I have been traveling and living full-time in RVs and buses for 40 years now. All of my buses have had a generator capable of running two or three roof air conditioners (A/C) and all other electrical appliances, as well as a better-than-average house battery bank.

My first bus was an MCI MC-7 Combo. At the time, I lived in an RV park and never drove the bus. I was working full-time in an office building, and I never had time to take the bus out. At the same time, I also owned a Sportsmobile camper that I used for traveling when I wanted to go on a short vacation.  The entire roof was covered with solar panels and had sufficient batteries to run the roof A/C for up to two hours, which was adequate to cool down the inside before going to bed.

The MC-7 had a good Onan generator mounted in a bay, but because I was always hooked up to shore power, I only ran it once a month to ensure it would start if and when I needed it.  The park would occasionally lose power, as it was an old RV park in an older town section. But 100% of the time, the MC-7 was plugged into shore power, so I seldom used the generator and had no need for solar. But I could run the bus using the onboard generator when the power went off.

My next bus conversion was an MCI MC-9 Log Cabin bus, which, when I bought it, had no roof air conditioners, but it did have excellent factory over-the-road air conditioning.  This was great when traveling down the road, but once parked, the best I could do was open all the windows and turn on the two Fantastic Fans, hoping for the best.  The good thing was that all windows were left in the bus for the conversion, and most of them opened, so I could usually have a nice crosswind through the interior.

The guy I purchased this bus from primarily traveled in Southern California and up and down the West Coast, as well as to Burning Man in the Black Rock Desert of Nevada. Therefore, he did not need air conditioning once parked, as it was rarely that hot where he camped. However, I bought the bus to live in it full-time and to travel all over the U.S.  So, one of the first things I did was to install two roof air conditioners. They were easy to install in the two roof hatches and were already pre-wired for potential future expansion.

The bus was wired for 30A, but by changing the main breaker and the shore power cord, it could handle 50A of power.  The bus was designed to be upgraded if air conditioners were later installed.

That bus had no onboard generator, so one of the first things I did was remove the working Onan generator from my MC-7 bus and install it in the MC-9.  The guy who sold me the MC-9, Mike Kadletz (some of you may know him), tried pawning off a cheap Chinese generator on me. After I spent a couple of days trying to get it running, I decided to remove my reliable Onan generator from my MC-7, which I was trading in for my MC-9 bus.  The generator ran well and lasted as long as I owned the MC-9. 

The MC-9 came with two 12V house batteries, so I immediately added two more. It also came with a 1,000W inverter. Like the previous owner, I could run everything in the bus off the house batteries and the inverter for a day without plugging into shore power or running the generator. This bus was a fairly basic conversion, which he termed 'Back to the Basics', with only the essential appliances on board. 

But if I wanted to run one or two roof air conditioners, that was a different story. I had to be either plugged into shore power or run the generator.  It had no automatic transfer switch, so to change it over to run on the generator, I had to go outside, open the electric bay, and plug the shore power cord into the generator outlet. Nothing fancy.

At the time, I lived in an RV park most of the time and took the MC-9 on occasional one- or two-week trips, so using the generator worked fine when I couldn't plug in. This bus also carried propane for the heat, hot water, stove, and oven. They were two removable propane tanks, making it easy to get them filled without driving the bus to a propane station. I didn’t have much time to travel in my bus because I was working full-time, so I couldn't justify installing solar on that bus either.

Things were different when I bought the 1967 Eagle, which I still own now. Once I moved into the Eagle, I left the RV park and started traveling more. 

When traveling, I spend most of my time boondocking. I am not a big fan of RV Parks because they are not worth the hassle of checking in, parking, getting everything hooked up, disconnecting everything, putting everything away, and leaving the following day. Also, if I wanted to leave the campground at 4:00 a.m., when I like to start traveling in the morning before the sun comes up, people didn’t seem to cotton to that very well, as my bus was loud.

When traveling, I much prefer boondocking and staying in rest areas, truck stops, BLM (Bureau of Land Management) property, at a friend's house, or sometimes just off an exit on the side of the road.  Staying in these places, nobody cares if I get the itch to start out before sunup. 

I discovered that if you spend most of your time traveling on the red roads, you can usually find good places to stay on either end of many small towns where truckers frequently overnight. The advantage of these locations is that you are generally close enough to a small town to receive a good cell phone signal, making it easy to check email and work on BCM articles and the website.  Also, if someone bothers you at night, the police are not far away…hopefully. However, I have never had a problem, and was never asked to move my bus.

