Let me start off by explaining that Mom has always referred to Dad as Tim the Tool Man. Like Tim Allen's character on Home Improvement, Dad believes wholeheartedly in the adage "bigger is better". (For example, she once asked him to built a 3-foot Frosty the Snowman made of wood. What she got was a 9-foot Bumble The Abominable Snowmonster!) So when it was time to design a solar system for our new rig, Mom and I were worried. The cheese wheels of Dad's brain were churning, as evidenced by the smoke billowing from his shiny bald head! Did we unleash a Monster who could not be controlled? I'm happy to say that we were able to keep Frankenstein reigned in and that our system is everything we wanted it to be.
Mom kept Dad leashed so that he didn't create a system this large. Ironically, though, this looks a little like my head, doesn't it?
But since my little stuffed rat brain can't wrap itself around explaining and discussing technology this complex, I'm going to let Dad tell you about his solar project personally while I go munch on some Cheese Nips. Over to you, Dad...
Thanks, Rambling RV Rat. Let me start by saying that my biggest obstacle initially was working without a physical specimen (We went to several dealers to actually see a 40KSSB4, but most did not have any on their lot). I could not take measurements of the roof and the obstructions up there, nor take into consideration the basement configuration where all the major components would be situated. So I was forced to make a lot of presumptions early on.
From late September 2018 (when we took the DRV tour and decided they would be the manufacturer of our next rig) up to when I was able to examine our new fifth wheel at Bennett's Camping Center during pre-delivery inspection (PDI), I was sort of working blind. I had several design layouts configured just in case one or another did not work out. To assist with what technologies were available and would work best with what we wanted to achieve….TOTAL FREEDOM FROM THE GRID…I contacted James Hall at Northern Arizona Wind and Solar (NAWS). I worked with NAWS several times over the last 14 years and was pleased with their products and services.
NAWS has been designing and installing solar systems since 1979, so they have the experience and knowledge to provide the answers I was looking for. When I contacted James initially, I explained what I wanted to do and how I wanted the system to perform.
So over the next 12 months James and I exchanged ideas, concepts, and estimates. I was diligent in doing my homework on the manufacturers and components available on the market. Regardless of what James or anyone else would advise, I wanted to make sure I was comfortable with what we were going to purchase and use. This was not going to be an inexpensive system, so it is an investment that needs to be right the first time. Each of the manufacturers and components I used I have provided links for reference.
WHAT DOES THE SYSTEM NEED TO DO
The first order of business was figuring out exactly what we wanted the system to do for us. Do we just want to be able to use a few choice appliances on occasion? What appliances would be used only on shore power (connected to the grid)? Do we want the ability to run our air conditioners on solar? Can it be done effectively? Can we get enough solar panels on the roof and enough batteries to handle such a task?
During the design phase, my wife and I discussed that if we were going to live off the grid, we did not want to be limited to using only a select few appliances at certain times or days. We knew we had generators as back up, but wanted to spend as much time enjoying living off the grid and out of RV parks without having to worry about firing up the generators every couple of days. Our previous solar system did not have the ability to run the air conditioners. And although we were comfortable living off grid, there were still the days when we had to run the generators to catch up the batteries because there was not enough sun to charge them back up. That was one disadvantage I saw with having lead acid batteries, even the AGMs we had in the Montanas (I will discuss this further later on).
So with decisions made as to how we wanted the system to perform, I now turned to my discussions with NAWS. I expressed to James the ability to be able to stay off the grid completely with minimal generator use yet still be able to use everything on board. That meant the air conditioners, residential refrigerator, convection microwave (my wife cooks regularly), fireplace including heat, television and entertainment system, kitchen gadgets (we just bought an air fryer), and the list goes on. Can this be done? Have the systems and technologies advanced enough to allow this to be possible in an RV? After talking it through with James and advancing my own research, I knew it was possible but that you had to have the right components configured properly to make it happen.
One thing we did need to do in order to run the air conditioners efficiently and to not put a huge initial load on the system when we turned them on was to install soft starts on each unit. We purchased these from Micro-Air, and they were pretty easy to install. The soft starts slowly bring the compressors online, thus preventing a big amperage draw on the system.
