Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 22-09-2009, 14:00   #1
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,369
10 Watt Solar Enough?

Is a little 10 watt solar panel enough to keep the batt's topped off while dry stored? 5 watt?
__________________

__________________
Cheechako is offline   Reply With Quote
Old 22-09-2009, 14:23   #2
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Trickle charger?
__________________

__________________
barnakiel is offline   Reply With Quote
Old 22-09-2009, 14:45   #3
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,369
Yea, just looking for something to keep em up for maybe as much as 6 months...
__________________
Cheechako is offline   Reply With Quote
Old 22-09-2009, 16:02   #4
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Look up Calder's book - he gives the proper size. Still I would think - how do we know how much sun there will be ??? So maybe just the bigger solar and a small solar regulator / rather than the smaller solar direct?

b.
__________________
barnakiel is offline   Reply With Quote
Old 22-09-2009, 16:05   #5
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,369
It's in Florida. There would essentially be no draw... everything off but the bilge pump, but the boat doesn't seem to accumulate any water now even in the torrential Fl rainstorms... yea I was wondering if using a 5 watt with no regulator would be OK... thought maybe someone out there has done this....
__________________
Cheechako is offline   Reply With Quote
Old 22-09-2009, 16:13   #6
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
I hope you get the answer by tomorrow. But if not, I will look up the book tomorrow (I have it in my friend's boat) and write up. The discharge is related to temp and the type of battery you have. And it cannot be done to gels.

b.
__________________
barnakiel is offline   Reply With Quote
Old 22-09-2009, 16:37   #7
Registered User
 
Portobello's Avatar

Join Date: Mar 2009
Location: Hobart
Boat: Portobello - a Walter Knoop designed "DOVEN 30"
Posts: 231
Images: 5
I have a 10 watt solar panel on my boat - our winters can be quite gloomy (especially the one just gone) and it keeps my batteries well topped up. We are 42 degrees south here so the winter sun is weak.
__________________
Love the journey!
Portobello is offline   Reply With Quote
Old 22-09-2009, 16:39   #8
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,369
you using a regulator?
I have two 8D batteries, wet cell.
__________________
Cheechako is offline   Reply With Quote
Old 22-09-2009, 18:17   #9
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
We used to use a 80 W solar into 160 Ah, no reg. But it was when cruising and then we used the engine only to make sure the engine was nicely oiled and ready. No other sources. Wet, deep cycle buckets.

In port it is different - the panel overcharges (as it well should). We disconnected the panel and plugged in the 4 stage (3 stage plus supply) charger.

I believe the discharge for normal (wet, deep cycle, not the newer low-discharge that you can buy from Vetus ao.) is up to 1% per day in hot climes.

This would call for 1 Ah daily charge per 100 Ah of the battery bank. If you consider a 4-5 hr sun it means 1/5 times 12 = 3 W panel (per every 100 Ah of battery bank). There is some loss too (and 12 Volt is not enough), so say 5 W.

But have you ever seen a say 5W panel with 36 cells ..... ???

So my way would be - a bigger panel with a regulator or a trickle charger from the shore.
__________________
barnakiel is offline   Reply With Quote
Old 23-09-2009, 05:32   #10
elf
Registered User
 
elf's Avatar

Join Date: Nov 2006
Location: North Carolina
Boat: Catalina 30
Posts: 105
We have a 10w panel that keeps our batteries charged just fine for months at a time here in NC.
__________________
elf is offline   Reply With Quote
Old 23-09-2009, 06:20   #11
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,586
Images: 240
Charge Controllers (voltage regulators) are not generally required on Solar Cells that produce less than 1.5 to 2% of the Battery’s Amp-Hour capacity, so an unregulated 10 Watt PV Charger will be acceptable on a battery as small as 40 Amp-Hour capacity.

A Flooded Lead Acid battery has a typical Self-Discharge rate of about 4% to 6% of Amp-Hour capacity per week. Accordingly, a 125A-H battery might self-discharge as much as 7.5 Amps/week.

Since a 10W solar panel might be expected to produce between & 10A 30Amps/week, it should more than suffice in maintaining a small battery bank.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 23-09-2009, 07:59   #12
Registered User
 
avril25's Avatar

Join Date: Jul 2009
Location: I live in Soutbridge, MA and Sail out of New Bedford
Boat: 82 O'day 25, Shadubie
Posts: 23
Images: 2
I have three solar panels for a total of 105 watts... two 125 amp hour batteries, lead acid type, and a charge controller. This set up has served me well all summer in sunny New England. I use my boat every weekend, lights, radios, dvd player, chart plotter etc with out thinking too much about it. by the time I leave for home, the meter is in the red. When I come back on friday night th meter is in the green. Lets do it again
I say....
__________________
avril25 is offline   Reply With Quote
Old 23-09-2009, 09:44   #13
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
As per Gord, just make sure you find a (so small a) panel that will deliver the trickle voltage - not easy if we are talking 5-10 W units.

b.
__________________
barnakiel is offline   Reply With Quote
Old 23-09-2009, 09:54   #14
Registered User

Join Date: Sep 2009
Location: Sweden westcoast
Boat: Allegro 33
Posts: 100
It works here 57N 58N to use solar in winter to keep batterries fresh and we do not have many hrs of sun in dead of winter. But Im not sure about capacity of cells or batteries./ Harry
__________________
Hurricane Harry is offline   Reply With Quote
Old 23-09-2009, 11:08   #15
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,369
any reason this wouldnt work? RAMSOND NEW 10 W WATT 10W SOLAR PANEL BATTERY CHARGER - eBay (item 400074089598 end time Sep-23-09 14:53:37 PDT)
__________________

__________________
Cheechako is offline   Reply With Quote
Reply

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
32 Watt Solar Panel CapnTony Electrical: Batteries, Generators & Solar 6 05-04-2009 11:49
FS: (2) 85 watt Kryocera Solar Panels benjiwoodboat Classifieds Archive 15 30-10-2007 08:26



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 21:50.


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.