We’ve put together this Helpful Guide to Understanding Solar Power for Van Life or RV Living to help clarify a lot of the seemingly confusing aspects of solar power. In this guide, we’re going to try and cover all of the main components that make up a useful solar power system for van lifers and folks who live in RVs.
If you’re planning on living a more nomadic lifestyle or just want to learn a little about solar power this guide will be a great launching point! We’d like to note that we are not electricians but we’ve gathered all of the information while building a solar system for our own converted van. You can see our build here.
Let’s get started!
What is solar power?
Solar power is the ability to convert the sun’s rays into electricity.
There are different ways to use the sun’s rays to create electricity; the main one we will be focusing on is creating solar energy with photovoltaics.
Ok, and what are photovoltaics?
Well, to put it simply they are substances that have the ability to convert solar rays into usable electricity.
What are the basic elements of a solar powered electrical system for a van or RV?
There are a few basic pieces to every solar setup. Your solar needs can be very complicated or very simple but in all cases you will always require the following items to get started:
Proper solar power installations can include inverters, breakers, kill switches, various sizes of wiring and many other items based off of your power needs. You’ll have to source the necessary parts so you can build a system that can handle the amount of electricity you plan on consuming.
In some cases your power needs outweigh your personal budget for the solar power setup so you may want to consider a generator if your power needs are high and your budget is low.
Let’s learn some basic terminology about solar power & electricity.
Here are some basic definitions as defined on Wikipedia.
Watts
Power is the rate at which energy is generated or consumed and this can be measured in a unit called a watt.
Still want to know more? Here’s a link to wikipedia.
Volts
Volts are the unit of measurement that tells us the amount of electrical potential something has. One volt is defined as the difference in electric potential between two points of a conductive wire when an electric current of one ampere dissipates one watt of power between those two points.
Still want to know more? Here’s a link to wikipedia.
Amps (Ampere)
An ampere or amp is the base unit of electrical current.
Still want to know more? Here’s a link to wikipedia.
Ohms
Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
Still want to know more? Here’s a link to wikipedia.
How do I calculate all of these things?
This is Ohm’s Law Triangle. Ohm’s Law states the relationship between voltage (V), current (A) and resistance (Ω).
And the Watts Law Triangle. Watts Law states the relationship between power (W), current (A) and voltage (V).
Series Circuit
This is a type of wiring technique that creates a circuit where current goes through every component of the setup. All components in a series connection carry the same current.
Still want to know more? Here’s a link to wikipedia.
The basic takeaway here is that if one of the lights dies in this circuit the whole circuit will be interrupted. A great example of a series circuit is old Christmas lights. When one light dies you have to find which blub popped and replace it to get all of the other lights to turn on again.
Parallel Circuit
If two or more components are connected in parallel, they have the same difference of potential (voltage) across their ends. The potential differences across the components are the same in magnitude, and they also have identical polarities. The same voltage is applied to all circuit components connected in parallel. The total current is the sum of the currents through the individual components, in accordance with Kirchhoff’s current law.
Still want to know more? Here’s a link to wikipedia.
With a parallell circuit we don’t have quite the same concerns as with the series circuit. If one of the lightbulbs stops working it won’t turn off the others.
AC Power
AC stands for alternating current, which means the electrical current frequently reverses direction. AC electricity is measured according to its cycles, with one complete cycle being counted each time a given current travels in one direction and then doubles back on itself.
Still want to know more? Here’s a link to wikipedia.
To use the AC power in your solar setup, you’re going to require an inverter – we’ll cover what those are a bit further down in the guide. All houses use AC power to energize your appliances and other electronic accessories. When you plug your toaster into the wall at home you’re drawing AC power to heat up the elements. All modern homes are connected to the main power grid to use AC power.
DC Power
Direct current (DC) is a unidirectional flow of electric charge. A battery is a good example of a DC power supply. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC).
Still want to know more? Here’s a link to wikipedia.
DC power is the primary type of current you’ll be working with when setting up your solar system. From our experience, we’d also suggest using DC power for as many items in your system as you can.
Why should I use DC powered appliances in my camper van or RV?
The main reason is because your battery bank is already putting out power in a DC current. When we convert our DC powered battery to AC using an inverter we actually lose a bit of power in the conversion which makes AC appliances and electrical items a little less efficient to run.
