Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 27-04-2011, 10:34   #16
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: 12,317
Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

I keep reading this thread and others like it so I will know what the answer is when it comes time for me to do it. But i tseems that it always comes down to a "it depends" answer every thread.

Would the choice between series or parallel greatly come down to the installation and location of mounting the panels? If always out in the open so low shading = series; and if on bimini or something that is going to experience a lot of shade = parallel?
__________________

__________________
sailorboy1 is offline   Reply With Quote
Old 27-04-2011, 10:47   #17
DoÖ or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by noelex 77 View Post
if one panel is shaded. MPPT does not fix the high resistance in a completely shaded panel.
If one can't find a good location for a solar panel, installing it in parallel to others so it doesn't hurt the output of the other panels is a way of looking at the matter that will be welcomed by the manufacturers. However, for the user it might be wiser to not invest any $$$ in panel(s) that don't produce due to shading.

In other words: if you only have 1 good spot for a solar panel.... install 1 panel. Do not waste money on panels that can only be installed in problematic locations where they will not produce or only produce a fraction of their potential.

Quote:
Is simplistic, naÔve, or just wrong.
Then you should re-read the posts about currents and voltages and loss in controllers. Those are wrong and me saying so can be called blunt or worse, but not any of the 3 terms you chose.

ciao!
Nick.
__________________

__________________
s/v Jedi is offline   Reply With Quote
Old 27-04-2011, 10:58   #18
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: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by Don Lucas View Post
I keep reading this thread and others like it so I will know what the answer is when it comes time for me to do it. But i tseems that it always comes down to a "it depends" answer every thread.

Would the choice between series or parallel greatly come down to the installation and location of mounting the panels? If always out in the open so low shading = series; and if on bimini or something that is going to experience a lot of shade = parallel?
Well Don It depends



Yes I think thatís a good summary, buts itís very complex to model.



With many boat installations a mixture of 2 banks in series then the 2 banks connected in parallel works best, but the 2 in series should ideally see similar amounts of shade Even better if you can afford 2 MPPT controllers that will track the MPP of the 2 banks separately.

Some experimentation under different conditions, before the wiring is finalized will provide the best answer.
__________________
noelex 77 is offline   Reply With Quote
Old 27-04-2011, 11:15   #19
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: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by s/v Jedi View Post
If one can't find a good location for a solar panel, installing it in parallel to others so it doesn't hurt the output of the other panels is a way of looking at the matter that will be welcomed by the manufacturers. However, for the user it might be wiser to not invest any $$$ in panel(s) that don't produce due to shading.

In other words: if you only have 1 good spot for a solar panel.... install 1 panel. Do not waste money on panels that can only be installed in problematic locations where they will not produce or only produce a fraction of their potential.
Ideally only panels that are in full sun all the time would be used, but this is just not feasible on most boats. Unless you have 64 feet to play with

Most installations, of multiple panels, have some that have shade and some that are in full sun. The panels that are in shade are not wasted because as the sun, or boat, moves the panels that were in shade and performing poorly will become the panels in sun that are performing best and vice versa.

The problem with the above situation is connecting the poorly performing panels in series with the panels that are performing well. This can in some situations drastically effect the output from the good panels.
__________________
noelex 77 is offline   Reply With Quote
Old 27-04-2011, 12:54   #20
Senior Cruiser
 
senormechanico's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Boat: Dragonfly 1000 trimaran
Posts: 5,830
Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by Don Lucas View Post
Would the choice between series or parallel greatly come down to the installation and location of mounting the panels? If always out in the open so low shading = series; and if on bimini or something that is going to experience a lot of shade = parallel?

That was why I suggested what I did.
__________________
Memento,homo, quia pulvis es, et in pulverem reverteris.
senormechanico is offline   Reply With Quote
Old 27-04-2011, 13:46   #21
Registered User
 
JiffyLube's Avatar

Join Date: Mar 2008
Location: Oceanside, Ca.
Boat: Islander Freeport 36
Posts: 567
Images: 8
Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by noelex 77 View Post
Ideally only panels that are in full sun all the time would be used, but this is just not feasible on most boats. Unless you have 64 feet to play with

Most installations, of multiple panels, have some that have shade and some that are in full sun. The panels that are in shade are not wasted because as the sun, or boat, moves the panels that were in shade and performing poorly will become the panels in sun that are performing best and vice versa.