There are no hookups in these locations, so if I want to run my A/C or charge my house batteries in one place for more than a day or two, I would have to run my generator.  Additionally, if I want to run my washer/dryer unit on the dry cycle, the time it can run on my batteries is limited to about an hour, which is usually insufficient time to dry a complete load of clothes.  I sometimes run the generator and do laundry while driving down the road, if I know there will be a fresh water source and a dump station along the way.

The 12.5 kW generator in my current bus, the 1967 Eagle, is enclosed in a soundproof compartment, so it is very quiet. Nobody has ever complained when staying in a rest area, at a truck stop, or along the side of the road, as it is no louder than the refrigerated trailers that run all night. However, when boondocking on BLM land or in other quiet areas, even my soundproofed 12.5 kW generator compartment can disturb the neighbors if I start at 4:00 a.m., when I usually get up. I can hear it too, but it doesn't bother me.

I have considered installing solar panels on the Eagle since I bought it, but could never justify the expense. A solar system adequate to power my bus and run everything, including the three A/C units and my washer/dryer, would require more panels than I have room for on my roof. However, installing adequate solar panels on my roof to run everything except my air conditioner and washer/dryer could be done with the available real estate on the roof. 

Ten years ago, when I first explored this idea, I couldn't justify the $5,000 I was quoted for approximately 2,000W of solar power, which would have allowed me to run everything in my bus except for my air conditioners and washer/dryer. I figured I could buy a substantial amount of diesel fuel to run my generator for that cost. However, solar panels and components' prices per watt have since decreased considerably. Besides that, I began traveling more and no longer claimed an RV Park as my home base.

When installing solar on a bus, you must take into account not only the cost of the solar panels, but also the cost of lithium batteries (to do it right), an MPPT controller, circuit breakers, switches, bus bars, heavy wiring, tie downs, and in my case, a new 4,000W Magnum inverter because the Trace inverter in my bus, installed 25 years ago, was not compatible with the charge requirements of my lithium batteries.  Therefore, I postponed installing solar on my bus for several years.

There are, however, several advantages to installing solar on a bus, more so than on a house.  A house does not require a generator when the sun isn’t shining or a large battery bank to store power, as you are hooked up to the “grid”. In a bus, you need both, unless you are plugged in full-time, which kind of defeats the purpose of owning a bus in the first place. Buses have wheels and are designed to travel thousands or millions of miles, as mine is, and if you travel a lot as I do, and don’t frequent RV Parks, solar is the ultimate way to go.

Also, some generators are noisy.  People who run the commercial generators will drive everyone around them far, far away, and they are not designed to last as long or be as quiet as a well-built RV generator such as EPS. You can hear the cheap generators running a half-mile away. 

The more expensive generators, designed to be mounted in an RV, are much quieter and are designed to run for 30,000 hours before a major overhaul.  30,000 is a lot of hours, but it is not infinite.  If you keep your rig and run it frequently for several years, the generator will eventually require rebuilding or replacement. Neither is cheap.

I don’t have an over-the-road (OTR) air conditioner in my Eagle. Like most bus conversions, it was removed during the conversion because, although you can hang beef in a bus while running, the large picture windows on three sides mean these units are designed to cool a bus load of people and luggage, decreasing fuel mileage. They are also costly to maintain as they age, and bus conversions are non-revenue-generating vehicles like passenger buses, justifying the cost of maintaining the OTR air conditioner.

That being said, installing solar on your bus roof will not only help encourage your neighbors to talk to you again but also save your generator.  Now that solar panels have become significantly more affordable, I finally decided to invest in installing solar panels on my bus’s roof.

I started four years ago with two 24V, 340W panels. I purchased a 60A MPPT controller, as it would enable me to add more solar panels later, and I was confident that I would need to do so eventually.  At that time, I wanted to leave my 12V refrigerator running, keep my batteries charged, and run some 12V and 120V appliances if I was in the bus, or away for a couple of weeks. 

I purchased the components and completed the installation with the help of a friend. We screwed the solar mounting brackets directly into my aluminum roof, using lots of self-leveling caulking. We then ran a 10-4 electrical cable from the back solar panel on the roof to the front cap of the bus, where I drilled a hole and ran the cable down in the front of the bus between the two windshields, and then about a third of the way back through my bays to my house battery compartment.

