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Author Topic: Adding a Third Solar Panel: Parallel or Series?  (Read 1073 times)

DesertMax

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Adding a Third Solar Panel: Parallel or Series?
« on: June 11, 2016, 07:45:50 PM »
Often when I have asked this sort of question I get so much technical jargon which I don't understand that it does not help me at all.
I understand the difference between P & S, just need to know what the best choice is for my situation.

Here is what I have: new rig came with 2 Siemens M75 panels.  Here is a shot of the sticker on the back of the panel :::
 (http://i.imgur.com/1bygx3Rl.jpg)

My one panel I want to add is also a Siemens but an M55 & not rated exactly the same :::
(http://i.imgur.com/rRMqrvEl.jpg)

I am not looking for a perfect system right now and just need to get this done on a schedule for now.  Will be tweaking it later after leaving here.


kdbgoat

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Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #1 on: June 11, 2016, 08:56:56 PM »
If hooked in parallel,  shadows or dirt on one panel will not affect the output of the other panels. It will affect output of all panels in series.
I know you believe you understand what you think I said,
But I am not sure you realize what you heard is not what I meant


2016 Leprechaun 319DS

DesertMax

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  • Posts: 74
Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #2 on: June 11, 2016, 10:33:04 PM »
How nice to get what I asked for..  a straight forward concise & understandable answer I can use..  Thank You...

Lou Schneider

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Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #3 on: June 12, 2016, 01:50:53 AM »
In parallel, the currents of all the panels will add while the voltage stays the same.  In series the 3 panels will produce 50-60 volts and you'll need a MPPT tracking solar controller that can handle this voltage and convert it down to an acceptable level.

I also recommend a parallel connection assuming your two existing panels are likewise connected in parallel.  Which they are, unless you have a custom installation using an MPPT (Maximum Panel Power Point) controller.
« Last Edit: June 12, 2016, 01:55:45 AM by Lou Schneider »

kdbgoat

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Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #4 on: June 12, 2016, 05:23:55 AM »
If you're not real familiar with solar power,  I would suggest googleing "Jack Mayer" and "Handy Bob". There's a lot of good information there.
I know you believe you understand what you think I said,
But I am not sure you realize what you heard is not what I meant


2016 Leprechaun 319DS

DesertMax

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  • Posts: 74
Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #5 on: June 12, 2016, 05:46:36 AM »
Thanks to all for the great responses..

DesertMax

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  • Posts: 74
Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #6 on: June 13, 2016, 02:49:16 PM »
Hi Guys, ok now I have another question in the realm of caution :::
I am soon ready to install my 3rd panel and this is what we call a "new construction" installation.
There is no template and there are no holes to simply drop screws back into...

I know I know I'm a solar rookie but hey I'm having fun with it.. 
So the highly predictable question is what precautions if any can I take so I don't hit electrical wires
or anything important that I shouldn't hit? 
The position I like has no lights directly beneath it and this seems to me the only precaution but
again, new guy!!!  I do have a great little stud finder that senses metal as in screws and nails but the entire roof appears to be metallic.
Is that what it comes down to if you want to hit wood? 
1996 Lance Squire 3000 if that helps..  Do they build 13" on center like houses or ???
« Last Edit: June 13, 2016, 03:18:56 PM by DesertMax »

keith c

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  • Posts: 96
Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #7 on: June 13, 2016, 03:38:25 PM »
Call the manufacturer for the schematic of the roof.  I called Jayco for my trailer and they e-mailed me the schematic which shows where speakers, duct system, etc are located.  You shouldn't hit any wiring if you use short stainless lag screws.  For example, my roof consists of 3/8" plywood.  I am going with 1" stainless lag screws, which shouldn't hit any electrical wiring since they should be closer to the ceiling than the roof.
Keith C
2017 Ford F150 3.5L Ecoboost w/ Max Trailer Tow
2013 Jayco Eagle 304BHS
320 Watts of Solar
Michigan

Gizmo

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Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #8 on: June 13, 2016, 04:14:02 PM »
It is highly un-likely you will hit any electrical wires securing the panel to the roof, unless you are using ridiculously long screws, because any electrical wiring running in the roof structure tends to be down low.
Regards, Bruce, Lin An, Kenji & Suki
2017 Eagle Cap 1165 Truck Camper With Tork Lift Fast Gun Tie Downs & T.L. Wobble Stoppers
2015 Ram Big Horn 3500 CC Cummins TD Dually 3:73 Gears & AISIN Tranny
Gone But not forgotten:
2014 Northwoods Snow River 246RKS &
2013 Aliner Expedition

DesertMax

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  • Posts: 74
Re: Adding a Third Solar Panel: Parallel or Series?
« Reply #9 on: June 13, 2016, 07:05:37 PM »
Ok sounds good..  I'll be sure to use the shallow screws then..  thanks a bunch for the responses..

 

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