Wednesday, May 15, 2024

Solar Panels That Charge Batteries

Can I Use A 24v Solar Panel To Charge A 12v Deep Cycle Battery

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Yes. You can use a 20V panel to power up a 12V battery. That being said, A 24V panel is better than a 12V solar panel for the job.

Just because you can use a 24V solar panel does not mean its the best option. Go through the calculations above to determine what size solar panel is best based on your energy usage and needs.

How To Calculate Solar Panel Battery Charge Time

Anyone who has dealt with solar power knows some math is involved. But the process is easy and you can apply these principles for any number of batteries. In this example we are using 12V 100ah batteries.

Solar panel watt output per hour x number of sun hours available = watt output per day

With this you can estimate how long your solar array will take to charge four batteries.

The number of solar panels needed depends on how quickly you need those batteries recharged. It also hinges on the battery depth discharge, whether it is fully discharged or at 50%.

Four batteries at 100ah and 12V is 4800 watts. A 300 watt solar array can produce 1500 watts a day with 5 sunlight hours available. You may try this with the Renogy Solar Panel Kit for example.

  • You need 4 x 300W solar panels to recharge four batteries in 5 hours.
  • If you only need those batteries every two days, you can recharge them over two days with 2 x 300W solar panels.
  • If the batteries are only 50% discharged. the charge time is reduced to half.

Four 12V 100ah batteries at 50% DOD is 2400 watts. With 4 x 300 watt solar panels the charge time will be 2 to 3 hours. A single 300 watt solar panel can recharge four 100ah batteries at 50% DOD in 2 days with at least 5 sun hours availability.

Solar Chargers For Batteries: 12volt Small Applications

A solar battery charger is a Portable solar charger for batteries will 1.5 watt and 5v to 100 watt 12volt output, produce power, converted from sunlight. Best Solar Battery Chargers& Charging Kit includes a solar panel charger, charge controller, inverter, Cigarette lighter socket and one pair crocodile clip used for car, boat, cell phone, RVs, tractors, ATVs and many small electronics. Solar panel converts sunlight to DC electricity and recharge the car battery.

Some small Solar chargers are a combination of solar module and a dual USB battery bank, the device is handy and compact and can be easily transported.

An internal battery of the solar charge battery bank is charged with the solar module, so a cell phone, smart watch, action cameras, MP3 players, e-readers or other small power consumed devices can be charged while traveling.

On a long tour through the middle of nature, even big power backup reach their limits.

Solar power chargers can also be attached on a backpack during a tour to recharge itself and generate power.

A Solar Chargers for Batteries is available in many different sizes that ensure easy transport.

When charging the solar cells, you must always pay attention to the optimum angle of the suns rays that coming without any shadow.

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What About A Power Inverter

In addition to the solar charger controller, you must get an inverter. So even if you do not opt for a battery-powered system, you still need an inverter.

Why? you might ask. Well, the answer is straightforward: even though the suns rays provide energy, the energy is not in a form usable for your homes electricity needs.

The role of the inverter is to turn the sunlight energy into usable electricity for your home use. Without the inverter, your solar panels are essentially useless.

A Closer Look at How Inverters Function

Whenever your solar panel traps the sunlight, the sort of energy produced is called DC energy. DC power is not a form of electricity used to power up your home and appliances that form of energy is called AC power or energy.

DC energy is sent to the inverter, where it runs through a transformer. The inverter essentially tricks the transformer into acting as though it is running AC energy instead of DC.

From this trickery, the transformer essentially forces the DC power to act as AC energy. Of course, the inverter doesnt actually trick the transformer, but the example suffices.

Once the energy goes through the inverter, it is now in a form usable for your home devices and appliances. Hence, it is sent to your home for use.

Dont Forget About Cables.

The last thing you need to get to use a solar battery is cables or connectors. These devices simply connect the battery to the inverter and overall solar systems.

How Do I Know If My Solar Panel Is Charging

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If you have a solar charge controller, it will show you how much electricity is being produced by the solar panel, as well as how much current is being put out.

If, however, you do not have a solar charge controller and your battery is directly connected to a solar panel, you will need to check if it is charging in an alternative way. As we talked about above, this is where you will need a digital multimeter to measure DC voltage using probes, one red, and one black.

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Different Types Of Solar Batteries

Learn which kind of battery is used for solar panels.

Lead Acid

For several years, lead-acid batteries have been used as a reliable energy supply for off-grid areas. They are typically deep-cycle and inexpensive. Lead-acid batteries are attributed to high power and discharge current but low energy. They take long to charge completely up to 14 hours.

These batteries must be disposed of correctly or they can be an issue to the environment due to their highly toxic nature.

