etc.

There are a lot of threads here that cover this topic, if you can find them. Some good reading in there.
__________________
Tom K

2000 Beneteau 331
Northern Chesapeake Bay

Ambition is a poor excuse for not having enough sense to be lazy ~ Steven Wright
Reply With Quote Share with Facebook
  #25  
Old 03-14-2011
travlineasy's Avatar
Morgan 33 O.I. Perryville
 
Join Date: Dec 2010
Location: Maryland
Posts: 2,354
Thanks: 3
Thanked 63 Times in 53 Posts
Rep Power: 4
travlineasy will become famous soon enough
Just got a flier in the mail from West Marine for their Sunforce Solar Chargers:

125-mA - 1.5-watts - $17.49
350-mA - 5-watts - $49.99
1.0-A - 15-watts - $76.99

That translates to 30-percent off their regular price. That's a pretty good deal.

Gary
Reply With Quote Share with Facebook
  #26  
Old 03-15-2011
AdamLein's Avatar
Senior Member
 
Join Date: Nov 2007
Location: Coquitlam, BC
Posts: 1,866
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 7
AdamLein will become famous soon enough
Quote:
Originally Posted by travlineasy View Post
125-mA - 1.5-watts - $17.49

That translates to 30-percent off their regular price. That's a pretty good deal.
True but those panels are a bit small The cheapest one would take about six hours of full direct daylight to recharge a single AAA battery
__________________
s/v Essorant
1972 Catalina 27
Reply With Quote Share with Facebook
  #27  
Old 03-15-2011
Senior Member
 
Join Date: Aug 2009
Posts: 270
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 6
SpcAlan1 is on a distinguished road
I know the 15 watt version is about 2 feet long!
Reply With Quote Share with Facebook
  #28  
Old 03-15-2011
travlineasy's Avatar
Morgan 33 O.I. Perryville
 
Join Date: Dec 2010
Location: Maryland
Posts: 2,354
Thanks: 3
Thanked 63 Times in 53 Posts
Rep Power: 4
travlineasy will become famous soon enough
Keep in mind that the solar panels are not for charging your batteries from dead flat to fully charged. These panels do a great job of keeping your battery topped off and ready to go when you are. Most folks on this, and other sailing forms, are weekend warriors, sailing one or two days a week at most. The remainder of the time their boats are tied to the docks. I had the 350-mA charger on my Catalina 27 and it kept too dual purpose batteries fully charged all the time. In fact, this past winter I did not remove the batteries from the boat because the panel kept them fully charged. I checked them weekly with a hydrometer and the SG always read 1.275, which is right where it should be. And, the panel worked just fine on overcast days, times when there was no direct sunlight whatsoever. Granted, it didn't pump out the maximum wattage, but it still put something into the battery, which is better than nothing at all.

My panel was (is) mounted on the back rail on an adjustable frame that allows you to change the position so you get the best benefit from the sun at any time of year. It has a hermetically sealed connector where the wire plugs into the panel, and a pair of battery clips at the other end. About once a month I clean the batter clips with a bit of WD-40 and a piece of cloth. I also wipe down the battery terminals as well with WD 40 to insure good continuity.

Yes, the 15-watt panel is about 2-feet long, which is relatively small when you consider what it does. I suggest mounting the panel somewhere other than on a deck surface. Think about it. If you mount that panel where someone would normally walk, you know someone will likely step on it. If they do, that's the end of the panel. The adjustable, rail mount is the most likely candidate, particularly if it's mounted on a stern quarter.

Having sold my Catalina 27 just a few weeks ago, and the solar panel with it, I just ordered the 15-watt panel for my Morgan 33 O.I.. The Morgan has a pair of starting batteries, plus three golf-cart batteries connected in a series/parallel rig. I'm fairly confident the panel will keep them fully charged.

The boat also has a large, wind generator, but that will only be used while the boat is attended or underway.

Good Luck,

Gary
Reply With Quote Share with Facebook
  #29  
Old 03-15-2011
hellosailor's Avatar
Plausible Deniability
 
Join Date: Apr 2006
Posts: 10,711
Thanks: 2
Thanked 93 Times in 91 Posts
Rep Power: 10
hellosailor has a spectacular aura about hellosailor has a spectacular aura about
Those little panels, 15W and under, probably would be better marketed as "battery maintainers" rather than chargers. They're best suited for maintaining the charge on a battery, preventing the normal self-discharge that ruins batteries. And eventually, maybe, if the sun shines and battery is small enough, charging them too. :-)
Reply With Quote Share with Facebook
  #30  
Old 03-15-2011
AdamLein's Avatar
Senior Member
 
Join Date: Nov 2007
Location: Coquitlam, BC
Posts: 1,866
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 7
AdamLein will become famous soon enough
Hm... perhaps 15 watts could be enough. My first panel was a 7.5 watt panel that I kept on the deck and, as Gary predicted, sat on (not stepped on, sat on). So that's god advice there, as is the advice about regularly cleaning the connectors. Hadn't thought to use WD-40, though.

Still, last year I did a few 12+ hour singlehanded trips, so the tiller pilot tended to see some heavy use. I was happy to have the 30 W panel basically supplying its power for a good portion of the day and not have to worry about starting the motor (my batteries are also dual-use).
__________________
s/v Essorant
1972 Catalina 27
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
solar panel QuickMick Gear & Maintenance 11 12-11-2009 02:56 PM
solar panel alan_21_us Gear & Maintenance 12 07-31-2008 10:18 PM
B32 & Solar Panel Dcneuro Bristol 2 07-26-2007 10:56 AM
solar panel maestro Gear & Maintenance 3 11-20-2002 11:02 AM
Solar panel ldbarker Gear & Maintenance 3 10-27-2002 01:31 PM


All times are GMT -4. The time now is 08:41 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.