At that time, I had four 105W Lion Energy lithium batteries, which were much better than the eight 6V golf cart batteries I had before. When the Lion Energy batteries needed charging, they charged much faster, reducing the time I had to run my genset. There is an excellent article about Lithium Batteries being a no-brainer here. 

I ran with that setup for about a year, but as I expected, unless the sun was shining brightly and I was working in my bus all day, I still had to run my generator for about three hours per day to charge the batteries. 

The following year, I saved up more pennies and purchased four additional 24V, 200W solar panels and a second 60A MPPT controller from EEZ RV Products in Ontario, California, which my friend and I installed.  The 10–4 electric cable I originally installed was still sufficient to carry the additional Amperage. Still, I made some other improvements by installing larger circuit breakers and cut-off switches, and we installed bus bars to make the system cleaner. Installing 3-4 heavy-duty welding cables on a battery terminal is not optimal.

I spent an entire year traveling and boondocking, and the two 340W and the four 200W panels provided a total of 1,480W of solar power. I also added two more 105Ah Lion Energy batteries, bringing the total to six batteries capable of storing 630Ah.  Now, working inside my bus for the majority of the day on BCM stuff, on a sunny day, I may only have to run my generator for an hour or two each day. If I only worked a half day, the solar and batteries could keep up on a good day.

Some may say it seems like I have to run my generator quite a bit, considering I have 1,480W of solar and 630Ah of batteries. That would be an accurate statement for most people. However, my Eagle is all electric, with no propane on board. The refrigerator and everything else in the bus run on 12V or the inverter, except the roof A/C units. The 110V washer/dryer is set up to run off the inverter, but only because I removed an ice maker from that space, installed the washer/dryer, and never rewired it. Of course, the ice maker was connected to the inverter so it would run 24/7.

By this spring, I had saved up more pennies and still had some open real estate on my roof, so I visited EEZ RV Products in Ontario to purchase four additional 200W solar panels. Don Chin, the owner, assisted me in installing them. All other components I had installed earlier were sufficient to handle the extra load. 

I split the circuit so that two new solar panels were wired to one 60A MPPT controller, and the other two new panels were wired to the other 60A MPPT controller, thereby splitting the load. The 10-4 cable was still sufficient to handle the load, as I figured the solar panels would never produce 100% of their capacity on a flat roof in the U.S.

By then, I had eight 105A Lion Energy lithium batteries for a total holding capacity of 840Ah. However, while I was at EEZ RV, I replaced the eight Lion Energy batteries with two of Don's 400 Ah lithium batteries to simplify the wiring and reduce the number of connections.  

Additionally, his 400Ah batteries feature a heating element, which activates when the temperature drops below freezing, thereby preventing the batteries from becoming too cold. Lithium batteries are not recommended for use in freezing weather. This will be very helpful if I take my bus on ski trips in the winter months. 

For more information about this 400Ah lithium battery, click HERE for a great review by one of our regular authors.

My roof is now equipped with 10 solar panels, totaling 2,280W. On my roof, I also have three roof air conditioners, one Fantastic Fan, one Maxxfan, and my RV Mogul TV antenna.  I can still walk around on the roof due to the strategic placement of each panel, but one must be cautious.

I also used the mounting brackets that came with the solar panels. With my curved roof, there is approximately a half-inch clearance between the center of the large panels that span the width of the bus, making them all low-profile. That is sufficient to provide good circulation to prevent heat buildup, but not so high off the roof to create a hazard. 

I have seen some people mount their solar panels a foot or so off the roof with brackets, positioning them above their roof air conditioners. The problem with doing it that way, unless you use gussets or some other method to keep them rigid, is that they can easily blow off your roof, as they constantly flex back and forth while the bus is in motion, and the structure will loosen over time.  This has happened to more than one person I have known.  The concern is that when something flies off your roof, it can go through the windshield of any vehicle behind you, potentially killing the occupants.  

Using rigid panels, such as the ones I used, they can be mounted with an air gap underneath, allowing them to dissipate heat while also providing shade that cools the roof of your bus. This keeps the inside of the bus cooler, so the A/C units don’t have to work as hard. But again, they should not be mounted too high off the roof to catch too much wind when driving down the road.