The Micro-Air Easy Start being installed on the ACs.
THE SYSTEM DESIGN
This brings us to what components and what manufacturers to use. If one types into Google or any other search engine “solar panel systems” you will be pretty much overwhelmed with the amount of information that will come up. Who uses this battery? Who has this inverter? What does this charge controller do? You will get everything from soup to nuts with huge cost fluctuations.
Designing a solar energy system to have the most advanced technology does not mean you have to spend a king’s ransom to get it, you just have to be knowledgeable as to who and what will work for you!
After each discussion with James at NAWS, I would get online and investigate the various components he recommended/proposed. I am going to list the components and how I determined what to use based on all the information I gathered. As Rambling RV Rat's Mom always says, there is no one size fits all in this lifestyle. Everyone's needs, tolerances, and budgets are different. But here is what met our lifestyle requirements.
On our previous Montana fifth wheels, we had a total of 1200 watts of solar panels on the roof that were able to be tilted. But my wife stated emphatically that we were NOT climbing the roof to tilt the panels on this new system. I must admit it was inconvenient for how many times we would be stationary enough to spend the time to perform that task. Another reason to not tilt the panels is that the amount of additional efficiency you pick up from tilting is only about 20%. Coupled with the fact that you only will attain peak charging efficiency for about 4 or 5 hours a day, you are better off adding another panel or two to pick up that loss.
As most of you know when you look at an RV roof there is not much room to effectively place a large number of solar panels. Yes, you can place them along the edges and in between the air conditioners, vents, antennas, etc. One big problem with most system designs is when placing the panels they tend to be close to one of the aforementioned items on the roof, and therefore at some point in the day will be subject to shading from them. This may not seem like a big deal, but it is. Shading on a particular solar panel effectively shuts it off from charging. It does not take much; only a couple of inches of shading will greatly reduce the panel's ability to send energy to the batteries. This is a very costly mistake a lot of designs have built into them, basically rendering that $200-$350 panel useless.
With the ability to run air conditioners and no tilting involved, the challenge was going to be how many panels, how big and where are we putting them. Because we would have a high residential type electrical draw we would need to achieve, I would have to look at high wattage and voltage type solar panels. This would also be important so that the batteries would also get a lot of energy throughout the day to charge them back up quickly and efficiently, even with less than ideal conditions. During the research I looked at various manufacturers, both made here in the US and abroad. Now those who know me personally know that I make every effort to buy American. While there are numerous US-based solar companies, many are just start ups who may be buying overseas components and assembling them here. How can they offer effective warranties for the same? I say effective in the sense that many of the manufacturers offer 25 year warranties on solar panels but have only been around a few years. Will they be around in 25 years? 15 years? 10 years? I was looking for a company that has been performing in this market that can offer a warranty that is backed by a third party. This way if there were an issue and that company no longer existed in its present form I could have some recourse.
After discussing with James at NAWS, I agreed with his recommendation and decided to go with REC N-Peak Solar Panels. REC is out of Norway and has been producing solar panels and components since 1996. REC is considered one of the leading manufacturers of panels in the world. I selected the REC N-Peak 320. They have a peak power of 320 watts, a rated voltage of 32.2 volts with a rated current of 9.37 amps.
After deciding on which panels, I now had to decide the where and how many. Knowing we needed to have a lot of watts to produce a lot of energy to run our new coach, I landed on 10 panels. So that would give 3200 watts of energy on the roof. I would run two 5-panel configurations in series. This would give 161 volts at 9.37 amps on each array coming down to the charge controllers. Running in series will also allow me to keep our wiring leads from the panels at 10 AWG because we are running more volts than amps through them. If I ran all the panels in a parallel configuration, I would have more amps than volts and would need to increase the wire size to at least 8 AWG from the panels to a combiner box and then at least 4 AWG from the combiner box to the charge controllers (I will discuss these components shortly).
