Hi Guys, I've been getting a lot of help from the knowledgeable staff and members here at RV net and wanted in this post to focus on one thing only and that is the solar charger itself: that all important sun getter on the roof!For me, quality has been of highest concern with everything I do in my technical life. I have never bought cheap and have often watched a family member replace an item over & over because they loved the "deal" they got. Buying price instead of quality can bite you in the bum!I researched the difference in mono to poly panels and mono seems to have the specs and of course with that comes the higher price. Now it appears that price could be getting lower for what appears to be the same good quality. My first TC had a Siemens SM55 Panel and I appreciated the quality and the results it produced.My new rig has 2 of these and while I have yet to flip them over to gather exact data from the backs of the panels, I am confident they are in the 50W area just like mine..So the question that I have now is this: Is one 150W panel of high quality really "better" than 3 50W panels of equal individual quality?Where "cheap" and "quality" meet???

Exterior terminations are always a weak point that should be factored.

HiEach connection you make increases the risk of failure. There may also be more roof penetrations with multiple panels.If I had my choice, I would go with a single 150 watt instead of three 50 watt units. I would choose poly over mono from what has been reported here.btw that is not a particularly good price.DesertMax wrote:So the question that I have now is this: Is one 150W panel of high quality really "better" than 3 50W panels of equal individual quality?

Two thoughts:One 150 watt panel has less wiring single mount, three has more wiring and more mounting work. One 150 watt panel with some shade = 0 watts, Three 50 watt panels with some shade = 100 watts.You chooses your poison,Doug

doughere wrote:Two thoughts:One 150 watt panel has less wiring single mount, three has more wiring and more mounting work. One 150 watt panel with some shade = 0 watts, Three 50 watt panels with some shade = 100 watts.You chooses your poison,DougTrue, but two 150 watt panels (on opposite sides of the trailer) with some shade = 150 watts. And an intermediate among of wiring and mounting.

Solar Panels - The Good, the Bad and the Cheap!

40 Replies

DesertMax
Explorer
May 30, 2016
I love solar!
DesertMax
Explorer
May 30, 2016
Thanks guys... old, that's an article I've been looking for although there seems to be some controversy over

"Maximum voltage on a string of modules must always be lower than maximum input DC voltage of the inverter."
pianotuna
Nomad III
May 30, 2016
Home systems often have grid tied inverters. I think this where folks are getting confused. If they had said grid tied then all would have been well.

Almot wrote:
"Inverter" must be a typo, it has nothing to do with panels wiring. OTH with "controller" the sentence would make sense.
Almot
Explorer III
May 30, 2016
DesertMax wrote:

why perhaps you wouldn't have 2 seperate systems.. so could I just keep the system I have after adding the 3rd 50W panel and then build up a new one with those more square 150 watters from eby... problem is that only the main system would be house..

You don't need 2 systems on one rig.

2nd towed rig or cargo trailer should be equipped with its own system including controller and batteries, to avoid running high amps through the coupling. If you think you need another system on that towed rig.
2oldman
Explorer II
May 30, 2016
Almot wrote:
OTH with "controller" the sentence would make sense.
x2
Almot
Explorer III
May 30, 2016
"Inverter" must be a typo, it has nothing to do with panels wiring. OTH with "controller" the sentence would make sense.
2oldman
Explorer II
May 30, 2016
DesertMax wrote:
say I had my rig towing a 20 foot cargo trailer and I wanted to fill the roof with panels.
Can I just use the roof space any way I want with different sizes and shapes like a big electrical puzzle???
The link above explains about matching. Physical size is not important.
DesertMax
Explorer
May 30, 2016
The one last thing I still don't find a lot of direct answers to is just the matching?

Do I have this correct?? Batts must be matched ie: AGM batts in the same system with tire store "cranking amps" junk car batts a big no no..?

and in terms of panels? say I had my rig towing a 20 foot cargo trailer and I wanted to fill the roof with panels.
Can I just use the roof space any way I want with different sizes and shapes like a big electrical puzzle???
DesertMax
Explorer
May 30, 2016
Ok guys now see I did not know that.. products in the industry HAVE changed haven't they.. I remember poly used to be a lot less $$$ too..

I've often wondered too in a situation like mine why perhaps you wouldn't have 2 seperate systems.. so could I just keep the system I have after adding the 3rd 50W panel and then build up a new one with those more square 150 watters from eby... problem is that only the main system would be house..
2oldman
Explorer II
May 30, 2016
Almot wrote:
You might want to read This on panel wiring.
Pretty good read.. and mostly correct for a home/rv installation.

Saw this:
"Maximum voltage on a string of modules must always be lower than maximum input DC voltage of the inverter."

I guess homes don't use a controller..? or is that a misprint?

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Solar Panels - The Good, the Bad and the Cheap!

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