Solar-Power Survival in Yosemite

Aerial view of truck and trailer parked along sidewalk with solar panels
Installation of solar panels on the roof of our RV was a simple part of the project to create a self-contained power system. Photo: Alaina Elliott

Off-the-grid lessons learned from one family’s DIY solar install

Last fall, our family embarked on a journey across the United States in our 30-foot Winnebago travel trailer. We knew our trusty Toyota Tundra and Winne Minnie Plus would keep us safe on the road and in the wild. But there’s always room for improvement, and one modification we decided to make before departing was a completely self-contained power system that included solar panels for charging a lithium-ion battery bank.

The project took about 50 labor hours and a healthy budget. When completed, we felt confident knowing we could generate our own power. This would allow us to journey into the most beautiful and untamed parts of the country while maintaining the safety and comforts of home. Little did we know, we’d soon be putting our hard work to the test.

Always Field Test First

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The first real field test of our self-contained power system was in Yosemite National Park in December. As you might have guessed, Yosemite in winter isn’t an optimal scenario. Let me explain how we found ourselves field testing our only means of power in snowy conditions in the semi-wilderness that is California’s Yosemite Valley.

This occurred on the middle leg of our cross-country trip. We’d spent the fall meandering northwest through the Teton Valley in Wyoming, across the sand dunes in Bruneau, Idaho, and through Oregon’s eastern high desert. During this trek, we were lucky to camp at many well-appointed RV resorts and also had sunny boondocking days. We’d been so busy enjoying the full hookups, Wi-Fi, hot tubs and saunas — along with the sunshine and a full battery charge — that we neglected to confirm whether or not our next stop in Yosemite had power. We discovered that bit of crucial information only after we pulled up to the campground gate. The ranger asked with eyes round and full of concern, “You didn’t know that Yosemite campgrounds are dry camping only?” I confidently responded, “Don’t worry, sir, we have a whole off-grid power system!”

We learned a very important lesson during our stay in Yosemite: testing DIY modifications is critical to your ability to stay safe in challenging camping conditions.

Two kids playing in snow with red travel trailer in background
Despite cold temperatures and power challenges, we had an amazing time field-testing our DIY solar system in Yosemite National Park. Photo: Alaina Elliott

Components You Need

OK, before we discuss the next episode of our Yosemite adventure, let’s get into the basics of installing a solar system.

Find Good Sam Parks in Yosemite

While implementing our DIY system, we fell into the same confusion that afflicts many of our fellow DIYers: “So we understand that we need solar panels and we need batteries, but what else do we need?” The biggest mistake we made was not understanding the difference between the solar charger and the inverter/charger. Initially, we did not purchase a solar charger because we thought that the inverter/charger we purchased included the solar-charger functionality. That turned out to be a mistake. We soon realized we did need both an inverter/charger and a solar charger.

Here’s the complete list of system components:

1) Solar Panels — Do the math for what you need. We went with a 400-watt setup and have enough roof space remaining to double that if we choose.

2) Batteries — After a lot of research, we went with LiFePO4 lithium-ion batteries. They’re much more efficient (and expensive) than lead-acid batteries because they can be discharged to much lower levels without risk of damage. This means that if you have a 100-amp-hour lithium battery, you will get nearly 100 amp-hours of power. This compares favorably to a traditional lead-acid 100-amp-hour battery, where getting 50 amp-hours is a good outcome.

3) Inverter/Charger — This is the core of your battery system. It converts 12-volt DC battery power to 120-volt AC power. You need one of these to run your AC-powered equipment, like the microwave or coffee maker, from battery power. You also need one of these to charge your batteries when plugged into shorepower. We went with a 3,000-watt inverter/charger, and this provides just enough horsepower to allow us to run the microwave while we watch television. However, it’s not enough to also run a hair dryer while running the microwave and a TV. Breakers will flip for sure in that scenario.

4) Battery Cables — Do not skimp on battery cables. Get the correct size as specified by your inverter/charger. You can blow fuses and even cause a fire if your battery cables are undersized. Our system required 4/0-gauge battery cables.