Now that the number of panels was determined, how am I installing them on the RV roof? Well why not go right up the middle, above the air conditioners? Since the top of the air conditioners are at 13’4” above the ground, I would have to be almost right on top of them to keep below the 13’6” maximum height allowed on the interstates and major transportation roads.
To achieve this I designed an elaborate aluminum framing system to support the panels. This consisted of a combination of aluminum tubing and angles constructed in ladder frames that I could bring up to the roof pre-assembled and deploy into their configuration once up there. Here is one of the sketches I made to guide me during fabrication Roof Framing Schematic. Whenever we are on our leased lot in Livingston, we like to use local vendors as much as possible when shopping for any item, and this was no exception. I found a great economical source for the aluminum in Metal Supermarkets in Houston, TX, and I purchased all fasteners from Fastenal in Cleveland, TX. Using vendors such as these is more practical and economical for the larger purchases then using a Home Depot or Lowes.
The anchors for the framing are held in place on the roof with 3/8” stainless steel lag bolts into the ½” plywood roof. In all, there are 44 anchor bolts at 22 anchor locations. All of the bolts, etc. on the framing are stainless steel.
The combined load spread over the roof at 22 points is approximately 550 pounds or 25 pounds per anchor point.
Everything is sealed with Dicor self-leveling sealant, which you can never use too much of!
My Outside Office
Solar Combiner Boxes, Charge Controllers and Bussbars
Now that the solar panels are in place on the roof they need to bring that energy down to supply the batteries and inverters. Thankfully there was a tank vent located close with good access to the basement to be able to snake the wiring from the panels.
Cable Pulling Wire Alongside the Vent Tube
10 AWG Lead Cables Fed Next to Vent Tube to Basement
Vent Cap Re-Installed and Sealed with Dicor
Once this was done and sealed up, each wire had to be pulled to the front basement where all the main components of the system would be housed.
In order to support all of the major components of the system, I had to build two 3/4" plywood walls in the basement. We ordered the RV without any compartments in the basement (such as a generator box) so that I would be able to lay out the components in the most efficient method. The plywood was painted before the components were installed.
Because there are two panel arrays I needed to setup two solar combiner boxes where the wiring would enter. The positive leads would first connect to a 15 amp breaker then to the charge controller. The negative lead would go directly to the negative side of the controller for the panel inputs.
The boxes, called Baby Boxes, are made by Midnite Solar, and they provide both an input and an output breaker, thus eliminating a need to have separate disconnects between the boxes and the controllers.
The charge controllers (CCs) are made by Victron Energy. I chose the Smartsolar charge controllers in a 250 volt/70 amp configuration as I would be bringing more volts than amps in them by wiring the panels in a series configuration. These are maximum power point tracking (MPPT) controllers, which means they are constantly looking for the highest energy point and will harvest this point to send to the batteries. These controllers are also Bluetooth smart so you can monitor from your smartphone and also link directly to the Victron Color Control GX monitor (more about that later).
Once the solar energy is supplied by the panels to the CCs they then send it into the batteries. They are wired back into the baby boxes with the positive lead passing through an 80 amp breaker to the bussbar and the negative passing straight through to the bussbar.
Because of the sophistication of the system and after consulting with NAWS, I opted to use Victron's Lynx Power Distribution System. It is very clean and easily expandable. For our system I needed a Power In load center where all the batteries tie into, a Lynx Shunt where all of the data is transmitted to the operating monitors and which also provides a catastrophic fuse in case anything was to go awry between the batteries and the main distribution bar. The final piece is the Lynx Distribution Bar, which is where the leads from the controllers connect, where the main leads for the DC systems will exit to provide the 12-volt power the RV needs, and also where the main leads will exit and connect to the two inverters. Each lead on the Distribution Bar is also fuse protected. That is the beauty of the Victron system as there is a lot of safety redundancy.
All the Components Located in the Front Basement
Ready to Build Some Cables!
