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How Long Does It Take A 200W Solar Panel to Charge A 12V Battery?

How Long Does It Take A 200W Solar Panel to Charge A 12V Battery

Short on Time? Here’s The Article Summary

The article explains the charging time of a 12-volt battery using a 200-watt solar panel. It states that a 200-watt solar panel generating 1 amp of current takes between 5 to 8 hours to completely charge a 12-volt car battery. Factors affecting charging time include the quality of solar panels, efficiency of the charge controller, state of the battery, and sunlight absorption. The article also discusses the different stages of battery charging and provides a formula to calculate current produced by solar panels in amps.

It emphasizes the importance of using deep cycle batteries for solar power systems due to their ability to handle repeated charging and discharging. The article concludes by explaining how to connect batteries to a charge controller and inverter for optimal energy usage.


If you are reading this then you might be planning on running an off-grid solar power system with 200-watt solar panels. Or, you might just want your energy needs to be met while camping.

It’s useful to you to know how long it takes a 200-watt monocrystalline solar panel to charge a 12-volt battery for planning.

If you would like to understand a bit more about charging time for a 12-volt battery with 200-watts solar panels, take a read.

How Long Will It Take to Charge a 12-Volt Deep Cycle Solar Battery?

How Long Does It Take A 200W Solar Panel to Charge A 12V Battery

The short answer is that a 200-watt solar panel that generates 1 amp of current takes between 5 to 8 hours to completely charge a 12-volt car battery. However, it is a bit more complicated than that.

The charging time depends on numerous factors. Factors include the quality of solar panels that are being used, the efficiency of the charge controller, the state of the battery, the amount of sunlight that is being absorbed by the solar panels, and more.

With that being said, if your battery’s amp hour rating matches the amps being produced by the solar panels, then the charging time will most likely be between 5 and 8 hours.

And if you want to ensure that the charge is an effect, have your solar installation orientated to directly face the sun, with no obstacles in front of it. You can expect the charge cycles to be slower on cloudy days and quicker on sunnier days. 

To give a more detailed explanation of how long it takes to charge a deep cycle battery, we have laid out the different charging stages.

Charging Stages

Bulk Stage

In the first stage, the maximum voltage is identified and passed on to the battery. The charge controller keeps the voltage at a consistent level. When the bulk stage is completed, then the voltage decreases.

Absorption Stage

As the voltage levels lower, the battery’s internal resistance increases. Once the battery has reached its full storage capacity, the battery’s internal resistance will be at its peak.

Float Stage

At this stage, the battery is just about charged. This is where maintenance becomes relevant.

The charge controller will allow enough electricity to pass into the battery to stay fully charged.

Through a natural discharge, this stage prevents the battery from losing its stored energy.

How To Calculate A Deep Cycle Battery’s Charging Time

The total charging time will depend mostly on the battery’s capacity and the power rating of the energy resources being used to charge the battery. Meaning, you need to know the following factors: the amperage, the voltage, and the wattage.

What Is Wattage?

A solar panel’s wattage indicates the solar panel’s power production under ideal conditions, such as sunlight and warm temperatures. You can read more about 200w solar panel output per day.

Theoretically, a 200-watt solar panel should have a power output of 200 watts. As discussed below, it is not as simple as that.

What Is Voltage?

In short, voltage equals the pressure that pushes the current.

Voltage indicates the amount of electrical potential that your battery holds. Voltage is expressed in volts (V).

What Are Amp Hours (Ah)?

An essential concept to know is amp-hours. Amp-hour is a form of classification that is used to describe the amperage that can be supplied in one hour by a given battery.

Deep cycle batteries explain their amp-hour classification in the form of an Ah number. If you know what the Ah rating of your 12V battery is, then you can work out the amp rating for your 200-watt solar panels. If you know your amp rating, then you can figure out how long it will take to charge your 12V battery.

