What can you tell me about our Solar system?

[jymbee]

I'm afraid that other than the brief view I had of our rooftop solar panels during a pre-purchase inspection, I know very little about how the system actually works. The sun shines, the panels produce electricity, the electricity is stored in... uh... the coach batteries. How am I doing so far?? 

During a recent ferry crossing I got a chance to get up close and personal without climbing up on the roof using the built in ladder (something I plan on never doing btw). Took advantage of the that opportunity to snap some images. Hoping to learn a bit more about how it all works and what kind of benefit to expect from it:

http://byz.com/rvsolar/solar_1.jpg
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http://byz.com/rvsolar/solar_2.jpg
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http://byz.com/rvsolar/solar_3.jpg
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http://byz.com/rvsolar/solar_4.jpg

 

[grashley]

Our Solar system is part of the Milky Way.  Our sun has 8 planets rotating around it.  Used to have 9, but Pluto got demoted.

What else do you want to know? 

 

[jymbee]

Our Solar system is part of the Milky Way.  Our sun has 8 planets rotating around it.  Used to have 9, but Pluto got demoted.

What else do you want to know? 

Excellent!!  ) )

 

[PJ Stough]

What I can see is that you have three panels connected in parallel, and the it appears that the wire is undersized.  Not sure of the watts of the panels, maybe ~150?  Do you have any pics of the solar controller?

 

[IBTripping]

Our Solar system is part of the Milky Way.  Our sun has 8 planets rotating around it.  Used to have 9, but Pluto got demoted.

What else do you want to know? 

And let me guess. Your favorite planet is Uranus.  ;D : ;D

 

[Kevin Means]

Yeah I was thinking the wires looked a little on the thin side too, but it's hard to say for sure. Looks like a pretty generic solar setup. With the possible exception of that forward vent when the sun is low on the passenger side, I don't see any shading problems. It looks like the panels may have manual tilt kits, which makes a big difference in panel output during winter months. Depending on your consumption, AH capacity and the total output of your panels/controller, it could be a useful setup.

Kev

 

[AStravelers]

During a recent ferry crossing I got a chance to get up close and personal without climbing up on the roof using the built in ladder (something I plan on never doing btw).

Solar panels get very dirty and must be cleaned every few weeks to every couple of months or even more frequently if there are dusty conditions.  Otherwise you loose a lot of power output from the panels.  Not going up on the roof presents a real problem. 

You probably have from 300 to 450 watts of solar power.  The possible small wire size may reduce the amount of power getting to the solar controller and batteries.  Shading of the solar panels is possible from the two air conditioners.  Shading just a small part of a solar panel kills about 90-95% of the output from that panel. 

Below are two links with some detailed info about solar, batteries, charging, power consumption, etc.  Read though the info and try to relate the info to your batteries, solar panels, inverter, solar controller, etc.

Come back with specific questions about what you find that isn't clear to you and many folks where will be glad to provide good info and clarification.

http://www.marxrv.com/12volt/12volt.htm
http://www.marxrv.com/12volt/12volta.htm

 

[Memtb]

  The wires from each panel do look a little small, but may be adequate depending upon the panel wattage and length of wiring run to the junction box. From what I see, the size of the wiring from the junction box to the charge controller would be my biggest concern!  That would require observing the wire size at the charge controller!  Although, where the wiring goes under the vent cover, it also looks a bit light gauge. Try and determine solar panel total wattage, wire gauge to the controller, and length of wire run to the controller.

    Solar panel systems while darn nice, are very sensitive to various issues, clean panels, wiring size (smaller wires equal greater wattage loss), good clean connections, and unobstructed, proper angle of panels toward the sun.  Solar panels, when everything is right, are a nice asset....but are pretty limited in overall performance. That said, we’ve been using them since the mid-‘90’s, and wouldn’t be without them. You just have to understand and respect their limitations!

 

[Gary RV_Wizard]

I know very little about how the system actually works. The sun shines, the panels produce electricity, the electricity is stored in... uh... the coach batteries. How am I doing so far??

E3xcellent!  Remember that the battery bank is as important as the panels - solar power generation is almost zero usefulness unless you can store all that power.

The three bigger panels & controller are clearly an add-on system - only the little one on the a/c cover appears to be factory original. It probably trickle charges the chassis battery.

 

[jymbee]

E3xcellent!  Remember that the battery bank is as important as the panels - solar power generation is almost zero usefulness unless you can store all that power.

The three bigger panels & controller are clearly an add-on system - only the little one on the a/c cover appears to be factory original. It probably trickle charges the chassis battery.

