Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 16-02-2009, 10:36   #1
Registered User

Join Date: Oct 2008
Location: STX
Boat: F31
Posts: 23
Solar Panel wiring/charging options

I'll be installing 2 panels (130-180w each) on our catamaran (4x 6V house bank). Because it is likely for some portion of one panel will be shaded during different parts of the day, my leaning is to wire these in parallel rather than series. I was planning connecting both panels to a 25amp blue sky MPPT charger and installing thier battery monitor option (as I don't have a Link or any other battery monitoring system).

Over the weekend I was talking with some solar instal companines and one chap suggested that I use 2 smaller charge controlers - one for each pannel - to maximize the benefit from the MPPT "voodoo'
", given that each pannel would have diffferent outputs at diffferent times of the day. My gut feel is that this guy was full of crap and that a single charger would just be reading the combined output of both panels and do fine, but I'm interested in others opinions of a dual charger setup. I could score 2 cheap chargers for less than the blue sky setup, but would still need a monitoring system.


IslandHops is offline   Reply With Quote
Old 16-02-2009, 11:17   #2
Registered User

Join Date: Jul 2006
Location: caribbean winter, Durango,CO summer
Boat: Nordhavn 5740
Posts: 455
Images: 4
Go with your gut feeling. IMHO there is no need to make the installation more complicated than necessary. Also, Blue Sky makes quality products, dont know about "cheap chargers". Go with the larget panels you can afford/fit. Can't have too much power.

gbanker is offline   Reply With Quote
Old 16-02-2009, 16:26   #3
Registered User
scotte's Avatar

Join Date: Apr 2007
Location: SF Bay Area, CA, USA
Boat: Privilege 39
Posts: 664
Originally Posted by IslandHops View Post
My gut feel is that this guy was full of crap
+1 on that. I'll be interested to see how you end up mounting the panels on your Privilege 39, we'll be doing the same next year on ours...
scotte is offline   Reply With Quote
Old 16-02-2009, 16:56   #4
Registered User

Join Date: Feb 2008
Location: Jacksonville FL
Boat: CSY 44' Grace
Posts: 46
Images: 1

If you go with two controllers you lose a lot of the magic. Most notable in your configuration:
The MPPT controller takes in a higher voltage from the panels run in series.
You can use smaller wire and lose less in resistance.
If one panel is shaded and the voltage goes less than your battery voltage it will still contribute any AMPS it creates using MPPT and panels in series.

I have an outback power controller and 2 200W panels. Works great. I get @ 45 V when it is running full out. The unit does not stop charging until it is almost dark out. I don't know blue sky but I have heard good things.
I tried having a bad day once - I did not like it.
peterroach is offline   Reply With Quote
Old 16-02-2009, 18:54   #5
Registered User
bill good's Avatar

Join Date: Oct 2006
Location: Brisbane Australia
Boat: Crowther windspeed 36' cat Goldrush
Posts: 700

I can't see any problems with one regulator & 2 panels in parallel. That will only result in the loss of power from the shaded panel. But I also would like to know what happens when two panels are in series & the same amount of shading occurs. I am about to install 2X 400watt 40v panels & the outback regulator. I am thinking 40v@10A is the safe bet but I am open minded. It is what will give the best result on the overcast day that I am still trying to work out.

Regards Bill
bill good is offline   Reply With Quote
Old 17-02-2009, 02:29   #6
Registered User

Join Date: Sep 2006
Location: Right now, Australia
Boat: Lagoon 420
Posts: 587
Images: 4
If you have panels with bypass diodes fitted you can run them in series quite happily as long as you're using an mppt to handle the voltage change. As soon as panels are shaded and become resistors, the bypass diodes allow the current from the active cells to flow past resulting only in the overall voltage dropping. I have 4 135W panels wired in series flowing into an outback mppt and it works a dream.

Dignity on the web
ess105 is offline   Reply With Quote

charger, 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Charging options captden Electrical: Batteries, Generators & Solar 5 01-07-2008 20:47
Does anyone have this solar panel? Chief Engineer Electrical: Batteries, Generators & Solar 7 25-04-2008 00:00
Winter Layup Solar Charging Sandero Electrical: Batteries, Generators & Solar 8 22-10-2007 08:36
Which solar panel??? marno Electrical: Batteries, Generators & Solar 5 02-08-2007 22:09
inverter to panel wiring jerry f Electrical: Batteries, Generators & Solar 8 26-06-2005 21:48

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 15:06.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.