How Long Does It Take to Charge 12V Battery with 100W Solar Panel? -
Skip to content
Cart (0 item)

Your cart is empty

How Long Does It Take to Charge a 12V Battery with a 100W Solar Panel? – Understanding Solar Power for RVs

How Long Does It Take to Charge a 12V Battery with a 100W Solar Panel

Short on Time? Here’s The Article Summary

The article discusses the advancements in solar technology, particularly for RVs, and how solar panels are now more efficient and portable. It explains the working principle of RV solar power systems, highlighting their benefits such as cost-effectiveness, independence from grid power, environmental friendliness, quiet operation, low maintenance, and extending the life of RV batteries.

It also addresses the practicality of RV solar power systems and the considerations for determining the number of solar panels needed based on power usage. The article then explains how to calculate the time it takes to charge a 12V battery with a 100W solar panel, considering factors like sunlight exposure and the efficiency of the charge controller. It concludes by recommending affordable solar equipment for RVs and encourages readers to embrace solar power for a more liberating RV experience.


How Long Does It Take to Charge a 12V Battery with a 100W Solar Panel? – Understanding Solar Power for RVs

Given that solar technology is constantly evolving and becoming more advanced, it is no surprise that solar panels and other pieces of solar equipment are becoming more efficient and portable than ever before. In fact, solar is currently the world’s fastest growing energy sector, which partially explains why there has been so much innovation in the solar industry over the last decade.

All of this advancement is great news for RV enthusiasts, van campers, and other groups that are looking for reliable, practical, and affordable sources of portable power. Where solar panels and solar batteries were once bulky, inefficient, and extremely expensive, advances in photovoltaic technology, as well as solar storage innovations, have led to foldable solar panels and compact deep cycle batteries that can be taken anywhere imaginable.

To help you understand your options, we are going to go over everything you need to know about solar power for RVs. We will also answer some of the most common questions we are asked, like how long it takes to charge a 12 volt battery with a single 100 watt solar panel. We will also recommend products you can use to build your own portable solar power system.

How do Solar Power Systems Work for RVs?

RV solar power systems work just like residential and commercial systems; however, the components are usually more compact and lightweight. Just like any other solar power system, the solar panels in an RV system absorb sunlight, which creates electric current. The resulting electricity is direct current, or DC power, which is why most systems will use a power inverter to transform the DC power into more useable AC power. Since most of the appliances and electronics in your RV run off of AC power, a power inverter is a useful and practical piece of equipment.

Once the power has been converted to AC power, it will flow into a solar charge controller, which is a device that helps regulate the flow of electricity and protect your battery by preventing overcharging issues. From there, the electricity will charge your battery, so you can use it at your convenience to power everything from the appliances inside your RVs kitchenette, to your actual RV battery. 

So, Are RV Solar Power System’s Practical?

Many people assume that solar panels are just an expensive luxury for RV owners that have plenty of disposable income. The truth is RV solar panels are now more portable and affordable than ever before.

While it is not completely necessary that you purchase a portable solar power system for your RV, they do offer some really valuable benefits. It is also important to remember that a RV solar power system does not need to generate enough electricity to satisfy all of your power needs. You can almost think of a solar power system for your RV as a reliable source of backup power. Many RV owners that travel with portable solar power systems still use shore power when it is available, but they use solar power to give them the option of going off-grid, for a source of emergency power, to cut down on gasoline generator use, and to extend the lifespan of their RV battery.

If you are on the fence about a solar power system for your RV, consider the following benefits: 

  • Solar equipment is affordable and offers a cost-effective means of power. Most solar panels can generate enough electricity to pay for themselves in as little as 6 years. Given that they are designed to last for over 20 years, they are actually a wise investment.
  • Solar power can be accessed from any location, which means you would no longer have to rely on shore power hookups at designated RV campsites to access electricity. Having the ability to go off-grid allows RV owners to go on adventures that would otherwise be inaccessible.
  • Solar power is a clean and renewable source of electricity that helps you cut down on your carbon footprint. If you enjoy RVing, you are most likely someone that cares for the great outdoors. Since solar power is an environmentally-friendly power source, using it allows you to protect the natural world while you are enjoying its beauty.
  • RV solar power systems are extremely quiet and do not create any unwanted emissions. Unlike traditional generators, which burn gasoline, solar power systems produce no waste or unpleasant smells.
  • RV solar power systems require very little maintenance. The lack of moving parts means they can last for decades without needing much more than the occasional cleaning.
  • RV solar panels can extend the life of your RV battery. Relying on your RV battery to power all of your electronics and appliances puts a significant strain on it. Using solar power to charge your battery, or to take some of the burden off of it, usually extends the life of a RV battery by over 50%.

How Many Solar Panels Do You Need for Your RV?

