That was the goal for our Alto F1743 trailer solar/battery installation project. After almost four years of driving cars powered entirely on electricity, charging them from solar power generated on our house roof and storing some in a Tesla Powerwall battery, the trailer just had to be powered entirely by electricity generated from solar and stored in batteries, available as needed. (Photo below: my roof with 9.8kW of panels which means I pay my utility only the minimum $10/month grid connection fee)
Going 100% electric is almost unheard of in the world of campers and RVs, but it has been done; Canadians Rolf and Silke Sommerfeld did it with their Alto, which they tow with their Tesla Model X; see TeslaXCanada.com.
Rolf managed to get a total of 800W of flexible solar panels on the roof of their Alto 1723 trailer and used LiFePO batteries that could store 400Ah . His panel layout of eight 100W panels meant there was still some empty roof space. I wanted to use every square inch of roof space, and I wanted even more battery storage capacity.
Using five different sizes of flexible solar panels, procured from a variety of sources, Dan and his able assistant Tony at Quality RV Solar in Fremont, California, managed to squeeze 1,035W of Elfeland panels onto our trailer roof! Some of them fit so well that it looks like they were custom made, but they are all stock sizes.
For energy storage, we were able to fit two ReLiON RB300 300Ah LiFePO batteries (a total of 7.68kWh at 12.8V) in the space under the port side dinette seat which is at the front of the trailer. That’s well ahead of the axel, so their 83 lb (each) weight helped keep the tongue weight up, which had decreased slightly since we removed the factory lead acid battery from it’s location outside the trailer on the tongue. This photo shows the new batteries viewed from inside the trailer; the external hatch cover for this formerly empty storage space is behind them. Having LiFePO batteries inside the trailer is advantageous compared to putting them outside on the trailer tongue: if they get below freezing they won’t charge (though they will still be able to discharge).
The solar panels are controlled using a Victron SmartSolar MPPT 150|85 connected to a Victron Color Control Monitor display (see photos below) showing battery charge status, solar panel output, and energy flow between the panels, batteries, shore power, and AC loads (it doesn’t show DC loads such as the fridge or lighting, but they are minor). And since this is the 21st century, there is a Bluetooth-connected phone app that shows the same information.
Photos courtesy of Quality RV Solar.
Of course that stored energy is in a 12V battery, and there are all kinds of 120V items one wants to use when trailer camping away from an RV campground electrical supply: AC/heat pump for cabin cooling and heating, microwave oven, coffee maker, hair dryer. 😉 That means you need an inverter to turn the 12V battery output into 120V power. So an Energy Multiplus 12/3000/120-50 Inverter/Charger that can output up to 3000W of AC power is part of the system. The inverter, solar controller, and other items are mounted under the port side rear bench seat (which converts to a sleeping area). In this photo the trailer’s water pump is at the upper right in the walled off compartment, the inverter is at the upper left, and the solar charge controller is at the lower left.
Protecting all this hardware from surge voltages and line instabilities is a Progressive Industries EMS30C unit, because it would be a bummer to have a lightning strike or a poor quality campground outlet damage the system! It’s the large black box at the lower right in the photo above, next to the master shutoff switch.
Dan and Tony at Quality RV Solar did an amazing job installing all that hardware. They are perfectionists!
The system works wonderfully well. I leave it on all the time and a glance at the display tells me what I need to know about the system status. The batteries are charged by the solar panels while we are driving or while parked (they can also be charged from shore power if necessary). The 12V fridge draws so little power that I keep it running continuously, even when we’re not using the trailer and it is parked in our driveway; after all, the sun shines every day and the electricity is free.
We do not use the two-burner propane stove that comes standard with the trailer, and if Safari Condo would have built our trailer without it I would have been thrilled, but they would not remove it. For cooking we plug in a single burner 120V NuWave induction cooktop. It draws 1300W max, heats up very quickly, and is quite efficient.
To heat the trailer interior we normally use the standard Truma combi eco heater on electric power (it can also run on propane) which also heats water. It slow to heat up on electric, so we plan ahead as to when we will need hot water. Interior heating and cooling is also available using the Dometic Cool Cat 10,500BTU unit though it draws 1038 to 1330W, so when off grid we can’t run it all day.
Viewed from a purely economic perspective, the high cost of this system will never be recouped by avoiding buying propane. Which of course, is not the point. Human civilization has to transition to sustainable energy. Climate scientists overwhelmingly agree that if we continue to burn fossil fuels at our current rate for the rest of this century, future generations will live in an increasingly inhospitable environment. It won’t just be a little hotter; it will be a nightmare. Productive agricultural land will be lost forever as it is replaced by deserts (which is already happening). Permanent droughts in heavily populated regions will cause social instability, violence, and refugee crisis (currently happening in the Middle East and Africa, and it will get much worse). Reduced snowfall will reduce fresh water supplies that have been relied on for centuries. Rising sea levels and ferocious hurricanes will make coastal cities uninhabitable and they will be abandoned, at a massive cost. Increasing ocean acidity and temperature will fundamentally alter ocean food chains and result in fisheries collapsing (already underway).
That description is not a silly Hollywood disaster movie. It is what will happen if we do not stop burning fossil fuels. It’s simple chemistry: more CO2 and CH4 in the atmosphere equals rising temperatures because of the greenhouse effect, increasing ocean acidification, and greater climate instability compared to the last 10,000 years when human civilization took root. The data is clear:
CO2 levels have been stable for thousands of years until just the past two centuries, which coincides with the Industrial Revolution and the rapid adoption of fossil fuels on a massive scale.
Humanity is currently running the dumbest chemistry experiment ever: adding massive amounts of carbon into the atmosphere, which cannot be removed and will be present for thousands of years, and waiting to see what will happen. But we have known what will happen since the 1970’s when the fossil fuel industry’s own scientists published internal studies showing the likely outcome; rising global temperatures, rising sea levels,, and changing ocean chemistry.
We only have one atmosphere and one ocean, and every person on earth, every species on earth, depends on it. We still have time to save it. Sustainable energy, from wind and solar, is becoming less costly to implement and with battery storage, easier to use. In parts of the American Midwest, wind power is so cheap that at night electricity is free. Commercial scale solar installations are economically competitive with natural gas power plants. Tesla has installed cost effective grid-scale battery storage facilities in Australia and California that store energy and release it when needed.
The sun doesn’t always shine, but it does always rise and it’s free. The wind doesn’t always blow, but it’s not going away and it’s free. Battery storage is the final piece of the renewable energy puzzle and it’s being solved right now.
There are solutions to climate change. We just need to have the will to implement them.