The problem with the above situation is connecting the poorly performing panels in series with the panels that are performing well. This can in some situations drastically effect the output from the good panels.
I know almost nothing about this topic but I'm trying to learn and understand, so if my questions seem dumb please bear this in mind.

I'm just going to throw a couple of questions out there, and see what you guys can teach me.

If some panels will be in the shade and some not (depending on how they are wired together parallel or series) will one shaded cell in one panel pull all the panels down? Or only that one panel with a shaded cell?

Would it be good or bad to not wire the panels together but let them function on their own independent of the other panels?
__________________
JiffyLube is offline   Reply With Quote
Old 27-04-2011, 14:18   #22
CF Adviser
 
Bash's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: sausalito
Boat: 14 meter sloop
Posts: 7,260
Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by noelex 77 View Post

Most installations, of multiple panels, have some that have shade and some that are in full sun. The panels that are in shade are not wasted because as the sun, or boat, moves the panels that were in shade and performing poorly will become the panels in sun that are performing best and vice versa.
I couldn't agree more! My panels don't merely function as solar chargers. They also comprise my bimini, providing shade and weather protection in the cockpit. It cost me no more to build a solar bimini than it would have cost to build a fiberglass hard bimini. The later, however, would not have charged the batteries. Admittedly, I ended up going with more wattage in panels than I would have needed had I gone with something like a Solar Stik installation, but this was a concession I gladly made.

With my system, a parallel hookup makes all the sense in the world.
__________________
cruising is entirely about showing up--in boat shoes.
Bash is offline   Reply With Quote
Old 27-04-2011, 17:24   #23
֍֎֍֎֍֎֍֎֍֎

Cruisers Forum Supporter

Join Date: Apr 2006
Posts: 13,055
Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

Of course, if you get the masthead mount for a Solar Stik and get those panels up where they'll never be in the shade...VBG...
__________________
hellosailor is offline   Reply With Quote
Old 27-04-2011, 17:47   #24
Registered User
 
Aussie_Sequoia's Avatar

Join Date: Apr 2011
Location: New South Wales, Australia
Boat: Prout Event 34
Posts: 250
Send a message via Skype™ to Aussie_Sequoia
Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

Hello CF,

I've worked in the domestic solar industry for 15 years. The explanations about MPPT above are accurate - and it is very confusing if you are used to the old on/off type of regulator.

One thing I'd like to add is that unless you have an amorphous / thin-film type PV panel (such as UniSolar) then you have what is essentially a grid of cells all wired in series anyway.

Each cell produces about .5 volts (regardless of surface area) and are soldered together in series grids of (usually) 36 cells. 36 cells x .5 volts give is a nominal 18 volt output (of course open circuit can be a bit higher and on a load it is a bit lower).

The point is if ANY one of these individual cells is shaded, it will stop output from the panel. Now some newer panels have 'sub-series' wiring with by-pass diodes that allow you to take energy from different sets of cells - but not all panels and certainly not older ones.

This is a concern because of the probability of partial shading on a boat installation... and I would definitely not wire all of my panels together in series because if one of your 144 individual solar cells is in shade - you will get (ostensibly) nothing from the rest.

Just my 2 cents.
__________________
Aussie_Sequoia is offline   Reply With Quote
Old 27-04-2011, 21:13   #25
Registered User
 
west coaster's Avatar

Join Date: Nov 2006
Location: victoria, BC
Posts: 21
Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

Hi

Thanks for the great responses to my post.

clearly the choice between these three different combinations of 4 panels is not that straightforward.

someone peviously pointed out that 4 panels in series probably a no-go given the MPPT max input-side Volatge of 57 volts and a V(open circuit) of each panel of 20 volts. even though it probably wouldnt see the OC voltage, i agree and had already pretty much decided no on this. i also assume this arrangement would be most sensitive to shading of an individual panel or significant portion of the panel.

