What size of solar panel to charge a 12v battery is useful in 2023? (2023)

My home is in an area without electricity which is the main reason I am turning to a better energy source that will give me 24/7 power and save me huge utility bills. That's why I installed off-grid solar panels on the roof of my holiday home. Panels kept me powered as long as the sunlight was absorbed.

By using a solar panel to charge a 12V battery, you can avoid relying on fossil fuels and reduce your dependency on the grid, which can be particularly useful during power outages or emergencies.

The panels only provided sufficient power to run devices during daylight hours, but could not power devices at night as the system shuts down at night. And then, after exploring the solution, I came across the option of setting up batteries along with panels for installationOff-Grid-Systemfor additional power storage. The fact is that panels and batteries are interdependent and are ineffective without each other.

A crucial question arises here: What panel size is required to charge a battery? In this article, I looked at a 12V inverter as an example. As you dive into the article, I can answer all your questions and help you set up a solar panel system to charge a 12V battery.

Table of contents

Reasons to choose solar energy to power batteries

What size of solar panel to charge a 12v battery is useful in 2023? (1)Solar energy is a renewable and inexhaustible source of energy, and modules rely on the sun's energy to generate electricity. And to store the electricity, you need solar panels.

By using solar panels, green and pocket-friendly electricity can be obtained, reducing the burden on a household. The environment is not harmed, resulting in a sustainable and green living space.

An added benefit here is that solar energy provides mains grid offload. Solar panels have been lighting my house for a while now.


There are better options than using regular batteries for a panel as these batteries provide short bursts of electricity to start a device. Deep cycle batteries are designed to produce a constant supply of energy. These batteries are used as a memory bank to provide power for connecting devices such as lamps,TV,Refrigerator,alternating currentetc. What sets deep cycle batteries apart is their ability to withstand far more charge and discharge cycles.

In general, there are two types of deep cycle batteries: Flooded lead-acid cells have an efficiency of around 70% to 85% when sealedlead-acid batterieshave 80%-90%. Choosing a quality deep cycle solar battery is important to store solar power and meet power needs.


Size of solar panel to charge 12V battery:-

Aspects to analyze when choosing panel size

Panels in demand are available in four sizes:
36 cells,
60 cells,
72 cells and
96 cells.

Commonly, 60-cell and 72-cell modules are used for household use.

Regardless of my considerations, many other factors also contribute to choosing a sensible panel. I have listed all the factors that need to be considered. Let's go through the aspects one by one.

1. Tension

Voltage is the difference in electrical potential between two points that allows electrical current to pass through the wire.

To fully charge a 12V battery, consider a panel that can deliver around 12.6V to 13.6V.

2. Wattage

The rate at which energy is dissipated is referred to as watts/wattage. The higher the wattage of the panel, the faster the charging speed.

Let me illustrate my point with an example -

A 50W panel will charge a 12V battery in 8 hours, while a 20W panel will take almost 15 hours to achieve the same.

Remember to charge the battery properly, otherwise permanent damage may result.

An ideal high-efficiency 36-cell panel delivers 180W. Larger panels are suitable for larger batteries.

3. The ampere-hour

Amp-hours are a key factor to consider when purchasing an adequate battery for variable size panels. Amp-hours refer to the amount of amps that a battery can deliver in one hour. A 12V battery with 100Ah can supply 100 amps of electricity in one hour.

To charge a 12V 100Ah lead-acid battery, a 220W solar panel with an MPPT charge controller and 5 hours of sunlight exposure. To charge a 12V 100Ah with a PWM charge controller, a 270W panel is required.

Steps to charge a 12v battery with a panel

Charging a 12V battery directly from panels is impractical due to the lack of compatible connectors and sockets in solar panels. Therefore, setting up a direct connection is a dangerous and unacceptable option. In addition, due to the fluctuations in solar energy, there is a risk of overcharging and eruptions after direct contact.

A key to this lock is-Solar charging rules, a gadget that acts as a safety controller and automatically turns off the power pool once the battery is finally charged.

What size of solar panel to charge a 12v battery is useful in 2023? (2)

Charge controllers are devices that convert the voltage from solar panels to a more reasonable voltage for the battery. Now let's jump straight to the steps for charging a 12V battery.

  1. Buying a suitable charge controller is the first and most important step. When purchasing, you will come across two types of controllers:MPPT (Maximaler PowerPoint-Tracker)AndPWM (Pulsweitenmodulation). The former is more efficient and takes 30% more energy to store, but is expensive.
  2. The next step is to install a charge controller. The controller should be installed in a dry, secure, and non-metallic location to avoid damage from the elements. Direct contact with the ground is preferred.
  3. The 12V battery should be equipped with wires. Also, connect the wires to a charge controller and secure the connection. Now connect the controller to the panel.
  4. Once all connections are secured, turn on the power system and panel.

When everything is ready, set the battery to charge. The charge controller updates the charge time by lowering the voltage output and stability to zero when fully charged.

Frequently asked Questions:-

  • What are deep cycle batteries?

Batteries as energy storage for connecting multiple devices are specially designed to quickly regulate the charging and discharging of solar power.

  • How long do panels take to charge a 12v battery?

Charging a fully discharged battery takes at least 5-8 hours. But again, many other factors affect charging performance, including the sun.

  • Is there an alternative to solar battery systems?

Solar power generators are easy to use and comfortable devices. An additional advantage of generators is that all the necessary parts such as battery and charge controller are included and you do not have to buy each part separately.

  • What Are the Uses of Deep Cycle Batteries?

Solar batteries for off-grid energy storage systems. Vehicles include RVs, wheelchairs, marine trolling gear, navigation equipment, etc.

last words

Sometimes it creates confusion about whether charging the battery is okay or switching to solar generators.

But an important fact to consider here is the appropriate size/number of panels that will charge a 12V battery properly, as the size and number of panels will vary depending on the location, weather where you live and the battery you use may vary.

I have mentioned all the simple steps. So before you get confused with all these methods, try to find out the type of power source before installation.

But yes, you can easily switch to battery charging options with the above steps. I prefer installing on-grid solar panels or saving my money to buy a generator which is more convenient for me and I hope it will work for you too.

What size of solar panel to charge a 12v battery is useful in 2023? (3)

ray garcia

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Ray is an avid reader and writer with over 25 years of experience serving various domestic and multinational private and public energy companies in the United States.

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