Friday, October 9, 2015

Our Solar Power Setup

Our solar power setup is one of the most critical things to our being able to travel full-time, with no restrictions on where we park. The ability to create all the power we need (along with our own water supply) will let us park anywhere without hookups, giving us many more opportunities to stay overnight where others can't (or won't), as well as to save as much as 50% on fees in campgrounds just by allowing us to take sites in undeveloped areas or overflow areas.

We hadn't originally planned on having solar power this soon. We had it on our want list for when we got out west, or the Pacific Northwest, where there are skilled dealers and installers. But, when one of my readers saw that we had it on our list, he offered us a nearly complete setup, still brand new and unused, at a considerable 55% of what those same components would have cost if we had bought them from the original supplier.

The only things that were missing were the shunt and the battery temperature monitoring cable. The shunt is basically a high power resistor that allows a meter to detect large amounts of power and convert it to a smaller voltage reading that the meter can handle. The current flowing through the shunt produces a slight difference in voltage between the input and output side, and that is what the remote mounted meter reads. The shunt converts a potential 500 amps of capacity to an output voltage of 5 volts, full scale, if measured on an analog meter. The digital meter converts it to readable figures on the digital display on the battery monitor.

The temperature cable is not a critical item, but since the system was designed for it, we bought it anyway. It has a temperature detector built into the end of the cable that attaches directly to the battery, and allows the remote meter to measure the battery temperature and adjust the charging rate by how warm the battery is. The system would operate without it, but it just gives that extra degree of accuracy to obtaining a perfect charging rate.

So even with the extra items purchased directly from the dealer where the system came from, we're still at only 59% of actual retail value. And we didn't even use the tilt bars that came with the system.

From everything I have read about tilt bars, the ability to tilt the panels into the direct rays of the sun only increases the overall efficiency by about 20%. And that's only if you "keep" them facing the sun. That could also involve being able to rotate the panels or your RV to constantly face the sun. Otherwise, it doesn't matter if you face them directly into the sun at noon. Before 10 o'clock and after two o'clock you are already going to be at an angle that negates the whole idea of the tilt in the first place!

I am 67 years old, with a bad back. The trailer (or any other RV except for maybe a tear-drop camper) is going to be higher than I can reach without a stepladder. I AM NOT going to get a stepladder out every time we stop for a day or two, just to tilt solar panels to get 20% more efficiency from them! If I need 20% more efficiency for my needs, I'll add a third panel on the roof, and gain 33% more efficiency! Problem solved!

Now, to the rest of the story. The roof rack to hold the panels has already been discussed in a previous blog post. It shows how we added some treated wood strips to the tops of the bars, to which we can screw down the brackets using the stainless steel screws provided. This way, nothing has to be changed on the brackets themselves in order to make them work as intended.

The first thing that should be done before doing any wiring on any kind of panel is to cover the surface with a light blocking material. If it can't get light, it can't generate a charge, which could possibly give you a slight shock (not enough to hurt you). Also, you don't want to cut into any live circuit, especially on delicate components, as it could cause a short and damage the device.

I happened to have a couple large pieces of cardboard left over from something we ordered online, and I simply laid it out on the work table and set the solar panel on it, face down. Then I used a pencil to trace around the perimeter, then cut out the shape with a utility knife.

Solar panel on cardboard.
After the template was cut out, I attached the cardboard to the face of the solar panel with short strips of packaging tape about every six inches around the edges.

Solar cover template cut out.
Only after making sure the solar panel was covered did I continue to make up the connections as per the manufacturer's instructions. This requires attaching their weather proof cable to the leads on the solar panel. They provided special silicone-filled crimp connectors, and silicone-filled shrink tubing with which to cover the connections, as well as the wire ties and an anchor, the latter of which were already installed on the panel. They also supply others, which you will have to place as needed, depending on how you route your wires. 

Completed connection and shrink tube on under side of solar panel.
One tip here, is that if you don't own a professional heat gun, you will likely have better luck on the shrink tube by using a propane torch on it. I tried a 1400-watt gun type hair dryer, with a focused tip on it, and only had partial success. I ended up using a candle, because I couldn't find my torch at the time. Just be careful you don't hold the flame on any one spot too long, or you could damage the shrink tubing. You can watch it as it starts to shrink, and when it looks like it can't shrink any more, get the heat off that spot. Try to apply the heat to all sides of the tube, not just one side, and keep the heat moving to try to spread the heat as much as possible.

