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What Size of Solar Panel To Charge a Battery of 12V?

There is no better way to charge your batteries than trapping the accessible energy from the sun.

To calculate what is the exact size of the solar panel to charge a battery that you would require to charge your 12V battery, you must be aware of the below-mentioned info to calculate what size solar panel you require:

  1. Battery Voltage (V): For you to know what is your battery’s voltage. We’ve already taken a step ahead and entered 12 volts, but it is always up to you. The liberty has been provided to you. You can always change it if your battery has some other voltage.
  2. Battery Amp Hours (Ah): Do you know the battery’s capacity in amp hours? (If you only  are aware of its capacity in watt-hours, then  you require first to change watt hours to a relative amp hour)
  3. Battery Type: Next, know your battery is lead acid or lithium (LiFePO4).
  4. Battery Depth of Discharge (DoD): What is the exact level that your battery provides? 100% means fully discharged, and when it comes to 0%, it simply means that it is fully charged.
  5. Solar Charge Controller Type: The decision is whether to use a PWM or MPPT solar charge controller.
  6. Estimated Charge Time (when the sun is at its peak): How rapidly do you expect the solar panel to charge your battery when the sunlight is at its full strength?

Once you’ve noted all the above data, you can easily “Calculate Solar Panel Size” to estimate the desired size panel required to charge your 12V battery at the best speed.

What is the Required Size of Solar Panel to Charge A Battery of at Least 12V?

To maintain a battery, the relevant term that is used is also called trickle charging. It is when you charge a charged battery with an equal discharge rate to keep it fully loaded.

Here we will provide a chart to display the size of the solar panel you might require using 12V batteries. 

Key Terms to Know Before Getting Started

We are about to use various technical terms you may not be acquainted with in this article. Hence, we provide some key terms that will simplify your understanding of the matter.  

  • Amp-hours: Thai is nothing but the amperes of current the battery offers in an hour.
  • Amp rating: This is yet another term for amp hours, but at times it is also known as amperage and wattage.
  • Charge controller: It is a gadget that helps you control when the battery is charging; it works like an on/off switch.
  • Inverter: It is required to connect your solar panel and transmute unusable DC energy into usable AC energy for domestic purposes.
  • Solar system: The necessary gadgets to light your home with solar power include PV panels, connectors, inverters, batteries, etc.
  • Voltage (voltage rating): It informs you about the potential output of the solar panel.
  • Wattage: It is nothing but the ability to provide service by solar panels or batteries.

Now that you are already acquainted with the technical jargon let’s delve deeper into solar panel batteries. First, knowing why you need to install them and how to make an intelligent decision while choosing the appropriate system for your needs is essential.

Why Solar Panel Batteries Are a Must

When people start their journey with solar panels for the first time, they are confused as to why they would need a battery. Though this question is relevant, the answer to this is even more straightforward.

As you know, solar panels can produce electricity only when the sun is out. Hence, solar panels may not be able to produce enough electricity on a cloudy day or night to provide your home with sufficient power to perform the activities conducted every day.

That doesn’t imply that you can’t use solar panels at any time of the day. You can continue using solar panels according to your requirement. Still, you will require a solar panel battery to maintain the power flow even during the nifty time. The motive of a solar panel battery is to supply you with solar energy, irrespective of where the sun is. The solar panels store the sun’s energy to power all home appliances during the day, but the battery works as a backup and will kick in at night.

The primary purpose of a solar panel is to supply solar energy irrespective of the sun’s position. The solar panel can harness the sun’s energy during the day, but the battery will kick in at night.

Are Batteries Always Required?

Deep-cycle batteries are not an essential requirement for every solar panel. But here is a simple guide to understanding when batteries are used for charging solar panels:

When your solar panel system is attached to its grid, batteries are not a basic need for those situations, but they can easily be kept as a backup. On the contrary, battery systems are essential if the grid is not attached.

For instance, grid-connected solar-powered systems don’t require a battery or a backup. The grid connection helps you facilitate a setup like leading steam electricity during nighttime or when the sun is down.

Hence, it can be said that systems connected to the grid can still reap advantages from batteries. However, even though you might be using solar panels, your electricity flow will be terminated if there is a  power shortage or a load shedding in your area.

You can easily use a solar battery as a backup to ascertain that you still have electricity and that the power flow will not be terminated.

It can be said that your electricity supply will be there even if the grid is down.

Some solar batteries become required when using solar panels to charge RVs or other devices not connected to the grid. It’s entirely your decision to determine if you need batteries for your setup. At least, having read this article, the process of making this decision becomes easier for you.

About Deep Cycle Batteries

You need to understand what we refer to when we discuss solar panel batteries. This particular type of battery we are talking about is not a power toy or available in your storage closet.

Instead, solar panel batteries imply nothing but deep-cycle batteries. So if you see them, they may appear quite similar to car batteries, but they are different.

Car batteries supply energy in short bursts, whereas deep-cycle batteries are fabricated to supply energy continuously.