If the benefits of an RV solar power system are appealing to you, you might be wondering how many solar panels you will actually need. As you would expect, the answer depends on the size of your RV and how much electricity you use.

Whether or not you run power-draining electronics, like a portable air conditioning unit, will determine how much power you need to generate. One of the easiest ways to come up with your specific solar power needs is to simply measure how much power you actually use.

We recommend taking a look at our Off-Grid Solar Watt Hour Calculator, which will help you size up your solar power needs. If you are planning on using solar power, it is also worth taking a look at your power usage and determining if you can reduce it in any ways. You can make a big difference by replacing old appliances with more energy-efficient models and by making small adjustments, like parking in the shade to keep your RV interior cool, rather than running fans and an air conditioner.

Once you have your power needs, you can then start looking at how many solar panels you will need to generate the specific amount of electricity you require. The next question you will want to ask is how long it will take for your solar panels to meet those energy needs.

How Long Does It Take to Charge a 12V Battery with a 100 watt Solar Panel?

Determining a specific amount of time to charge a 12V battery with a 100 watt solar panel can be tricky. For starters, the amount of direct sunlight your solar panel is exposed to will impact its efficiency. Next, the quality and efficiency of the charge controller you are using will have an impact on the time it takes to charge the battery.

Most charge controllers have an efficiency rating of about 85%, which means with direct sunlight, your 100 watt solar panel would have an adjusted power output of about 85 watts. If we assume the charge controller’s output is 12V, the charge controllers output current would be 85W/12V, which would equal about 7.08A. So, to charge a 100Ah 12V battery, it would take 100Ah/7.08A, which equals about 14 hours.

While this may sound like a long time, it is important to remember that this is just a single solar panel and it assumes that the battery you are charging has been fully discharged. In most cases, you would use more than one solar panel and your battery would not be fully drained to start out. 

The main thing is setting up your solar panels in the best location possible and having them charge your batteries often, so they do not become fully drained.

Affordable Solar Equipment:

Solar panels are also surprisingly affordable, so setting up multiple panels is a realistic prospect. Take, for example, our affordable 100 Watt Solar Panel. You can also purchase multiple solar batteries, rather than always relying on your RV battery. With a series of charged solar batteries, you will always have a reliable source of electricity, even on days when the sun is not shining. We carry a wide selection of high-quality Deep Cycle Solar Batteries from some of the best brands in the industry. 

Small-scale solar chargers can also be a useful option for RV enthusiasts, as they provide reliable off-grid power that can be used to charge portable electronics, such as cell phones, GPS units, and more. Check out our Review of the Patriot Power Cell, where we explain possible uses for portable charger kits and go over some of the best options on the market today.

Solar generators are also useful pieces of equipment for RVing, as they act as all-in-one solar power stations. Whether you need to charge your RV battery, power portable electronics, run your RV appliances, or just want a reliable source of backup power, a solar generator can fulfill your needs.


The Jackery Explorer 1000 Portable Power Station and its smaller counterpart, the Jackery 500 are excellent options. However, we carry a wide selection of power generators, so you can find the unit that meets your exact needs. Shop our Solar Generator Kit Collection to find complete kits that come with everything you need to access reliable solar electricity from anywhere your next RV adventure takes you.

Final Words

Embracing solar power can give you a whole new sense of freedom the next time you hit the open road with your RV. Given that solar equipment is more affordable and efficient than ever before, you can get started with just a small investment.

As always, if you have any questions about solar power, feel free to reach out to us at any time!

The Ultimate Solar + Storage Blueprint (Mini Course)

Struggling to understand how solar + storage systems actually work? Looking to build or buy your own solar power system one day but not sure what you need? Just looking to learn more about solar, batteries and electricity?

Join 15,000+ solar enthusiasts breaking free from their energy dependence with this short step-by-step video course that will make you a solar + storage expert. Start your journey to energy independence today.

Learn More Now

Who is is the #1 digital platform that enables consumers & businesses to source and purchase complete solar + storage solutions direct, saving you thousands in time, energy and money! With over 40,000+ happy customers, we’re on a mission to make solar simple, transparent and affordable.

Article by

Cody Oehm

Cody is the Head of Marketing at Shop Solar, and joined the company in spring of 2022. 

He has an entrepreneurial background and has been in the ecommerce industry since 2015. With 4 businesses under his belt and a drive to make a bigger impact, he decided to team up with Shop Solar on their mission to make solar simple and affordable. You can browse best seller's here.

Previous article Solar Powered Generators: 2 Most Common Questions We Get, Answered [Generator Sizing Guide]

Leave a comment

Comments must be approved before appearing

* Required fields

Blog posts

Get a Complimentary Solar Proposal Today!

$150 Value - Free Offer (Limited Time Only!) No Strings Attached. Totally Free. Takes Less than 2 Minutes.

Get Started