Using a 16 Ton Crimper is the Only Way to Make Good Connections to the Lugs
Each End is Protected with Heat Shrink Tape
Each Wire/Cable Run is Carefully Planned and Routed
All Cables Runs for Each Battery/Charge Controller/Inverter, etc. are the Same Length to Keep Resistance in Each Cable the Same for Each Component
The Finished Basement Compartment
I opted for Victron Multiplus 24/3000/70 Inverters. I used two of them in parallel which will provide 6000 watts at 50 amps to run everything in the RV including both air conditioners at once if we need or so choose. These inverters at 24 volt can each push 70 amps of charging into the batteries if necessary. They are fully programmable to pretty much any configuration you need, but for our system I have them configured to our 24 volt batteries.
They are each protected by a 200 amp breaker coming in from the batteries. They are also Bluetooth connected via the Victron V.E. Direct dongle.
The Parallel Inverters
In order to run them in parallel from both the shore and boondocking side, I opted to install an AC combiner box which can bring either shore power or battery power and distribute it to the main electric panel of the RV. There are other ways to achieve putting the inverters in parallel; but after discussing with NAWS, this was deemed the most practical and cleanest method.
Since all of the circuits of the RV I wanted to run are on the boondocking side, I only needed to run one side of the 50 amp service coming in from the shore power through to the AC combiner box. The other side of the 50 amp service stops at the 50 amp double pole breaker. If in the future I decide I need to extend that to a subpanel, it can be done easily. But for now I do not think we need 12000 watts from the shore.
Ah, the Fun of Pulling Wires for the Disconnect, Main Panel and Monitor!
The New Disconnect and Main Breaker Panel
In the combiner box there are four bussbars, incoming AC, outgoing AC, Neutral and Ground. This provides a simple and clean solution to running the power leads.
Once the AC power is brought to the bussbar it is then split to both inverters. Because the inverters each have a 50 amp transfer switch built in there was no need for an exterior transfer switch or subpanel. The AC output from the inverters then goes to one bussbar which then supplies a lead to the main panel for all AC loads in the RV. All of the AC input and output share common neutrals and grounds.
AC Combiner Box
We also installed a Progressive Emergency Management System (EMS) hardwired before the 50 amp disconnect which monitors and protects the RV when hooked up to shore power. This is located in the basement under the cabinet where the disconnect and main panel are located. The EMS will protect our RV from surges, bad pedestal wiring, etc. should we opt to connect to shore power.
During the design phase of the system, I had a lot of discussions with James at NAWS about what batteries to use, how many and who the various manufacturers were and what they offered.
I knew definitely that I would be going with Lithium based on what our overall power needs would be, but was uncertain of size, how many amps and at what voltage.
Because of the size of the panel array, 24 volts would be the most practical and energy efficient solution. It allowed for decreased wire sizes (more volts less amps equals smaller diameter wires). It is a function of Ohm’s Law of resistance. Using the formula Volts (V) x Amps (A) = Watts (W), take 24V x 50A = 1200W, to get the same watts at 12V x 100A = 1200W.
What this basically says is at 24 volts you are pushing less current A through the wire allowing you to use a smaller wire which has less resistance. In simple terms you can use a smaller pipe to bring the water to the source because the water pressure is less going through the pipe.
There are several good manufacturers in the market who could have provided what I needed. But in the end I chose Simpliphi PHI 3.8 kWh 24 volt Lithium Ferro Phosphate. Simpliphi Battery provided the best options and the biggest bang for the investment: a built in battery management system (BMS), a built in 80 amp DC breaker on/off switch, a 10-year warranty (from a company that has been around since 2000) 10,000 cycles at 80% depth of discharge (DOD)…..and these batteries are truly MADE IN THE USA! All components are designed, engineered, manufactured and assemble here! Additionally, Simpliphi has been a large Dept. of Defense contractor helping protect our troops overseas with their innovative solutions.
I used four of the Simpliphi batteries giving us 15.2 kWh, 604 amp hours at 24 volts. These four batteries weigh in at 312 lbs., about half of what a similar setup using lead acid batteries would weigh. More importantly, every single amp hour is usable on the lithium (where only 50% are usable on acid batteries), and lithium batteries charge considerably faster than acid batteries.