5) Solar-Charge Controller — The solar charger functions independently from the inverter/charger. The solar charger is connected directly to the batteries and enables the charging of the batteries by harvesting power that the solar panels generate. The solar-charge controller ensures that your batteries charge within the specifications they were designed to charge in. The charge controller ensures that the batteries are not overcharged and keeps them topped up via a “float” routine when they are fully charged. You must have this component if you want your solar panels to be able to charge your battery bank. You need to be as efficient as possible in harnessing that energy from the sun. Consider purchasing the most expensive charge controller you can afford. Every watt you harvest counts when you depend on your off-grid power system.

Components You May Not Need

There are a few items we chose not to include in our system. Because we elected to disconnect our RV’s ability to receive a charge from the truck’s alternator, we did not need to install a battery-isolation manager. Because we chose LiFePO4 batteries and did not worry about damage caused by low voltage, we did not purchase a battery guard used to automatically disconnect the battery at a certain low voltage. Lastly, we chose our inverter/charger’s install location for its easy access. That allowed us to forgo purchasing the remote-control add-on because we could just turn it off and on manually at the inverter itself.

Running Air Conditioning and Heat on Battery Power

There are lots of tips and success stories about enabling RV air-conditioning units to run off battery power. It can certainly be done with the help of some type of easy-start soft starter, which will ensure you don’t blow fuses during the first phase of starting the air conditioning. We had to stop and ask ourselves if it was worth it. The air-conditioning system pulls a tremendous amount of amps and would drain our battery bank very quickly. The only way to work around this is to have a much, much larger battery bank than is required to run the rest of your AC-powered systems. If we chose to go with top-of-the-line lithium-ion batteries, we would have been looking at north of $10,000, just for batteries. If we attempted traditional lead acid to reduce costs, we wouldn’t have had room on the rig.

As we progressed through our solar research, we decided to discard any plans to try to run the air conditioning off the batteries. We saved a lot of time and money by instead designing a trip that kept us in cool weather where we would need only our MaxxFan system and open windows to stay comfortable.

What about heat? The battery bank has no trouble handling the furnace. Because most RV furnaces run on propane, the electrical demands are very low. The only electrical requirement is a small draw to keep the pilot light running. The takeaway here is that you can plan to be in cold weather on batteries only, but consider that your boondock planning should keep you out of the heat of high summer as well.

Freedom from a Generator (But You Still May Need One)

Prior to arriving at Yosemite, our power system had worked so well that we hadn’t even considered that we might need a generator. We spent many nights boondocking in Walmart parking lots with no hiccups, so having a generator seemed like a waste of precious cargo space. But thanks to our cloudy and snowy experience in Yosemite, we gained an appreciation for having power at the pull of a starter cord. We’ve also come to deeply understand why most RVers dislike generators as a necessary evil.

We became generator owners when we realized we couldn’t risk another cloud-blanketed day in the shadow of Glacier Point. Our solar panels generated 10 to 20 watts and only a few amps of power, which was not remotely enough to provide a lasting charge to the battery bank. Clearly, that ranger at check-in understood that our solar gear was inadequate for those conditions.

So on the morning of day three, we made an emergency run out of Yosemite Valley on California Route 140 heading west. At the time, Route 140 had a road-condition status of R1. For native Floridians like ourselves and others from warm climates, R1 means snow chains are required but snow tires are allowed. We had neither, but we do drive a 4×4 Toyota Tundra, so we decided we could make it. Shortly before 10 a.m. on a snowy morning, the whole Home While We Roam crew set out to obtain a generator in Merced, some two hours away.

We were triumphant in our return to the valley at around 4 p.m. with our newly acquired generator. But this new piece of hardware — like the evil beast it is — quickly wiped out the levity from our moods. The generator started nicely on first crank after being filled with fuel and oil. Oh, but the noise! Its engine’s roar ruined the winter tranquility that came with being one of only two RVs in the last open section of Yosemite’s snow-covered Upper Pines Campground.