I should mention here that many people have installed mini-split units in their buses.  These units are significantly more efficient and can be powered by a reliable solar array and battery bank.  I have not done this yet, but I may consider it in the future.  I have heard that in the hot Southwest sun in the winter; they can’t keep up as well as basement A/C units or even 120V roof-mounted A/C units. But in cooler climates, they seem to do fine. 

If I do change over to mini-split units, I will likely choose the newer 12V RV/truck-style mini-split, as they are designed to withstand the bumps and jarring of driving down the road. Most mini-spit units are not intended to take all the bouncing around and may fail prematurely if you travel a lot.  

Also, some people mount the compressor/condenser under their buses and sometimes behind the rear wheels, where dust and dirt can clog it. This will severely limit the life of these units. This newer truck-style unit allows you to mount the compressor/compressor higher off the ground, keeping the unit cleaner, allowing it to run for years with minimal maintenance. 

In summary, I did not install solar panels on my bus to save money on fuel for my generator, but it did help. I did it because I like the peace and quiet of being out in nature with no mechanical noise. My neighbors also appreciate the quietness as they are talking to me again. LOL! 

Solar panels will also extend the life of your diesel generator, which is not inexpensive. They also reduce the frequency of servicing, as the generator requires oil and filter changes approximately every 150 hours. So, even if the expense of adding solar may not break even for a few years, the peace of mind it brings to me and others around me is well worth the investment, especially if you enjoy the sounds of nature like I do.

With my current setup, if the sun is shining in the southern part of the U.S. and I use my appliances sparingly, and don’t leave the TV on all day, or use my microwave on battery power no more than about a minute, the 2,280W of solar and 800Ah of batteries I now have are ample power to keep up with my usual daily routine. Which is what I was aiming for.

Yes, I still need to run my generator to run one or more of the A/C units, or if the sun doesn’t shine for a few days, but overall, the money spent on upgrading the solar system and the two new 400Ah lithium batteries, may or may not ever pay for themselves in diesel fuel savings for my generator, but the peace and quiet it worth it when boondocking in a quiet place working on articles for BCM. That, along with not having to buy as much fuel for the generator and not having to service it as much, makes it all worthwhile. 

Should you invest in solar?  Well, that depends.  For anyone permanently parked on a piece of land and with grid power nearby, there is no need to install solar panels on or near their bus. Additionally, labor costs for installing a solar system can be pretty substantial. I did all the work myself, and with the help of friends, but not everyone can do that. 

That being said, solar is a great option if you live in a bus, vehicle conversion, or tiny house, and there is no power nearby. In that case, if you never plan to move the bus or tiny house, it is better to mount the solar panel on the ground, facing south, and angle them for optimal performance. Unlike buses that park in an infinite number of orientations, a bus you travel in will seldom be able to take full advantage of the sunshine.  That is precisely why I mounted as many panels flat on my roof as possible to take full advantage of the available real estate. 

And in case you are wondering, no, my solar panels do not tilt like some people's. I didn’t want to deal with the additional mechanisms and risk them not holding up on a windy day or when driving down the road. 

This raises another point that I frequently observe. Some people mount their solar panels so they hang over the sides of the bus’s roof on each side, past the edge. I purposely mounted my panels so they were set in from the sides of the bus at least six inches. I have heard of too many panels being damaged or ripped off by low-hanging branches on narrow country roads or even city streets, especially when panels extend out past the side of the bus.  It doesn’t take a very large branch to destroy an entire row of solar panels, and not every conversion owner travels on the interstate all the time.

If you live and travel in a bus and spend most of your time in RV parks with full hookups, as most people with high-end coaches do, then you will never realize the return on investment that solar will provide.  Besides, why unnecessarily put holes in your roof and have one more thing to clean and maintain?

If, however, you travel in your bus full-time, as I do, and frequently camp off-grid in boondocking locations, and you don’t want to deal with fueling and maintaining a generator, the noise, or the smell of diesel fuel burning, then solar may be the way to go for your lifestyle. 

I want to thank Don Chin of EEZ RV Products for working with me to build up my system over the years. He is a very knowledgeable and an excellent source for solar panels, lithium batteries, inverters, and all the components needed to connect your system. He can ship most components within 24 hours. 

Don also has a bug tent in Quartzsite every year before, during, and after the Sports, Vacation, and RV Show, where you can check out his products.  Many people visit his tent every year, and are repeat customers as Don takes very good care of them.