After the connections are made and secured at the first tie point, You will have the remainder of the cable hanging, which can get quite heavy. To install the panels, you will have to flip them right side up, and all that wire is going to get in the way, especially when trying to work over your head. The best thing you can do is coil it up and use some of the plain wire ties to secure it to the bottom of the panel, until you get it mounted in place. These panels had extra holes along the edges, and were just the right size for the wire ties to pass through.

Solar cable wire-tied to frame.
One problem I ran into with these panels is that their brackets did not fit with the ease they were supposed to. According to their instructions, all you were supposed to do was snap the brackets over the edge and bolt them in place. When I tried to do that, the brackets were so far off the edge that very little of the top part of the bracket was holding the panel! I just didn't like the way they were designed!

In the photo below, you can see how far off the holes were misaligned. I moved the bracket down a little bit to show the hole location, but even if it was slid to the right, the hole would still be about 3/8ths of an inch off!

Misaligned mounting holes!
In the photo below, you can see where the hole in the bracket actually falls in comparison to the proper position of the bracket. Structurally, this is a very poor place to put a hole, right where two pieces of metal come together without being welded together.

A bad place to put a hole!
The ideal thing would have been to design the brackets with the hole drilled farther back, so that they matched with the hole in the solar panel frame. This was a case of sloppy engineering! But...I had to deal with it as best I could. Thankfully, my machine building experience and a hefty supply of tools lets me tackle jobs that most handymen shouldn't!

For drilling in such a precarious place, where it would be hard to keep the drill bit steady, or the bracket from shifting, the minimum required is a clamp to hold everything in the proper place. The clamp has to be placed over the solid edge of the frame. If placed too far in, the metal would flex and clamping force would be lost.

Mounting bracket clamped to edge of solar panel.
In the photo above, I used one of the mounting feet under the drilling point, just to prevent damage to the solar panel. These mounting feet attach to the outer side of the mounting bracket that is currently being clamped. Once the hole was drilled through the apex of the corner of the metal frame, the supplied stainless steel hardware was installed. This had to be done on all four corners of the two panels. To reinforce the butted edges of the corners of the frame, I added large fender washers on the bottom side for extra strength. The nuts holding everything together are nylon insert lock nuts, and should never loosen on their own. These are the only kinds of nuts I use on machinery placed in moving or high vibration environments.

Mounting bracket secured in proper location with proper hardware.
The space between the bracket and solar panel is pre-spaced by an offset in the bracket, and is designed to allow clearance for the bolts which hold the mounting feet to the bracket. The tilt arms would also be mounted here, except that I didn't use the tilt arms on my installation. The mounting feet are just angled pieces with several holes in the upper leg to allow for height adjustment, and two holes in the lower leg for the stainless steel mounting screws that secure the panel assembly to the mounting our case, the roof rack.

In order to make the space for a potential third panel on the 70-1/2-inch-wide wood strips on the roof rack, I had to do some more finagling with the mounting feet. I found that if I turned the outside feet inward, and overlapped the outward facing mounting feet where the panels abut to each other, I could balance out the width on the roof, and make room for that (potential) third panel. If you look at the photo below closely, you can see the position of the brackets. (Ignore the dirt under the solar panel. It will get washed off.)

Note the orientation of the mounting feet on the solar panels.
Also, rather than use the large black knobs which are supplied to mount the feet to the panels and facilitate using the tilt arms, I decided to buy the proper size of stainless steel machine screws to use in their place. After all, this is a "permanent" installation, and nothing should ever have to be moved once it's mounted, so why do I need knobs?

After both panels were mounted, it was time to route the cables over to where the "combiner" box was to be located. Electricians simply call them junction boxes, but I guess solar installers have to be different. The "combiner" box was located directly above the edge of the right side of the inner closet wall. This was accomplished by using a long thin bit, and drilling up through the roof from inside the closet. Once the hole was located on the roof, a larger hole saw was used to drill down into the closet.

