Adding Solar to your RV - Part I

Solar panels are increasing in popularity for homes across the United States. These are also becoming an increasingly popular choice among RVers, as well. After all, an RV is just a small home-on-wheels, so why shouldn’t it also benefit from the experience of having solar? Solar is a clean, free (after the initial cost of installation) energy source that can really enhance an RVer’s experience, especially if they’ve  boondock or are more interested in boondocking. 

As a reminder, boondocking refers to camping without hookups. However, forgoing hookups does not necessarily require a lack of access to resources, such as electricity. Nearly all Harvest Hosts locations are boondocking-only, but this is where installing solar panels on your RV can come in handy. To be fair, some many RVers use generators to charge their batteries, but this method of receiving power can be expensive, loud, and bad for the environment.

For those who boondock often, solar is a great investment that allows users to combat excessive generator usage. If you are considering installing solar on your RV, then this article is for you. Grab your calculator and let’s do the math to see how much solar your RV will need. This is the first part of two in our series about solar panels, so keep an eye out for the second article following this one.

How does Solar Energy Work?

Everyone knows that solar panels convert sunlight into energy. But what happens after that is not so easily understood by most. In essence, the solar panels absorb the sunlight which creates an electric current that goes through the charge controller, which controls how much current goes through to the batteries for storage. The RV batteries produce DC power by default, and an inverter converts the power from DC to AC, which is what powers most household items like chargers, the TV, etc. 

How Much Solar does my RV Need?

Tools

The amount of solar your RV needs will depend on how much energy you use on a daily basis. Generally speaking, most solar setups are not equipped to run large appliances like air conditioning. On the other hand, many boondockers choose to visit temperate environments to savior excessive heat and cold. 

For a quick rundown, there are several online RV solar calculators like this one from GP Electric. The most accurate way to determine your power usage is to utilize a battery monitor or power meter. A battery monitor, like this one from Victron, can be installed onto your aux batteries and connects to your phone or computer via a bluetooth app. The user can keep track of how much power they use on a daily basis and how this affects the batteries' charge. This technique works best if you take your RV out to boondock for a day or two. A battery monitor is a great tool to have even after your solar is installed, sothis is not a bad investment if you choose to go this route. 

A power meter, like the one from Lanmu, allows you to plug in a device and it records its power usage. If you only intend to use a handful of power-drawing deceives in your RV, then a power meter can be an affordable way to determine how much power you require. Be sure to take into account your water pump, converter, lights, chargers, fridge, and any other power-drawing items in your RV. 

Calculations

Once you determine your daily power usage, then you can begin to calculate how much solar your RV will need. On average, a 100-watt panel can produce about 6 AH (Amp Hours) in direct sunlight per hour. If your RV is situated in a good, sunny spot on a cloudless day, the maximum number of hours of direct sunlight is 5 hours per day. Therefore, one 100-watt panel can generate up to 30 AH per day. On average, two adults using a modest amount of energy, require 3 100-watt solar panels. But this number can vary greatly depending on how much energy you will need to boondock comfortably.

Accessories

Charge Controller

A charge controller is where the solar power goes right after it’s absorbed into the panels. These devices manage and regulate your current, while also offering a breakdown of how much power is being absorbed. Charge controllers also help to prevent your batteries from overcharging. 

There are two types of charge controllers: a pulse width modulation (PWM) controller and maximum power point tracking (MPPT) controller. A PWM controller works similarly to a switch. When the batteries have reached their full charge, it’s switched off. When the battery charge begins to lower, it switches is on again. 

MPPT controllers utilize an algorithm to allow the panels to operate at the most efficient voltage and temperature, extracting that power to charge the batteries. If your RV will be utilizing a large amount of solar, then an MPPT controller can actually increase solar output by up to twenty-five percent.

Inverter

All battery power in an RV is stored as DC power, and DC powers lights, water pumps, fans, radios, and a few other accessory devices. Shore power is AC power, and, when plugged into shore power, your converter charges up your batteries. Solar power begins as DC power and needs to be converted into AC power, which is where an inverter comes in handy. The size of the inverter depends on how much power will be used. To quickly determine the size you will need, use a battery monitor or a power meter to calculate the total wattage you’ll need to power your RV, plus an additional twenty percent.

Once you have determined what size inverter you need, there are two types to choose from. Sine wave inverters are the most popular choice because they are the strongest and most powerful. These can power almost any device and are also the most expensive type of inverter. 

Modified sine wave inverters are less powerful than sine wave inverters. However, they can still power most devices in your RV. Modified sine wave inverters consume more power than sine waves but are more affordable. We know that was a lot of information, but don’t be too intimidated. Adding solar panels to your RV can take a lot of forward-thought but can also relieve a lot of future headaches. This handy upgrade can allow you to boondock in beautiful, remote locations while still having access to power. Stay tuned for our next article when we cover the types of solar panels, installation, and additional considerations.Do you have solar on your RV? How many watts? Are you considering it? Feel free to share your experiences with solar below!