Multiple other varieties of deep-cycle batteries are available. The basic ones are as follows:

  • Flooded lead-acid
  • Lithium iron phosphate
  • Sealed lead-acid batteries

These profound cycle battery kinds have advantages, disadvantages, and ideal usage.

What Is Deep Cycle Battery Best?

When do you want to research which deep-cycle battery the ultimate choice is? Awareness of the varieties available won’t do you a favor if you are unaware of their differences.

It is often seen that lithium iron phosphate batteries work more efficiently and have a faster charge rate when compared to its other varieties. These two reasons make them the best option for a  deep cycle battery regarding its performance.

As lithium iron phosphate batteries are more efficient, that is the reason that they can be costly and beyond the affordable rate of many; there are certain drawbacks to that too.

Although lithium iron phosphate batteries are considered superior, as mentioned above, three deep cycle batteries are considered the ultimate option— many people prefer lead-acid batteries for their cost-effective rates.

You can decide which deep-cycle battery you require by looking at the battery capacity, durability, and cost. But, it is always recommended that you don’t sacrifice quality for money as the market is flooded with efficient batteries that are more affordable than other models.

What Is a Solar Charger Controller?

Suppose you have decided to use a battery system simultaneously and your solar panel setup; it’s not just the battery or the backup you might require in the first place. You probably might think that you will all require wires and cables to attach the battery to the solar panel, but you are missing out on the most crucial part: the solar charge controller.

The function of the battery charger controller is to moderate the battery’s power supply and prevent it from overcharging. It certainly would be helpful to regard the solar charge controller and an on/off switch that will terminate the battery charging once it gets charged. 

When You Should Use a Controller

A solar charger controller is often regarded as the most intelligent way of investment if likely the solar panel system you are using is more than 5 watts. Hence, it can be said that solar charger controllers are essentially perfect if you use flooded lead-acid batteries, which often leads to overcharging.

Though it is often seen that solar charger controllers raise the cost of your battery system, it is still something you should consider purchasing.

Using it, not only will the quality of your battery be amplified, but it also ensures safety from breaking or investing into another battery without any reason. It can help you from unnecessary expenses in the long run.

Yet, you must remember that it can be challenging to predict the overheat or overcharge state without being aware of the battery configuration.

Hence, even though the flooded lead-acid battery or a 5-watt system is handy, a solar charge controller is better to be kept as a backup.

What About a Power Inverter?

Along with the solar charger controller, you must also purchase an inverter. Hence, you will require an inverter if you are not using a battery-powered system.

“Why?” the question might arise. See, the answer is simple: even if the sun’s rays might be supplying you with energy, the energy that is supplied is not in a form usable for your basic electricity needs.

The inverter converts solar energy into usable electricity for domestic purposes. If you do not have an inverter, the solar panels may become useless and not beneficial.

A Closer Look at How Inverters Function

When the solar panel stores the sunlight and transforms it into solar energy, this process supplies DC energy. However, DC power is not regularly used to lighten your home and appliances. Instead, it can be said that this form of energy refers to AC energy.

DC energy is often supplied to the inverter, which is processed through a transformer. The inverter significantly “tricks” the transformer and makes it work like AC energy instead of DC. Learn more bout the differences between AC & DC Power by reading the article; AC vs. DC: A Comprehensive Guide.

It simplifies why the transformer essentially makes the DC power act as AC energy. As the energy passes through the inverter, learn more about solar inverter sizing, it comes to a form usable for your primary home devices and appliances. Thus, it is supplied for your personal use.

How Does Solar Panel Battery Charging Work?

Now that we know the prime objective and components of a solar panel battery system, let’s be aware and informed about the different ways of the battery charging processes. If you know better how your battery works, you can intelligently choose the best system according to your requirements.

The efficiency of your solar panel system depends on whether it is attached to the grid. To understand the process thoroughly, let’s dive deeper into the off-grid, on-grid, and battery-free appliances.

Off-Grid Setups

Off-grid setups are the kind of systems that require battery power to run. But, as mentioned above, off-grid systems often drain power if they are not adequately exposed to enough sunlight at night.

The charging process is initiated through the solar panel. As you know, solar panels incorporate technology that can store sunlight’s energy.

The inverter transforms solar energy into usable energy. At that moment, the inverter will supply the usable energy to the battery bank if drained and not appropriately charged.

On the other hand, if the battery bank is ultimately charged, the solar charger controller will not supply any more power; instead, it terminates the connection between the inverter and the battery bank.

Similarly, the inverter transmutes usable electricity to your house, RV, or all places your solar panels are attached. As a result, you can quickly and adequately utilize all your electronic devices.

As the sun sets, the solar panels lose their capacity to create more energy. But you can always use usable energy with the battery bank system.

The entire process goes in cycles at different battery charging stages, just as a “trickle charge” stage, to ensure the battery is ready to use and fully charged.