It is highly advised to use electric accessories for your van or RV that are DC powered. Having the option to use AC power in your home on wheels is great but relying on AC power will drain your system more quickly. You can find almost every appliance and device for your RV that can run on DC including your fridge, lights, fans, and even your furnace. Even your phone is a DC powered device and that little brick you use to plug it into the wall actually converts the AC power from your home power socket to DC to charge the phone. It’s easy enough to install a few marine style USB ports in the wall of your van or rv and you’ll never need the little power brick again.
Breakers & Fuses
Breakers
An automatic device for stopping the flow of current in an electric circuit as a safety measure.
Still want to know more? Here’s a link to wikipedia.
These are very important to any electrical setup as they can stop overloads in your system from happening. Different breakers come with different strengths depending on how much electricity you want to flow through a specific connection. These breakers are set up in between a connection between two points where electricity will flow and can “break” to impede the flow of electricity if the current is overloaded.
In our van, we used breakers instead of fuses for our solar installation. We made this decision because we’re not always close to a store where we can buy new fuses. If our system ever overloads then the breaker will pop and disconnect the electrical current. All we have to do is check to see where our issue is, fix it and then re-engage the breaker.
Fuses
Similar to breakers a fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit. Its essential component is a metal wire or strip that melts or breaks when too much current flows through it, thereby interrupting the current. It is a sacrificial device; once a fuse has operated it is an open circuit, and it must be replaced or rewired, depending on the type.
Still want to know more? Here’s a link to wikipedia.
Just like breakers, these come in different strengths to allow systems to safely stop without causing a fire or a major system overload. Fuses get placed in the same areas that breakers are connected in a circuit. Unlike breakers, fuses actually destroy themselves to protect the system. If a current becomes large and your system is overloading the fuse will break and halt the electricity from flowing through the connection. We find the only downfall to having fuses is that they’re not always available so you have to be sure to keep a supply of them with you on your travels. Fuses used to be used in home electrical setups as well, but we now use breakers because they are easier to reset and don’t require you to purchase new ones every time the power overloads.
Using fuses or breakers are important safety measures that you have to think about while creating your solar power setup.
Wiring Sizes
Similar to breakers a fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit. Wiring comes in many sizes and types. To properly determine if the wire you’re using is safe, you should make sure your wire size is able to handle the amount of amps you will be placing through it. The main way to determine wire sizes and their ratings is to use the American Wire Gauge system (AWG). Most wires you purchase from the store will have a rating on them depending on their size. Its essential component is a metal wire or strip that melts or breaks when too much current flows through it, thereby interrupting the current. It is a sacrificial device; once a fuse has operated it is an open circuit, and it must be replaced or rewired, depending on the type.
Here are some common sizes for wiring and how many amps they can usually handle:
- 14-gauge wire: 15 amps
- 12-gauge wire: 20 amps
- 10-gauge wire: 30 amps
- 8-gauge wire: 40 amps
- 6-gauge wire: 55 amps
- 4-gauge wire: 70 amps
- 3-gauge wire: 85 amps
- 2-gauge wire: 95 amps
To learn more about wiring sizes check out this great article.
Solar Panels
Solar panels are made of an array of photovoltaic solar cells. These cells are wired together to create a desired watt rating for the panel. Generally you buy your solar panel already assembled but for those people out there that are a bit more adventurous, you can build your own solar panels from scratch. Unless you’re quite clever with a soldering iron, we’d highly recommend buying pre-built solar panels.
Types of Solar Panels
Monocrystalline
These are the most commonly used solar panels and they are made of monocrystalline silicon. Monocrystalline panels generally have a high-efficiency rate, they are less sensitive to high temperatures and they last a long time.
Polycrystalline
Polycrystalline solar panels are easily distinguished by their random triangular looking patterns in the panel. These panels are created by melting raw silicon and are generally less expensive and not as efficient as a monocrystalline panel. Polycrystalline panels can also be more sensitive to higher temperatures and they’re often not that efficient at producing electricity.
There are also Thin-Film Amorphous Silicon & Concentrated PV Cell Solar Panels but these won’t really apply to creating a good solar power system for your van or RV.
Which solar panels should I choose?
This question is a difficult one to give a straight answer to. The type of solar panels you choose will depend on your budget, how much power you need, and the amount of surface you have available to mount the solar panels. For most general purposes people will choose monocrystalline panels.
Hard Solar Panels or Flexible Solar Panels?