so its parallel, or series-parallel. i assume from the prior discussion that complete shading of a single panel would knock-out ca. 50% of the available power in the series-parallel arrangement, but only 25% in the parallel arrangement. it is likely that at least one panel will be shaded much of the time, so I am leaning toward the parallel only option if this makes sense.

someone also pointed out blocking versus bypass diodes. quite correct. the kyoceras actually have bypass diodes - this should protect them in a series arrangement with partial shading, no? also i assume the blocking diodes are unnecessary with a charge controller. kyocera documentation (e.g. http://www.kyocerasolar.com/pdf/KC40T-KC130TM.pdf) seems to confirm these two points.

i may try a experiment to compare the two arrangements with similar irradiance of the panels and blocking one half of a panel then one panel in the parallel and then series-parallel arrangemet. and checking the charge current on my link 20 battery monitor (which is ultimately what i'm trying to optimize) with the battery in similar states of discharge. I'll have to quickly rewire them to the alternate arrangement to ensure similar irradiance and make sure there is no cloud cover. if i do , i'll post the results.

thanks again.
__________________
west coaster is offline   Reply With Quote
Old 28-04-2011, 02:35   #26
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: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by west coaster View Post
Hi



so its parallel, or series-parallel. i assume from the prior discussion that complete shading of a single panel would knock-out ca. 50% of the available power in the series-parallel arrangement, but only 25% in the parallel arrangement.

.
The solar panels in shade wont be in complete darkness so the % reduction is not as great as you have indicated above, but the essential principle is correct even if the numbers are wrong.

Quote:
Originally Posted by west coaster View Post
Hi

. the kyoceras actually have bypass diodes - this should protect them in a series arrangement with partial shading, no? also i assume the blocking diodes are unnecessary with a charge controller. kyocera documentation (e.g. http://www.kyocerasolar.com/pdf/KC40T-KC130TM.pdf) seems to confirm these two points.

.
You do not need any additional blocking diodes. The Kyocera panels do have a large number of bypass diodes which does improve there shade tolerance particularly when connected in series with a MPPT regulator. The effect will depend on how much shadow is present, how deep is the shadow, and how many sub panels are effected.

Quote:
Originally Posted by west coaster View Post
Hi



i may try a experiment to compare the two arrangements with similar irradiance of the panels and blocking one half of a panel then one panel in the parallel and then series-parallel arrangemet. and checking the charge current on my link 20 battery monitor (which is ultimately what i'm trying to optimize) with the battery in similar states of discharge. I'll have to quickly rewire them to the alternate arrangement to ensure similar irradiance and make sure there is no cloud cover. if i do , i'll post the results.

.
That would be great. The information would be of interest to many people, itís a common question.
If you have the opportunity I would also be interested in difference bypassing the regulator (in parallel only obviously) to show how much gain the MPPT is producing.
__________________
noelex 77 is offline   Reply With Quote
Old 28-04-2011, 03:08   #27
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: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by JiffyLube View Post
I know almost nothing about this topic but I'm trying to learn and understand, so if my questions seem dumb please bear this in mind.[IMG]file:///C:/DOCUME%7E1/Skipper/LOCALS%7E1/Temp/msohtml1/01/clip_image001.gif[/IMG]

I'm just going to throw a couple of questions out there, and see what you guys can teach me.

If some panels will be in the shade and some not (depending on how they are wired together parallel or series) will one shaded cell in one panel pull all the panels down? Or only that one panel with a shaded cell?

Would it be good or bad to not wire the panels together but let them function on their own independent of the other panels?
There are no dumb questions on this subject. Its complicated. A lot of the information and data is from the domestic solar industry. They have the luxury of mounting the panels in a shade free place . When they talk about shade they are referring to clouds which will shade all panels reasonably evenly. Shadows on boats are very different, the mast or boom can cast a deep shadow on only some of the panels.
When there is debate about fundamental questions such as series or parallel connection it indicates there is a lot to learn. As the boat solar market is small I think boat owners themselves are going to have to do some of the basic research.