On-Grid Setups

On-grid setups are pretty similar in the way they work in storing energy through the battery. The prime difference being the utility grid and utility meter are both included.

If the battery is fully charged, you don’t have to worry anymore, and all usable electricity will be transmuted from the inverter to all the appliances, as before. The dissimilarity between off-grid and on-grid systems happens after energy has been discharged to the home.

The energy production of your house and its usage are tracked with the help of a utility meter. Net metering is always recommended because it allows you to get paid for excess energy produced and can be transferred back into the grid. In addition, it helps you generate your electricity bill if you’ve utilized grid energy more than solar energy.

The utility meter usually develops a connection with the utility grid. Therefore, due to this utility meter and utility grid, the houses attached to solar power will be disconnected from electricity in case of a power outage.

The battery can be used and switched on as a backup option whenever you face a power cut from the grid. This is why an extensive number of people who are attached to the grid still choose a deep-cycle battery.

What Size Solar Panel to Charge 12V 50Ah Battery?

  • You will require a 160-watt solar panel to charge a 12V 50Ah lithium battery to 100% deep discharge in 5 peak sun hours and an MPPT charge controller.
  • You only need 330 watts of solar panels to charge a 12V 50Ah lithium battery to 100% deep discharge in 5 peak sun hours, along with a PWM charge controller.

How Fast Can Solar Panels Charge Batteries

After getting yourself a perfectly sized solar panel, you must connect them to charge the batteries.

These are the following parts that you would require to charge the batteries:

  • Solar panel
  • Battery
  • Solar charger controller
  • Battery cables
  • A solar panel to charge controller adapter cables.

You need to connect the battery to the charge controller. All you need to do is plug the negative battery cable’s striped end into the charge controller’s negative battery terminal. Shut the terminal with the help of a screwdriver, and you are done. The process goes in cycles for positive battery cables also.

Consult your user manual if you are confused. Next, plug in the positive solar panel adapter cable to the positive solar panel cable. Again repeat the same process. 

The following steps involve you putting the solar panel outside in the sun. First, take the solar panel outside and face it towards the sun. Next, all you need is nothing but being a bit patient for the battery to be charged by the solar panel. The charge controller will terminate by itself once the charging is done.

How Many Amps Do I Need To Charge A 12 Volt Battery?

Simply speaking, it’s not the amps that are more vital. It is the amp hours that are more important. Amp powers provide information on how much power can be supplied per hour.

By dividing the watts by the voltage, you can quickly know the exact amps your panel produces.

For example, if you have a 12V solar panel with a wattage of 100. If everything is correct, the voltage will be around 18 volts. 

Hence, you can easily divide 100 watts by 18 volts. So the output will be around 5.5 amps per hour.

How Many Can Watt Solar Panels Check Deep Cycle Batteries?

To confirm how many panels you require to charge a 12-volt battery, you need to learn some calculations.

Step 1:

Start by looking for amp hours and voltage to know the watt-hours required. Then multiply the amp hours by the voltage. 

Step 2:

This step requires you to divide the watt-hours that you found in the above step by the approx amount of sunlight per hour.

The actual size of your solar panel will tell you how many batteries you need to keep your batteries fully charged. 

Remember that the solar panels should exceed slightly more than 420 watts. Solar panels often won’t produce energy at their maximum levels.

Hence, you can consider that getting exactly enough panels for 420 watts signifies that the wattage will be lower than your battery.

How to Set Up Your Solar Energy Station?

Setting up a solar panel battery station is easy and quick. All you need to do is attach the battery to the panel and set up the solar system as you usually do.

Attach the battery to the panel:

You started by attaching the solar panel to a regulator. Then you need to attach the regulator to the battery.

Most of the time, the user manual is provided, and you are guided on how to do it. But, in case you are confused, you can quickly get hold of any professional who can hook the system for you and give you advice.

Solar Panel Placement

You must place the solar panel in such a way that it gets maximum sunlight exposure to it. For example, most people keep it at a 45-degree angle, facing the sun on a flat surface. 

The rooftop is one of the best options because it has few obstructions. But, if your roof is not strong enough to hold the solar panel, you can decide to install it somewhere on the ground. Just be sure that there are no trees or any other obstructions.

Can A 100W Solar Panel Charge A 12v Battery?

Yes, it can. But certain factors need to be considered. For example, knowing the wattage alone will not do it all and provide accurate predictions. In other words, you must know about the amp hours and the exposure the system is getting from the sunlight to speculate the exact duration and procedure of charging.

Final Words

To conclude, you can say that solar power batteries are a requirement. It doesn’t matter if you choose lead-acid batterie or lithium batteries. However, it is already known that most people go for lead-acid batteries.

Though they are a requirement for the grid, the systems attached to the grid can benefit themselves.

Though finding the perfect system to fit your battery can be strenuous. But if you have decided to invest in all of your efforts to set up your battery system, you have the liberty to choose solar generators as an alternative.

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