A hard solar panel will require a bit more effort to ensure they are stable and well secured to your vehicle’s roof but these panels are strong and can handle the most ware and tare. Going with a flexible panel can be a great option if you have an uneven roof but from our research, we’ve found that these panels can start to warp over time and the surface can be easily scratched if you’re driving into places with low hanging trees or objects.
A hard solar panel will require a bit more effort to ensure they are stable and well secured to your vehicle’s roof but these panels are strong and can handle the most ware and tare. Going with a flexible panel can be a great option if you have an uneven roof but from our research, we’ve found that these panels can start to warp over time and the surface can be easily scratched if you’re driving into places with low hanging trees or objects.
Solar Mounting Brackets
There’s not much here to explain! Mounting brackets are used to attach your solar panels to the top of your RV or van. The way you mount your solar panels will depend on what type of panels you choose and if you want to build or use an existing roof rack to attach your panels. There are many ways to mount your solar panels; some folks use mounting brackets that will allow you to angle the panels toward the sun and others will just mount their panels flat on the roof. Mounting your panels flat will be the least amount of work but will be the least efficient way to mount your panels. A panel that is tipped and pointing directly at the sun all day will net you the most electricity from your solar panels.
Batteries
There are so many types of batteries out there it’s hard to know what will work best for you. Buying batteries is one of the most important decisions you need to make when setting up your solar power system. Your batteries store all of the electricity that your solar panels collect during the day. Ideally you want to be able to use your electrical devices and appliances during the day and still be able to charge your batteries so everything still works when the sun goes down. This will require you to have enough panels to collect light but also enough battery power to run everything.
Lithium Ion
Pros:
- Longer lifespan
- Up to 80% safe discharge
- Faster charge times
Cons:
- Very expensive
Lead Acid
Pros:
- Cheap up-front cost
Cons:
- Short life
- Require regular maintenance
- Should only be discharged to 50%
- Have to be vented
- Need to sit upright at all times
- Longer re-charge time compared to Lithium Ion
Absorbent Glass Mat (AGM)
Pros:
- Can be placed on their side
- Don’t require ventilation
Cons:
- Shorter life
- Should only be discharged to 50%
- Longer re-charge time compared to Lithium Ion
What is an amp hour?
An ampere hour or amp hour (symbol Ah; also denoted A⋅h or A h) is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3600 coulombs.
Still want to know more? Here’s a link to wikipedia.
Essentially, it’s a way to give us an idea of how long a battery will last based on a 1 amp discharge of your battery over time.
For Example:
We want to run some LED lights that are rated at 1 amp.
If your battery has a capacity of 100 amp hours then theoretically, your lights will stay on for 100 hours. This calculation isn’t 100% accurate and will change depending on the type of batteries you use and the current temperature of your batteries. Weather can dramatically change how your batteries operate and should be taken into consideration when choosing the right batteries for your system.
Inverters
In order to convert your battery’s DC power to AC power you’re going to need an inverter. Any devices or appliances you have that require a standard wall plug will need a higher voltage of electricity to operate. Inverters take a standard 12 volt DC current and can convert it to usable 120 volt AC current. Be warned that converting power from DC or AC or back the other way can result in some power being lost and most of the time results in having your batteries drain faster. We feel like you should plan to use AC power as little as possible when planning a solar power system.
If you’re going to be using your solar power to charge your sensitive electronics like laptops and cameras then your only option for clean power is a pure sine wave inverter.
Types of Inverters
Pure Sine Wave Inverter
Pros:
- Very clean power free from other electrical interference
- Works well powering all electrical devices
Cons:
- Generally a little more expensive
Modified Sine Wave Inverter
Pros:
- Generally a cheaper device
- Works well for a lot of general electrical items like tools
Cons:
- Not safe for more sensitive electronics like laptops and CPAP machines
Charge Controllers
This device can be seen as a brain for your solar panels that protect your batteries and charge them correctly. Buying a cheap charge controller isn’t a good idea so spending a bit more money to get a decent charge controller is a wise investment.
The most efficient is the MPPT charge controller as it charges your batteries in stages and it will help you get the longest life out of your battery bank investment.
What does a solar charge controller do?
A solar charge controller limits the flow of electrical energy from your solar panel to your batteries in order to charge them safely and efficiently. Without a solar charge controller, solar panels would be connected directly to your batteries and this could cause serious risks to your safety. If you do not connect a solar charge controller between your solar panels and your batteries you may overload your system and cause fires or your batteries can explode.