Having a 24 volt system also means I have to use a DC to DC converter to step down the 24 volts to 12 volts for all of the typical RV house loads such as the lights, etc. Most importantly, the Lippert hydraulic system which runs the level up jacks and slide outs runs on 12 volts and uses high amps. I chose to use the Victron Orion 24V/12V 70 amp converter for that particular reason. I wired the converter directly into where the original house 6 volt battery connections were thus avoiding a lot of rewiring of the 12 volt system.
So now that I have this high-end. sophisticated solar charging/energy system, I need to be able to monitor it to ensure it is operating properly, to know our energy consumption, and to know how much energy it is producing.
I chose to use Victron Color Control GX which is both Bluetooth and WiFi capable thus allowing on-the-fly monitoring and control.
The Main Control Center with the GX in the Upper Right
A Snap Shot of the Color Control GX in Action while using one of the Air Conditioners
The GX connects directly to the Lynx Shunt and reports how much solar comes in, how much of that solar is going into the batteries, how much is consumed by the RV, where the battery state of charge stands, and how much DC and AC loads are being used.
The monitor will allow us to check and change the system parameters from anywhere as long as it has an internet connection and the use of the Victron VRM app on our smartphones.
The Completed System
From start to finish it took 17 days and 75 hours to layout, build and install all of the components. This includes installing walls in the basement to support the major components, building the rack system for the roof and constructing all of the wires and cables. All cables are hydraulic crimped and heat shrinked. All of the miscellaneous wire and cable runs are covered with split loom to protect them.
I put the system on line October 24. We went completely off the grid October 31. Since then we have been running the air conditioners when necessary. We use all of the appliances regularly including the convection microwave and air fryer. We watch TV, have the residential frig running, and have used the furnace since we have had an arctic blast land on us here in Texas.
We are trying to push the system limits each day to see if there are any issues. We have not had to run the generators or reconnect to the grid in nearly a month. The lowest the batteries have been drawn down to is 50% by just going about our daily lives. We have had both bright sunny days and multiple cloudy rainy days where there was limited sun and yet the panels still charged the batteries fully on those days.
We are very happy with how the system is performing to date. I want to give a very big thank you to James at NAWS for his patience and the expertise that he provided during the design and implementation process.
Thanks for making my head spin, Dad! Well, there you have it folks. The scoop, poop, and gobblygoop of our solar system. We are ready to enjoy boondocking in Quartzsite in January!
I'll talk to you again soon! Hope you all have a Happy Thanksgiving!
We would like to thank the following organizations for all the great service and support they offer to the RVing community:
3200 watts!?!?! That is quite the system. Great job on the research and installation!ReplyDelete
Very impressive looking system Les! So neatly laid out. Not only a lot of work on the install but writing about it too.ReplyDelete
How much weight did this add?ReplyDelete
The entire system with all components and materials added approximately 1000 lbs. to the RVDelete
How close does that make you to the GVWR of the 5er?Delete
Well Mr Rat ==== busy busy busy!ReplyDelete
Wondering if the "basement" has crawl space??
Good Read -- just hope there's not a pop quiz
Safe Travels My Friends ---
Great write up and pics. Why two charge controllers. Why not one large one?ReplyDelete
We used 2 controllers because running the two sets of 5 panels in series was going to bring over 160 volts into the controllers. Presently there are only CC's up to 250 volts on the market so to try and bring all the voltage into one CC would be over 320 volts.Delete
Running the 2 sets of 5 panels in series allowed more efficient wire runs with less power loss, more control of the panels by having 2 combiner boxes with the ability to turn either or both on or off should service or an issue arise.
If we ran all the panels in parallel the wiring gauge would have had to be greatly increased due to the amps being brought down from the roof and we would have had to have a roof top combiner to run all the panel cabling to be able to run at the heavier gauge wiring down to the combiner.
Why not combine the two sets of 5 in-series panels, for more current into one controller?Delete
That is a great system!ReplyDelete
That seems to be like a big wing; I'd be concerned about wind under the solar panel array and creating a lot of lift and stress. Do you have an air dam to block wind? Or other thoughts on this? Thanks!
As designed there is an air foil installed on the front of the rack to divert air up and over the panels. Thanks for your thoughts.Delete