Two types of lead-acid that are commonly used for solar panels: flooded and valve-regulated lead-acid batteries.

The flooded lead battery is a dependable option but requires watering and proper ventilation to function. The VRLA, which is equipped with valves for off-gassing regulation, comes as two types, gel and absorbed glass mat . These are suitable for cold and warm temperatures respectively. Although the VRLA batteries give enough flexibility for installation, their sensitivity to temperature may however pose a challenge to people looking for a permanent alternative to their grid supply.


Lithium-ion batteries have become a more popular choice for solar systems all over the world. The development of this type of battery has a lot to do with its application in the electric car industry. Its prismatic form allows for ventilation and benefits use in solar systems.

Nickel Cadmium
Sodium Nickel Chloride

Is There An Alternative To Solar Power Battery

If you find it difficult to do the math and best predict what solar panels to get with your 12 Volt battery, you might want an alternative instead.

Solar power generators are great alternatives because they are easy to use and convenient, especially for beginners.

Instead of buying all parts separately, the solar power generator comes with the battery, inverter, and solar controller. As a result, you dont have to buy all the parts separately, ensuring they go together perfectly.

You dont have to buy special solar panels when using a solar panel generator, either. The same panels that power your battery will power the generator.

There are some downsides to using a solar generator. First, the price is much higher since it is more convenient and you cant shop around for individual parts.

The high price and lack of customization are why many expert solar panel users opt for their own battery system. However, the convenience of generators may be ideal for beginners who are still trying to figure out the solar world.

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How Many Solar Panels Do I Need For A 12v Battery

To find out how many panels you need to charge a 12 Volt battery, you need to do some math. This math will be based on the factors described above.

Step 1:

Begin by finding the amp hours and voltage to find the watt-hours needed. Simply multiply the amp hours by the voltage. Heres an example:

12Vx210Ah=2520 watt-hours

Step 2:

Next, divide the watt-hours, which you found in step 1, by your estimated amount of sunlight in hours. Heres another example when 6 hours of sunlight is available:

2520/6= 420 watts

This number tells you that you need to get the right solar panels to produce over 420 watts. Then, get however many solar panels are needed to exceed this amount.

Solar panel size will likely affect how many you need to keep your solar batteries juiced up. For example, a large size solar panel will be better than a small panel.


Keep in mind you want the solar panels to exceed 420 slightly. Most of the time, your solar panels wont produce energy at their optimal levels.

For example, power can vary depending on sunlight and the number of charging cycles youve already done through.

As a result, getting exactly enough panels for 420 watts means that the wattage will be below what is needed for your battery.

How Much Time Will It Take To Charge Multiple Batteries With One Solar Panel

Over Charging battery backup with solar panels

Using a PWM charge controller, you can easily calculate charge time under ideal conditions. However, as you will see, you can decrease the charge time by using an MPPT charge controller.

MPPT charge controllers are more expensive than PWM charge controllers but significantly increase the efficiencies of the system.

Most deep-cycle solar batteries are lead-acid batteries. Further, when using a PWM charger, the voltage of the solar panel doesnt matter.

A PWM charge controller will drop the voltage to the voltage of the battery. So, for example, if you have a 12-volt battery, the voltage of your solar panel will be 12 volts, even if its higher.

Because PWM charge controllers cut voltage, they also force wattage losses.

The calculation for charge time is Time = Battery Capacity * 2 / Panel Power in Watts

For a 100-watt solar panel and a 12-volt 100-amp-hours battery, the charge time from a 50% discharge value is:

Time = 50 amp-hours * 2 / 100 watts = 1 hour

If you switch to an MPPT charge controller, the voltage of the solar panel isnt restricted by the battery system. Instead, the MPPT maximizes all electrical variables to deliver the most power possible across the system.

Using an MPPT charge controller will deliver more power with fewer losses.

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Solar Battery Charging Facts

The maximum output of the solar cell is 150ma. This is with the best conditions. A high capacity rechargeable Nimh can hold 2000mAH. This means that it would take hrs to fully charge it. This is about 13hrs!When choosing solar cell arrangements one needs to work outa) How many batteries do you want to charge at onceb) How fast do you want them to charge.By adding extra solar panels one can charge more batteries, charge batteries faster or even both at the same time.So how does this work?

V 50ah Lithium Battery

60 watts


  • You would need around 350 watts of solar panels to charge a 12V 120Ah lead acid battery from 50% depth of discharge in 5 peak sun hours with an MPPT charge controller.
  • You would need around 440 watts of solar panels to charge a 12V 120Ah lead acid battery from 50% depth of discharge in 5 peak sun hours with a PWM charge controller.

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Alternatives To Be Aware Of

Because charging up your deep cycle battery with a solar panel requires many parts, many new users prefer buying a starter kit instead.