Care was taken here to not get too close to the edge of this curved roof...otherwise it would have been difficult to seal the hole under the "combiner" box. The box itself was designed with an opening through the back (in this case the bottom, as it was laying flat on it's back).

The combiner box mounted and wired.
To prevent the cable from slipping down through the hole, a strain relief was provided by using a standard 1/2-inch romex cable connector, and cutting the threaded part off with a hack saw. The clamp part was used with the screws accessible from inside the combiner box. After all cables were cut to length and inserted through the weatherproof cable connectors (supplied with the system), the combiner box was secured to the roof using stainless steel sheet metal screws, with a liberal coat of Dicor sealant under it and all around the edges, and then it was wired.

There's nothing technical about this. It's simply white to white and black to black using the two terminal strips inside the box. If we decide to add a third panel later on (only if we decide we need it), there are plenty of terminals available to add extra wiring.

Note wiring secured and the finished combiner box.
Before finishing the wiring in the combiner box, the cables under the solar panels were secured with additional self-adhesive wire-tie mounting pads. Make sure you clean the spot where the stick-on pads attach with alcohol. Some of the supplied wire-ties were the type with a screw mounting hole in the top, and these worked very well for securing the cable to the edge of the wood strips on the top of the roof rack. This cable is VERY stiff, so don't try to bend it too tight. Just let the natural curve take it where it will, and guide it to the termination point at the combiner box.

This finishes the outside work. Now for the inside work.

The cable was brought in flush with the closet wall, so it was just a matter of securing it to the wall. But before that was done, we added a battery disconnect switch in the circuit, along with a 30-amp self-resetting circuit breaker before the cable entered the charge controller.

The solar charge controller and wiring.
Several things should be noted here. First, a disconnect is not totally necessary, but if you ever have to work on the system during the day, it cuts off any incoming power from the panels. There is also a disconnect switch on the batteries, so that shutting off both switches makes the system dead, and safe to work on. Also, although it doesn't really hurt anything to have separate charging sources, such as from a converter/charger and also from the towing vehicle, it allows you to isolate these sources, whether for testing components or monitoring effectiveness.

I don't really like these "free standing" disconnect switches, but they were all that our local auto parts store had. I've seen others on Amazon that are contained within a box, that would look much more professional. All I could do in this case was secure the cable to the wall on each side of the switch. I just don't like having terminals pushed against a combustible surface like wood. If a connection becomes loose, it could create heat, and therefore is a potential fire hazard. This will get changed when I get time.

The self-resetting circuit breaker is a standard automotive item, and should be in the circuit to protect both the panels as well as the charge controller. Again, they are flunky-looking and mount to a surface, exposed, but they are what they are. The charge controller comes with its own junction box, and the solar company even provided cable connectors for it. NEVER wire something without proper connectors when going through a sheet metal hole. Vibration can eventually eat through the insulation on the wires and cause a short, especially in moving vehicles.

The other wire going out of the charge controller goes over to the corner of the closet, where eventually there will be an angled cover to conceal all the wiring, and then straight down to the batteries, mounted in a box at the bottom of the closet, and to the shunt. You can see the shunt on the left, just above the batteries. On the right is our 1500-watt modified sine wave inverter, soon to be changed out for a new Xantrex 2000-watt PURE sine wave inverter. (We found out during our recent trip, that our microwave won't run on a modified sine wave. More about that later.)

The battery compartment with the lid off, and the shunt and invterter.
Not shown yet, is the 6-terminal 12-volt fuse block that was added around the corner from the shunt. That protects all the 12-volt circuits in the trailer. The photo above shows the battery compartment with the lid off. No venting is required, as these are two six-volt, 225 amp-hour AGM batteries. Wired in series to get 12-volts output, they still only produce 225-amp hours, total. We have yet to determine whether these are better than having two 12-volt, 225-amp-hour batteries wired in parallel producing a total of 450 amp-hours, but with only half the plate capacity. More research is required.