Prior to this, for the first two days of the visit, the only noise we’d added to the environment was the laughing of our children and the barking of our dogs. Then we found ourselves dependent on a roaring machine that slurped dirty petroleum products with no regard for where its next feeding might come from. Thankfully, the National Park System has the good sense to know these beasts can’t be left to run free and must be contained to morning and evening exercise sessions only.

On day three of our nine-day stay, we realized why the solar lovers prefer off-grid power to combustible engine-generated electricity. It isn’t about saving the earth and being the best “you” you can be. It’s about preserving the freedom that you seek from being in a remote destination in the first place. You begin to live by generator hours. You don’t dare wake and go for a hike because you might miss the full two hours needed to charge, meaning you may not have heat when night falls. Instead of looking forward to a snowy visit to the meadow in front of El Capitan, you wish the snowstorm will break so you can make yet another journey over R1-rated Route 140 westbound to the closest fuel station, 35 minutes away.

The generator is the giver of heat but robber of freedom. It’s something to contemplate as you consider a DIY RV solar project.

Yosemite mountain on cloudy day
Half Dome in a winter-wonderland Yosemite National Park. Photo: Alaina Elliott

What Have We Learned Living on Solar?

Hands down, the greatest benefit we’ve received from our self-contained power system is freedom. Can we demonstrate a return-on-investment for the system install versus savings from more boondocking?

If we didn’t say it was challenging, we wouldn’t be honest. This power system was expensive! But it gets a lot easier to justify when we consider the nonmonetary benefits of our solar-powered energy system. About 99 percent of our trips don’t involve the weather conditions we experienced in Yosemite, and this is where solar really shines. Very soon after the weather in Yosemite challenged our solar power system and won, we were back out to the Pacific coast, staying on Ventura, California’s Rincon Parkway with no campsite electricity and had no troubles.

We never worry about getting a generator out and chaining it up to the rig or annoying our neighbors with generator noise. We never worry about having coffee in the morning or being able to microwave a snack for the kids. As long as the sun is shining, we feel a freedom unique to life in a self-contained solar-powered RV.

Young couple smiling wearing hiking gearHome While We Roam is an Atlanta, Georgia-based family who love RV life. They’ve traveled more than 15,000 miles around the United States with their red Winnebago Minnie Plus travel trailer in search of simpler living, deeper family ties and epic adventures! Find them on Instagram @homewhileweroam.

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  1. I have a generator similar to yours — loud. Others I know have gone with the Honda or similar very, very quiet generators, and they can barely be heard. They cost two to three times more than the noisy ones but solve some of the generator problem. Thanks for the article. It was helpful.

  2. Good write-up for novice users. Something here that I always question with new solar users: Why 12V? I know why, but trying to get 3,000W out of 12V is really hard and not much fun. You are looking at 200+ amps. Even with 4/0 wire, it won’t be happy, and you won’t have the ability to run very long. Would love to hear your reasoning.

    • If we understand your question and good idea of running a higher voltage at a lower amperage, I think our answer is that we were just such rookies at the time that we didn’t consider that as an option.

      With the benefit of hindsight, I think cost and battery bank storage would be our biggest challenge. More voltage means more batteries in parallel to achieve the same AMP Hour capacity. So if we had a larger budget and more storage, running at more Voltage to reduce our amperage would be a good area to explore.

  3. Sam, good article, but in one place you could be more correct. The LP furnace in a camper actually uses a LOT of 12-volt power for the blower fan. When dry camping in cold climates, the heating system alone can overwhelm a 12-volt battery bank. Ask how I know. 🙂

    • Use a separate Olympian Wave 3 mounted catalytic heater instead. Puts out a soft red glow to see at night, heats objects not air, uses propane, and will not burn up the oxygen with a ceiling vent opened slightly. Toasty!

    • Hi, Jim. I won’t ask how you know, but can guess. That is a good point. Next time we are in the snow, I’ll spend some time gathering some metrics and see what kind of impact we are having.

  4. Congrats on the upgrades, and thanks for a great article; very helpful! I’m curious: what was the total weight of the whole system, including panels, fans, batteries, etc.? I’m wondering how much CCC you lose in exchange for the system (and additional tongue weight, if known).

