How to mount solar panel(s) on the roof

... also installed aluminum uni-strut for 4ea 100W solar panels I will be adding soon,

You're using "aluminum uni-strut?" to mount the solar panels?

I'm going to ask PHX to install my one 100 watt solar panel: https://www.amazon.com/gp/product/B00L6LZRXM
using these plastic mounts: https://www.amazon.com/gp/product/B01MQF8BL1
but I also have these metal brackets: https://www.amazon.com/gp/product/B00LDHFD7O
I was thinking that it would be better to use plastic that has some give to avoid breaking the solar panel with flex stress.

I want to reserve enough space to add to 2-3 more panels someday if possible.

Are the uni-struts preferred as mounts?

There are Aluminum Channels every 2' across the roof. The easiest way to find them is to await until you have a humid morning, get up on roof with a marker and you will easily see where they are by the dew. Mark them. The only place that is practical to place the solar arrays is far forward. Remember even a small shadow will totally stop the array from generating any power.
You can mount an aluminum angle with self drilling 1/4" screws at each end of the panel.


Then remove screw and fill the hole with Dicor roof sealant, insert screw tighten and cover the nut with sealant. I have never had a screw leak on three RV's with multiple panels. Attached the panels to these aluminum angles. See picture of my roof below.

As an alternative to dewy morning roof crawling, might I suggest a cheap small metal detector?

https://www.harborfreight.com/metal-detector-97245.html   




$15, pinpoints where anything metal might be... aluminum or steel studs in a wall... stuff lost in the grass...  I got it for final target location when beach metal detecting, use it more often than I thought. 

Thanks. Doug from Phoenix USA is installing my solar panels and they certainly know where the roof struts are.

I asked how many panels he thought there was room for. He said three. I figured as long as it was being done I'd send two more panels and a 30 AMP controller.

This is moderate overkill since my mission is mainly keeping the batteries topped off since the PC is stored away from line power.  As I mentioned the house batteries died when I left them connected during storage.  My Clarion and some of my cars always need to be jumped when I visit.

I'm reminding myself that I should get a solar BatteryMinder, too.

--Mike

Properly installed more solar panels are better than fewer.  Even if the weak link is battery capacity, wire size, or controller capacity.  If you make sure your solar controller limits the max power to a level that is within the design capacity of the controller.  Yes your panels may put out more power than the system can handle under ideal solar conditions.  It is during low angle sun of the shoulder or winter seasons and/or morning/evening periods, partial shade, higher latitudes, or others factors that having extra panels is so nice to have. 


Panel power output rating is under optimum conditions that unfortunately seldom occurs in the real world.  While you are procuring and installing panels the incremental cost of an extra panel or so is usually affordable.  The pleasure of having fully charged batteries and being able to power all your gadgets during poor weather will more than makeup for the added upfront cost.  Having adequate power without the need to run that noisy generator is another unquantifiable added pleasure when boondocking.

How do you "... power all your gadgets during poor weather.." via solar?

At least to me, "poor weather" means rainy, snowy, foggy, misty or a solid overcast.

Donc13,
Our winter camping excursions usually means camping in the southland where snow is not an issue.  During overcast boondocking days we usually pickup some solar power.  I will not say we never use the generator but I do not like the noise.  I expect my neighbors dislike me running the generator more than I do so we try to minimize usage.


The point i clumsily wanted to make is having more solar panels than an “optimized” design allows for storage of more power during non optimum solar irradiation conditions.  As an example assume an optimized design called for a 200 watt panel.  During an overcast day it may output only 25% (more or less) of its optimum capacity or 50 watts.  If one had installed four panels of the same size the combined output would be 200 watts or back to original design load.  During bright sunny days the solar controller would limit the output of the panels.  A bit of a waste of power but a fair exchange if it eliminates or minimizes generator run time during non optimum conditions.


On our 2552 PC I had the factory mount two 160 watt panels behind the AC.  I had them install larger 4 gauge wiring from the roof to the controller so I could add two more 160 watt panels ahead of the AC should our needs change in the future.  With our unique needs and system we seldom use the generator.  Most days we are back to full state of charge by 10:00 to 11:00 am.

I considered solar panels a few times.  The reason why I keep ruling them out is for a few basic reasons.

1) We seek shaded camp sites
2) The added technical complexity
3) The added investment
4) More holes in the roof (I have "a thing" about adding more holes in the roof)

Maybe one day I will invest in solar panels on the roof, but I am not there yet.  I have seen solar panels on a stand, but that rules out only #1 and #4.

We resort to running the generator.  We already have it and it meets the need.

I would surely get solar on a stand if we primarily boondocked in desert regions where we would setup and stay put for a time.  I could justify that.