The pipe in the left of the photo above is the drain pipe that runs from under the kitchen sink back to the portable gray water tank in the rear storage compartment. It was held out from the wall purposely to avoid having to drill through the rear stud in the closet walls and cabinet framing, as well as to allow clearance to add fittings to the ends. Under more ideal timing, I would have added this to the wall first and then notched the walls and cabinets around it, making it easier to remove or change a cabinet in the future, but I didn't have time to do that.

Next to the charge controller is the battery monitor. The curious thing about this is that the solar company supplied another junction box exactly like the one for the charge controller...but it doesn't even come close to fitting the battery monitor!

The battery monitor for the solar setup.
Again, more finagling! I had to locate some sheet metal, which I could only find in two pieces, and had to cut each one to fit around half of the battery monitor! It's not ideal, but how hard would it have been to provide a mounting box and/or adapter panel to make this monitor fit in a box properly? Not everyone is going to mount it in their living quarters on a nice fancy display. And why make the instruments such that they have to be mounted in two separate locations? Some better judgment in engineering techniques is needed here!

In our case, I mounted both boxes so that the instruments could be mounted side by the closet! I didn't see any options available on their web site for any other junction boxes or adapter plates to make the battery monitor fit the junction box for the charge controller...but some better way of doing this is needed.

Other than the problems mentioned in this post, the system seems to work well, although we have only had about three weeks to use it. I have been occasionally watching the battery monitor to see what it is doing, but I haven't really "analyzed" anything enough to provide a good report.

I have not yet installed the rest of the wiring to get the charge circuit from the van back to the trailer. That will be done before we leave here. I do have a small 15-amp AGM multi-stage battery charger hooked up when we have a shore line to plug into. The refrigerator was not running off the inverter on the way to Indiana, but we did plug it into the inverter before we made the trip back here. Since we got back home from our trip, the inverter did go into under-voltage alarm once. So we moved the refrigerator over to run off the shore power. We experienced three days of overcast weather, which undoubtedly reduced the solar output, and apparently the little 15-amp charger was not putting enough back into the batteries to keep up with usage. We may get a larger one later, or better yet, a full-blown converter charger. But once we removed the refrigerator, the system didn't take long to recover.

As far as other loads, all we have is the two LED ceiling lights, the LED patio light, and the two Fantastic fans in the ceiling. We normally run only one at a time. We have five "under cabinet" strip lights with six LEDs each running off penlight batteries, but again, we don't normally use more than one or two at a time. We have been running everything else off shore power.

The conclusion is that if we are boondocking for extended periods, and endure more cloudy skies, we could feasibly deplete our battery system after as little as three days without some additional input. If we stay connected to the van, or at least park it close enough to plug into it...we could run the van to add some charge to the batteries. The system seems to be somewhat "borderline". I think we would be fine with all sunny weather, but a few days of clouds could be a problem. This is the exact reason that I left room for a third panel...just "in case".

As far as battery capacity, I have yet to determine whether we need more. I have the space (above the others) to add two more...OR...maybe a switch to two 12-volt batteries producing twice the amp-hours but with half the plate capacity is the answer. More research is required to determine that.

For now, this is what we have, and we are going to continue to use it until we see that it is not working as well as we would like it to. By then, we hope to know more about the possibilities for change.

Today, we have not only the new 2000-watt pure sine wave inverter coming, but also something else to help our internet access. We purchased a WeBoost 4G-S cradle-type cell phone signal booster that should also be here today. We canceled our phone line-based service while we were gone to Indiana, so all we have is the cell phone hotspot now. On rare occasions we get lucky and get three bars of 4G LTE access, but the majority of the time we can only get one or two bars of 3G. We can't even watch a You Tube video right now. Uploading photos takes the proverbial "forever", and we still have a lot of blogging and other business to take care of, so gaining speed and dependability is an absolute necessity! I sure hope the new booster works as well as the reports say!

The next post will detail our first outing with the trailer, our experiences with towing it as well as using it, the additions we made to it during the trip, our added expenses to making other improvements and repairs to the van while there, and some photos of a beautiful state park we stayed at on the way home! So stick around! It's only going to get better from here forward. Most of the tedious work has been done, and reported in past posts, so if you haven't read about our progress from the beginning, I urge you to take the time to go back to the "New Beginnings" post, where it all started, and read forward. 