Charging your battery bank from your alternator – is it worth it?
Having your house battery bank connected to the alternator in your engine is helpful if you move around fairly often. If you’re planning on staying in one spot for longer periods of time then this wouldn’t be a very effective option for you. It’s also a bit of a daunting task to connect if you have a more modern vehicle, so unless you’re really into digging into electrical manuals and consulting electrical charts we’d say leave this to a pro.
Our van already had the wiring in place to charge our house battery from the alternator. This was the only way to charge your house batteries in the 80’s before solar panels (our van is a 1984 Dodge B250). We decided to upgrade the wiring and add a kill switch so we can disconnect the alternator’s power from the solar charge controller.
We find with our alternator we can fully charge our batteries on cloudy days if we take a long drive. This also required us to purchase a special charge controller that allowed us to have our panels and our alternator to tie into the same system.
Calculating Power Needs
How much power will my items draw?
To do this you need to add up how many watts each of your electric items will draw on the battery and determine how many hours per day you will have to power each item. There are a ton of great solar power need calculators on the web to help you figure out your final number.
Will solar power be useful for me?
Before you start buying all of the pieces for your solar power system you should ask yourself if the amount of electricity you require is worth the price you spend on buying all of the elements you need to put your solar power system together. Your battery bank is where you’re going to spend the most money in the entire setup.
Here’s a helpful list of questions you can ask yourself to see if solar power is right for your situation:
What’s your budget for electricity?
Depending on what your budget is and how much electricity you plan on consuming, you should weigh over all costs of going solar vs buying a generator. Going green and off the grid is great but for a lot of situations, buying a generator and gas will be cheaper. Solar is a large one time expense while a generator costs far less upfront but has recurring gas expenses.
Are you spending a lot of time remote camping?
You’ll have to determine what type of camping you do most. If you’re going to be boondocking (dry camping) in the middle of nowhere often, having solar power can be quite helpful. Running a generator also works and will provide you with more power, but you have to think about noise & gas as well.
Are you a city dweller?
Running a generator in the city isn’t an option if you want to do some stealth camping. In this situation, you should look into building a solar system that will provide you with the power you need to get through the night.
Will you be spending most of your time at paid campgrounds or RV parks?
If you’re spending most of your time at paid campgrounds or RV parks, they generally have electrical hook ups so having a solar system probably isn’t necessary.
Are you staying in areas that you can’t run a generator?
If you are, solar is your only option.
Are you concerned about your carbon footprint?
Using a solar system can cut down on the amount of times you need to plug into the main electrical grid which, in the long run, will be better for the environment. It’s also a far healthier choice than using a gas-run generator.
Do you want to run air conditioning?
This isn’t impossible but you’re going to have to spend a fortune in panels and batteries to handle the load an air conditioning unit will put on your battery bank. Most vans and RVs simply don’t have enough space for the amount of solar panels and batteries you’re going to need to keep your air conditioner running. If you’re dead set on having air conditioning, you’ll probably want to look into staying at places with dedicated electrical hook ups or buy a generator.
Do you have more questions?
Ready to get started building your solar system?
Listed below are all the items we used to build our camper van solar system. If you want some more in-depth information about our van build (and wiring diagrams!) you can read our Complete Van Life Solar System article.
This information can be applied to any sort of solar power system that can be installed in any application that requires electricity. However, when creating a solar system for situations where your dwelling is hooked up to your region’s main power grid there are other considerations, like stopping your solar system from improperly discharging into the grid. You would also need to do plenty of research about the rules and regulations of installing solar power on your residence. We won’t be covering any aspects of residential solar power in this guide and we’d highly recommend you get in contact with your local solar power provider before setting up solar on your permanent residence.
Thank you for taking the time to read our helpful guide! We hope it’s been a great resource for you. If you have any questions, feel free to reach out to us on our contact form or Facebook.
*DISCLAIMER: WE ARE NOT PROFESSIONALS. ALL INFORMATION IN THIS GUIDE IS BASED OFF OF OUR OWN RESEARCH. WE HIGHLY RECOMMEND THAT YOU CONSULT A PROFESSIONAL BEFORE EXPERIMENTING WITH ANY ELECTRICAL SYSTEMS*
Very good information to use in your set up. You can see each item and learn all about them.
Glad you found it helpful Ron!