Solar–simplified!

The other day I heard about an educational seminar on the topic of solar power for Airstreams and decided to take a look. What I saw horrified me: the presenter turned this simple topic into an engineering class that would intimidate all but the geekiest among us. Imagine densely-packed slides full of numbers and technical terms.

Solar is easy. Don’t let anyone tell you differently. The sun shines, solar panels convert the sunshine into electricity, and that charges the batteries in your Airstream. That’s it.

The rest is stuff that only a few people really need to know. If you enjoy having all the details and talking about amps and volts (like me, I have to admit) by all means have fun learning everything you can, but I think most Airstreamers just want to get more camping time without having to find a plug or carry a generator.

Let me answer a few commonly asked questions:

“What can I run on solar?”

I often hear comments and questions from people who don’t understand exactly what solar panels are doing for them. At the risk of repeating myself: the solar panels charge the batteries. Solar panels don’t do anything else. So you don’t run anything on solar.

The batteries in your Airstream are actually doing the work of powering things when you’re boondocking. In my book “The Newbies Guide to Airstreaming” I have charts that show exactly what the batteries are powering. (In the 4th edition of the book you’ll find that chart on page 20.) Basically, if it runs on 12 volts, the batteries are powering it.

“Can I use the inverter?”

Sure. The inverter really has nothing to do with solar. It uses the battery’s energy to power the electrical outlets in the trailer. In other words, the inverter makes it possible for you to use things that have plugs, like the TV, DVD player and your laptop, when you’re boondocking—at least until the batteries run down.

Keep in mind that devices that plug in generally consume a lot of energy, so you should use them sparingly when you’re using the inverter. (I’ve done a more detailed blog on inverters which you can read here.)

“What size of solar panel system should I get?”

Unless you’re planning to camp off-grid for long periods of time, you don’t need a particularly large solar array. You can get a lot of benefits from a simple, plug-and-play portable solar setup like this one. You just unfold it, point it at the sun, plug it in, and walk away.

Solar panels are usually rated in terms of watts. The watt rating is really only useful for comparing one system to another since the actual energy generated on a given day varies depending on factors like cloudiness, time of year, and latitude. Personally, I wouldn’t bother with a system of fewer than 120 watts.

“Should I get solar or a generator?”

It depends on how you camp or travel. If you need to run things that consume a lot of power (like an air conditioner, microwave oven, hairdryer, CPAP machine, etc.) when you’re away from hookups, a generator will probably be the best choice.

But if you just want more battery power, solar has big advantages:

  1. Free energy from Mr. Sun
  2. Blissful silence
  3. Extended off-grid camping time
  4. No heavy generator or gasoline cans to carry

If you want more detail on this topic, check out this blog I wrote earlier.

“Should I get portable panels or a rooftop (permanent) installation?”

I wrote a separate blog about this topic, so if this is your question, click here.

“How do I know how much power I have?”

Sometimes people want to know how much power their panels are generating, or exactly how full their batteries are. This is entirely optional, but in this case, I recommend installing an amp-hour meter such as those made by Victron (BM-7xx series), Xantrex (Link series), Bogart Engineering (Tri-Metric), etc. These are much more useful than having a monitor on the solar panels themselves.

If you are less concerned with exact numbers, you can get by just fine with the built-in battery meter that came with your Airstream. It isn’t terribly accurate but it’s close enough for casual use.

To be honest I don’t even look at the numbers anymore. I just plug my solar panels in for the day and as long as we get a few hours of sunshine I know we’re fine for another day at least. (I could explain the math behind this, but I’m trying not to go down the rabbit hole of numbers here.)

“Do I need to upgrade the batteries?”

For most people, no. There are two cases where you should replace the batteries in your Airstream:

  1. They’re worn out and not taking a full charge anymore.
  2. You’re going to install a solar panel system larger than about 200 watts. In this case, you’d find there are a lot of days when the solar panels are producing more power than you can store, which means you’d have a lot of solar capacity that you can’t use. If you’re installing more than 200 watts you’re probably paying a fair amount to install rooftop panels, so you should talk to the RV solar specialist that is doing the work. They can help you match the battery bank to the capacity of your panels.

Bottom line: Solar is easy. Take in the free energy that the sun gives you and go enjoy your day.

 

If you want to check out my pick for a really simple and lightweight solar panel system, look here.

Comments

  1. steven bacus says

    We have two solar panels on top of trailer….when traveling how can I charge batteries – is there some switch that needs to be on?

    Thank you,
    Steve & Marty
    new owners

    • RichLuhr says

      Usually the solar panels automatically charge the batteries without any action required by you. If you have a battery monitor you can see the effect of charging: voltage (or amperage, depending on the type of monitor you have) will go up when sun is shining on the panels.

  2. Marietta says

    Thank you for the great & simple explanation on solar panels. It really helped me understand how it all works together.

  3. says

    1) So how do you use the inverter when you are boondocking?
    2) My portable solar panels have a charge controller built-in and I do have to know what type of batteries to set up the charge controller.
    3) The solar panel/charge controller combination will not charge batteries that are below 10 volts – is that common?
    Thank you for the blog, Ron

    • RichLuhr says

      1. On late model Airstreams with built-in inverters, there’s a panel on a wall somewhere (often near the TV) with an On/Off button for the inverter.
      2. Take a look at the batteries to see what type they are. Most Airstreams have standard “wet cell” batteries like a car. Some have AGM batteries that look similar but will say “AGM” or “Absorbed Glass Mat” somewhere on them. For either of those, the setting on the charge controller should be the same. If you have lithium batteries, they’ll be clearly marked as well.
      3. Yes, batteries that are below 10 volts are DEAD DEAD DEAD, and make not take a full charge ever again. Before they reach 10 volts most things in the Airstream will stop working, so this is not a common situation. You will need a battery charger that is specially designed to recharge dead batteries. Solar charge controllers may not be able to handle this situation.

  4. Frank Cates says

    SOLAR. I like your presentation in such a way as to help folks save & not be wasteful of their funds. Sure there are outfits out there who’d like to sell you the Moon or the Sun. I have one 90 watts Solar roof panel on my F C. 23CB. I also have a 3400 watts Champion gasoline inverter, so don’t have to buy any more equipment for the time being. Thanks for the good tips.