To answer your question shade on one panel will reduce the power produced by that panel and the reduction will be a lot more than you would expect from the surface area of the panel.
Other panels connected in parallel will be unaffected by the shaded panel and will still deliver there full power.
Panels can only be connected in series with a MPPT regulator. Panels in full sun connected in series to a shaded or partially panel can be effected. Depending on the degree and amount of shade the power from the good panel can be drastically reduced, in some situations it is not effected much and in other situation the MPPT controller can extract slightly more power from the shaded panel when it is connected in series.
In other words panels in series with a MPPT can produce much less power or a bit more.
Once the voltage of the solar panels is well above the battery voltage there are no further possible gains from series connection and the risks of losses increases with every panel added in series. So there is no advantage in connecting more than 2 (nominally 12v) solar panels in series (There is a very slight possible gain from a reduction in wire losses, but this is small on the short runs found on a boat)
__________________
noelex 77 is offline   Reply With Quote
Old 02-05-2011, 22:03   #28
Registered User

Join Date: Jan 2011
Location: Socal
Boat: J/37
Posts: 42
I will be using the same panels but only 2 of them, I will be connecting in parallel to my battery bank, 4 lifeline agm group 31 and a similar agm though I cant remember off hand which, starting battery , and I was wondering what I should use for a charge controller?

Thanks
__________________
Thank you dad is offline   Reply With Quote
Old 04-05-2011, 19:08   #29
Registered User

Join Date: Sep 2010
Location: Eastern Shore, MD
Boat: Catalina 350
Posts: 69
Lightbulb Re: 4 Solar Panels: Parallel, Series, or Series-Parallel

Quote:
Originally Posted by Aussie_Sequoia View Post
Hello CF,

The point is if ANY one of these individual cells is shaded, it will stop output from the panel. if one of your 144 individual solar cells is in shade - you will get (ostensibly) nothing from the rest.
This was my Ah-Ha monent. I was initially thinking the solar panel as a varistor. Now, I see it can be an open circuit! I plan to mount my panels above the bimini on a mount and below the boom. From, my initial reading, I was thinking 2 big panels in series since they will get the same sun less the boom shading. That should not be a problem? The boom could not take more then 10% away from one panel. Wrong!

I think the key will be to look for the maximum amount of subgroups or bypass diodes in a single panel. Or, go for 4 panels with the maximum subgroups.

Thanks! That was a great discussion. At least I think I know what direction to head.
__________________
Windseeker is offline   Reply With Quote
Old 04-05-2011, 20:00   #30
Registered User
 
Aussie_Sequoia's Avatar

Join Date: Apr 2011
Location: New South Wales, Australia
Boat: Prout Event 34
Posts: 250
Send a message via Skype™ to Aussie_Sequoia
Re: Four Solar Panels: Parallel, Series, or Series-Parallel

Glad to help. Now there may be people with more boat-specific experience than me who say it doesn't shut down completely (I've read 50% above?) but this is due to varying degrees of shade and sunlight. I stand by my statement and challenge anyone to place their hand over a single cell (touching the glass) and watch their voltmeter drop to nothing. This is of course unlikely to happen in reality... but I was just trying to explain how the cells work together in series.

I think your final plans sounds very good. Let us know how it turns out.
__________________

__________________
Aussie_Sequoia 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


Similar Threads
Thread Thread Starter Forum Replies Last Post
600 Watt System - Series , Parallel or Combination ? SeaKing Electrical: Batteries, Generators & Solar 2 24-05-2011 09:15
Solar Panels Wired in Series / Parallel SailFastTri Electrical: Batteries, Generators & Solar 6 04-08-2010 07:51
Connect Solar Panels in Series or Parallel? gandalf Electrical: Batteries, Generators & Solar 2 27-01-2010 20:04
Series/Parallel Wiring for 24Volt Pelagic Electrical: Batteries, Generators & Solar 17 12-09-2008 21:00
How to wire solar panelsL Series or Parallel? CSY Man Electrical: Batteries, Generators & Solar 23 18-08-2007 16:42



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 00:35.


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.