    • Total weight of the system including the four panels and heavy inverter is under 200 pounds. Since we removed the factory lead acid from the tongue, our incremental is ~150 pounds with no added tongue weight. Batteries and inverter are cleverly stored in unused space in the rig’s living area (thanks to my install partner’s ideas).

  5. I have a very large truck camper with a 100-watt solar panel and built-in Onan propane generator, air-conditioning/heat exchanger, two 6-volt golf batteries, normal camper heater, catalytic heater, fully loaded with 10-cubic-foot refrigerator, microwave oven, etc. Fully self-contained at over 5,000 pounds loaded on a Dodge one-ton 4×4 SuperCab Cummins diesel pulling a 16-foot trailer with down ramp and two Honda ATVs, and a 2,000-watt Honda EU generator/inverter. Total integrated solar, two separate quiet generators (idles down and ramps up on demand), propane backup, truck with two large batteries and charge backup to camper. I go where the stars shine at night and leave liberal crazies behind. Love it to the fullest.

  6. You have no idea how helpful this article and the responses were to us. We are 15 months out from our planned excursion. One primary aspect of it was solar power, which we will integrate in whatever RV/trailer we decide to buy. A lot of food for thought here. Thank you, we appreciate your advice. Will follow you on Instagram.

  7. When you decided you needed a generator because of lack of sunshine, why didn’t you connect your trailer’s cable to your truck and run that to charge up? Also, the Honda 1,000- and 2,000-watt generators are very small, light, fuel efficient and quiet. I have a truck camper with a single solar panel, which is sufficient to keep my batteries charged when I use the Fan-Tastic Vent roof fan and other light use. My refrigerator is three-way, allowing me to use propane, DC or AC, which I run on propane when boondocking. When it’s cold I use a Mr. Heater that runs on propane 1-lb. tanks or hose to the main propane tanks. But I also use the onboard propane furnace to initially remove the chill if we’ve been out and away. Then I periodically run a Honda EU 2000 inverter/generator if I want to run the coffee or microwave and to charge the batteries if I’ve drawn too much for the panel to charge up in a reasonable amount of time. Another nice feature is to use the remote start of my GMC pickup to fire up the truck and provide power to the truck camper if I’m too lazy to go outside and start the Honda during the night. I consider this a hybrid system, and I would bet the cost to set up is much less then a full solar system, as you’ve described, especially considering you needed to buy a generator anyway.

    • Hey, David. My first excuse is that we are Florida natives and hadn’t done a great job of considering the impacts of camping in freezing conditions. The real reason is we actually disconnected our alternator connection from the truck since we didn’t trust dealing with different charging voltages of having lithium and the lead-acid from the truck when we installed the system. That decision saved us from having to install a battery isolation monitor like this one

      Hindsight in the snow, I wish I could have plugged in and charged from the truck!

  8. I have a 1992 Kit 22HT with 400 watts of solar integrated with an IC2000 Go Power system. Required only 2/0 wire and an additional breaker box. It is a completely off-grid system and uses Renogy panels — super efficient, even it there are clouds. It tops off my batteries in four hours. Four Renogy 40-amp MPPT gels. Not the most expensive or efficient, but it all works great as long as I don’t leave anything on, LOL.

  9. 300 watts on the roof with dual 100-Ah batteries with PWM controller. Portable 3,000-watt inverter that the trailer plugs into. I have two additional 100-Ah batteries in the truck that I can add to my trailer bank to expand capability. Also carry a Firman 3300i genny that the trailer can plug into. Runs everything. Works for me.

  10. Five years ago we purchased a 100-watt solar panel with controller that we attach to our batteries. It is not mounted on the trailer. We are able to position the panel anywhere in our campsite that gets sufficient sunlight since adding additional wire between the controller and the panel. We just got back from a nine-day trip to sunny central Oregon, where we had plenty power to run everything except the microwave and air conditioner. We do have a (loud) generator in case we need it, and in five years have used it once for two hours. Being able to move the panel has been key many times!

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