To get a detailed explanation about amps, read 200-watt solar panel amperage.

The Formula

To compute the current that is being produced by your solar panels in amps, do the following formula:

Amps (Ah) = Power (Watts) / Voltage (V)

In essence, you divide the power by the voltage to get the amp rating.

For example, if your deep cycle battery has a capacity rating of 100 amp hours and your charger has a power output of 10 amps per hour, it would take 10 hours to fully charge the battery.

What is a 12 Volt Battery?

How long it takes a 200W solar panel to charge a 12v battery

After buying solar panels, the next move is to obtain batteries. Batteries will store all the solar energy utilized by the solar panels. Consequently, there will be power backup even if there is a blackout should your solar system be part of a grid.

When you use 12V batteries as part of your solar power installation, you can store the excess energy your panels produce instead of returning the energy to the grid. Electricity gets sent to the grid if your batteries are charged and your panels will still produce energy.

A battery also requires a solar charge controller and inverter.

A charge controller is a solar-powered voltage and current regulator. It regulates power input to deliver the best power output to charge batteries.

An inverter transforms direct current electricity, generated by a solar panel, to alternate current electricity, which is then used by an electrical grid.

When we refer to 12-volt batteries, many will think about automotive car batteries. For example, you can have a 12V battery for an RV. Also, check out “Is 200 watt solar enough for an RV?”

For solar power, however, these 12V batteries are a bit different.

Before we delve into how long it takes a 200W solar panel to charge a 12V battery, it is worth discussing what deep cycle batteries are. 

Why Should I Use Deep Cycle Batteries For My Solar Power System?

Deep cycle batteries can provide a long, stable stream of energy compared to traditional car batteries.

Deep cycle batteries can be discharged and recharged regularly without being harmed as quickly as normal batteries. Meaning, these deep cycle solar batteries can handle repeated charging and recharging that take place at speedy rates.

For example, traditional car batteries are made to give a quick burst of power to start a vehicle’s engine. On the other hand, deep cycle batteries are designed to be used as power storage of sorts.

A deep cycle battery can be utilized to provide power to many electronic appliances and devices. For instance, televisions, lights, smartphones, and laptops. You can also find out if a 200-watt solar panel can run a refrigerator.

If you are planning on storing solar electricity to gratify your energy needs, you must select a good deep cycle solar battery.

You can charge an automotive battery with solar energy, but we would recommend that you use deep cycle batteries to run your devices and appliances.

How Do You Charge The 12V Batteries with 200W Solar Panels

To use the batteries as part of your solar system, you need the following: a 200-watt solar panel, a charge controller, and an inverter.

Firstly, you will need to connect the battery to a charge controller to monitor how much energy is being stored to prevent overcharging from occurring. If the batteries become depleted of energy, then the charge controllers will shut down the whole solar power system.

Secondly, before you can power your appliances, it is necessary to connect the inverter to transfer the energy that gets collected from the solar panels. It might be good to know what you can run off a 200-watt solar panel.

Lastly, be aware that your 200W solar panels may be functioning perfectly at all times. Ensure that you maximize the solar panels’ efficiency by placing them in a good direction and location.

Final Thoughts

When figuring out how long a 12v battery can charge with a 200w solar panel, you have to know basic terms such as ah, watt and voltage.

Now you know that a 200-watt solar panel can take between 5 to 8 hours to charge a 12-volt battery.

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Article by

Alex S

Alex is a co-founder of Shop Solar, a company that he established in 2018 to revolutionize the solar industry by simplifying the process and making it more simple and cost-effective. Under his strategic leadership, Shop Solar has grown into a comprehensive one-stop-shop, empowering over 40,000+ customers to access top-quality solar and storage solutions, comprehensive information, intuitive tools, and professional installation services.

With a passion for innovation and sustainable energy, Alex has successfully expanded the business's reach and impact, serving as a driving force in the company's growth and development. You can browse best seller's here.

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