Starter kits come with all the necessary parts, taking away the hassle of finding appropriate parts. Starter kits are not necessary if you dont want them, though.

Another alternative is solar power generators. Generators come with all the parts already included.

Much like the kits, many newbies like generators for their convenience and ease of use.

It is up to you to decide which system is best based on your skills, budget, and requirements.

What Is The State

Charging Boat Batteries with Solar Panels

The state-of-charge is how much charge is left within a single deep cycle battery or a solar battery bank. The state-of-charge voltage varies slightly depending on the type of deep cycle battery being used. This could be a sealed or flooded lead-acid battery, a gel battery, or an AGM battery, and it will further vary for different brands.

The age of the battery, along with weather or climate conditions, will also affect the SOC of a battery as they eventually cause a reduction in the full amount of charge a battery can hold. This is why it is essential to check the SOC regularly so you can ascertain the health of each deep cycle battery in your solar battery bank.

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How Long Does It Take To Charge A 12v Battery With A Solar Panel

Typically, a 100-watt panel produces around 6ah per hour under ideal conditions or roughly 30ah40ah per day. If youre charging a 100ah battery from a flat, it will take about two days to fully charge the battery.

Its important to note that proper battery maintenance and care requires that your 12v battery never goes under 50%.

This is usually maintained by a charge controller, so youll technically only need a panel that can produce 50ah per day to keep your battery fully charged.

Connect The 12v Battery To The Solar Charge Controller

Connecting a battery to a solar charge controller requires wires, wire connectors, and an inline fuse.

You can use your own wire and connectors, or you can buy some to make the process a little easier. I ended up buying something called the NOCO GC018. Its a 12V plug adapter that comes with an inline fuse and ring terminals the right kind for my 12V battery.

To start, I cut the 12V plug off the NOCO GC018 with my wire cutter.

Then I just pulled the wires apart a little bit and stripped the ends.

Now my wires are ready. I can connect them to the battery terminals using the ring terminals. And I can connect them to the charge controller terminals using a screwdriver.

So thats what I did:

I first connected the positive and negative wires to their respective battery terminals. Like so:

Then I used a screwdriver to connect the stripped wire ends to the charge controllers battery terminals. My controllers terminals have a battery icon on them, as well as a plus and minus, to help me know where each wire goes.

When all the wires were connected, my charge controller turned on to indicate that it was properly connected to the 12V battery.

Consult your charge controllers manual for instructions on how to program it for your battery type. Mine defaults to sealed lead acid batteries, which is the battery type I was using.

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How Is Big Of A Solar Panel Needed To Charge A Deep Cycle 12 Volt Battery

Charging a 12 volt deep cycle battery its essential to consider factors like design, features and the cycle system, means the makeup of the deep cycle battery including the size.

This battery is the standard battery often use in cars, RVs, troller boats, etc. this type of cell is designed to charge and recharged numerous times. They are rated according to amp hours.

That means how many amperes the battery can offer a fixed amount of time/hours. The most common battery in this category is 350 ah. This battery can deliver 35 amps of power over the set of 10 hrs of use.

The Correct Way Of Solar Panel Charging Car Battery

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If youre going for a DIY approach, ensure that your charging system has a charge regulator to control the voltage.

When using a solar charge regulator, you could attach one end of the controller to the battery. From there, you can attach the other end with your solar panel.

Such a method significantly aids in regulating the voltage so that your battery wont exceed the safety limit. The charge regulator tracks the voltage of the battery, a process known as pulse width modulation.

Using a charge regulator can help keep the battery from going beyond the target limit or the safe float voltage. Luckily, its safe to leave this type of setup attached continually without worrying about the potentiality of battery damage.

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Lithium Vs Lead Acid Batteries

Lead acid batteries have a 50% depth discharge rate. So if you have a 100ah lead acid battery, only 50ah should be used. Once the capacity reaches 50ah, it is time to charge. This can be frustrating if you run a lot of appliances on solar. It might also seem like you are not getting your moneys worth since you only get to use half the capacity.

With lithium batteries you can use up to 85% or more. Each charge lasts longer and you can use more, which is ideal for heavy duty applications.

Lead acid batteries also have to be refilled with water every few weeks. Again this can be a burden especially if you have a large battery bank. With a lithium battery, this is not necessary.

Key Takeaways About These Calculations

As you can see, calculating your solar usage can be really difficult. Because there are so many moving factors, we cannot give you an exact answer to what solar panel you should get.

Instead, you will need to do the math for yourself based on your own expectations and requirements.

Although this is a bit of a disappointing answer we would imagine, its the best answer we can provide. If you are not willing to do the calculations for your battery, we wouldnt recommend opting for a solar system in the first place.

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