Also, don't forget to check the menu items just below the header, as those permanent pages explain more about us, and why we are choosing this lifestyle, as well as why we chose the vehicles we are using.

As far as our timeline, the sorting, packing, and getting everything ready to get out of here is taking WAY longer than we had planned, so I hesitate to even set a deadline anymore, since we have already shot by three of them. We're trying our best to get out of here by the end of October, but in reality, it could be into November before we leave. All I can say at this point is that when it happens, it happens. Our only goal now is to try to beat the cold weather!

One thing that I have not mentioned is that due to the lateness of the season in leaving, it is getting too cold to try to get to South Dakota. The trip to Indiana was already long overdue, and we had to accommodate other people's schedules, so we couldn't delay any longer. With that out of the way, I can now say that we have joined Escapees RV Club, out of Livingston, Texas, a few miles north of Houston. So that is where we will be headed for a few days when we leave here. At least it will be toward warmer weather, rather than colder!

Rather than our planned stops at our new home park in Gunnison, Colorado, and then going through Taos and Santa Fe, we will be heading straight west from Texas toward Yuma, via the quickest southern route. As always, some routing depends on weather, so we will make adjustments as necessary.

As always, thank you for reading, and don't be afraid to comment or ask questions. 


Bradford H. said...

Solar is awesome! I've saved plenty of money using solar. During the coldest of months, the van is plugged in to the house to get a full charge and then when camping the solar keeps the battery bank topped off enough to run the minimum equipment (CPAP machine, TV). During the summer, it's amazing... I'd never need to buy electricity. The best part, as you mentioned, is the freedom. You're not tied to a high priced campground.

John Abert said...

Hi Brad! Yes, solar is the way to go for every RV today, even if they regularly use RV parks with hookups. Even though an engine alternator will normally charge the coach batteries when going down the road, there are always going to be "in between" times when the coach is setting, or in storage. I've heard of cases where park owners have come around and pulled the plug on RVs when no one is there, because they don't want their electricity to be wasted. Having solar assures that you have power available no matter what occurs outside the coach. BTW, I corrected a typo in the post just this morning. The pure sine wave inverter I ordered is a 2000 watt, not a 200 watt. I calculated that ten minutes of running our 700-watt microwave would pull a little over 9 amp-hours from our battery bank, out of a potential 56 amp-hours available (assuming that's 25% of the total amp hours, and before voltage drops to an unusable level.) This will make life SO much more convenient, with being able to heat a quick meal, or water for beverage at rest stops or other points in the middle of the day. With decent sunshine, the solar should put that charge back in long before we get to a night time stop. Once parked for the night, we can always revert to using the propane stove for cooking, rather than wear the batteries down going into the evening hours, when no solar charging will be taking place. It's just a matter of common sense and proper timing and rationing of the power.

Ed Helvey - Location Independent Traveler said...

It's on my "Wish List" too, John. I've thought about carrying a small Honda type generator, but then I have to carry gasoline too. I really don't relish that idea. Space is limited enough in a van dwelling without adding a generator and a large can of gas, not to mention the gas fumes and potential volatility. So, solar seems like the best long term alternative. Mounting it on a high top van presents its own set of challenges. Marshall Ellgas down in FL did a terrific job mounting several full size panels on his high top conversion van. So I know it can be done and done right.

I also like what you said about the tilt arms and the 20% loss of charging potential by not making the panels tiltable. That makes sense to me now, too. Like you said, just add another panel to make up for the lost and then some. Simplifies thought process on this subject. Right now, without solar and without a small generator, if I find myself in need of some charging while parked, I just run the van engine for a while. usually with the hood open. NOt the most efficient way or best for the van engine, but I only do it for limited periods. And, sure, it uses some gas, but so would a small generator and I'd have to run that engine a lot to eat up the cost of a, typically, thousand dollar Honda plus or minus a little.

Good info, John -- you could go into the business of building custom rigs like yours-BUT, I know, we've talked about it, you don't want another business or the obligations, responsibilities and time commitments thereto pertaining. You've even said this may be your last construction project of this magnitude even for you and Sharon. But, great job and inspiring for others.

live free & be happy,