Great info from all of the responses-- thanks to all! I'm slowly learning...

Yeah, these were installed by a previous owner. The small unit on the AC cover as you pointed out must indeed be a factory install.

As for the comments re. wire size, how can I determine the size of the wires in place currently and how much of a project would it be to replace/upgrade them it there would be a discernible benefit?

Also good advice re. positioning with respect to other objects up there as well as keeping everything clean. There's tons of pollen from the trees where we're camping now and I would expect to see an accumulation on the panels.

Here's a pic of the controller. Seems whenever I think to check it this reads the same 13.5 V. (?)

http://byz.com/rvsolar/system_1.jpg

 

[AStravelers]

Great info from all of the responses-- thanks to all! I'm slowly learning...

Yeah, these were installed by a previous owner. The small unit on the AC cover as you pointed out must indeed be a factory install.

As for the comments re. wire size, how can I determine the size of the wires in place currently and how much of a project would it be to replace/upgrade them it there would be a discernible benefit?

Also good advice re. positioning with respect to other objects up there as well as keeping everything clean. There's tons of pollen from the trees where we're camping now and I would expect to see an accumulation on the panels.

Here's a pic of the controller. Seems whenever I think to check it this reads the same 13.5 V. (?)

http://byz.com/rvsolar/system_1.jpg

About the wire size......Look closely at the individual wires for a number like "10 AWG" or "10 GA" or "#10" printed along the length of the wire. The number most likely will be from 14 to 10.  It will be in string of names, numbers and other info.  BTW #14 wire is smaller than #10

If the RV is plugged into shore power the 13.5V is most likely the "float" voltage from the charger in the RV.  The charger could called a "converter" or is part of an inverter/charger.  If you have an inverter, let us know the name and model #. 
If the RV is not plugged into shore power the 13.5V is the float voltage from the charge controller.

 

[Gizmo]

What I can see is that you have three panels connected in parallel, and the it appears that the wire is undersized.  Not sure of the watts of the panels, maybe ~150?  Do you have any pics of the solar controller?

My thought as well and I would add it looks like you may run into some shading issues which will reduce solar output if you are parked with the front and rear of your rig on an east west axis.

 

[Drewd]

At least 300 may 450 watts total.

IF wired in series, the wiring from the combiner box to the solar controller should be adequate with acceptable voltage loss.  all wire loses voltage over a run.  The thinner the wire and the greater the run, the greater the voltage loss which is wasteful for something that costs so much to install.  Increasing voltage thru the selected wiring by running panels in series increases the voltage which minimizes voltage losses.  Not sure how yours is wired.  Series versus parallel panel wiring is something you can google.  There are advantages and disadvantages of both.  My system uses two panels wired in series and then groups of 3 of the two in series wired in parallel to minimize disadvantages of each wiring scheme.

Series panel wiring  (higher voltages to solar controller) requires a MPPT controller which results in higher efficiency (more power to batteries) than a cheaper PWM system. 

For every 100 watts of solar, I prefer to have a minimum of 100 amp/hours of battery capacity.

Lots of solar info on the interweb.  Handybob solar is a good reference but some of his information is a little inaccurate.  I'm not a believer for spending 100% more on controllers or inverters when I can get 90% of the efficiency, capacity (battery), or reliability for 50% less.  The extra savings go towards more batteries and panels for me.  For example, I paid $100 for renogy 100 watt solar panels that were about 19,8% efficient and didn't see value in spending $200-$225 for panels that were 21% efficient.  The panel efficiency does add up for applications where you have dozens of panes but typically not for RV.s

A highly efficient setup with the best controller and panels is worthless if the wiring is undersized.  I do solar installs each summer and often fix ones that were done by "professional installers" that didn't work as well as expected because 10 gauge wire was used to run power from the combining box on the roof to the solar controller 30 feet away resulting in 1.5 volt drop. 

Show us more pics of the controller and whether you have an inverter, pics of battery bank(s) good too.

 

[Drewd]

A shunt and a Trimetric or Victron monitor will really tell you how much current is being produced and pushed into your batteries while charging.  Will also give you an idea of ho w much power you are using throughout a typical day to inform you if you need more panels and/or battery capacity so you do not go below recommended state of charge on lead acid or AGM batteries.

 

[djw2112]

Our Solar system is part of the Milky Way.  Our sun has 8 planets rotating around it.  Used to have 9, but Pluto got demoted.

What else do you want to know? 

When i read the title i was going to reply with similar... tooooo funny