Can Solar Panels Charge Lithium Batteries? (Our Expert Take)

As the world paces towards an energy crisis, alternate energy sources are becoming more popular. One such is solar energy. A typical solar energy system consists of batteries, mounting tools, panels, inverters and other monitoring systems.

The solar panels convert the energy gathered from the sun, which is used as electricity. Since the shift from the grid to solar panels is happening very fast, it’s essential to know about the various elements in your solar power setup, especially the batteries. Nowadays, the demand for lithium batteries are on the rise.

But, can solar panels charge lithium batteries?

There are many types of batteries available, but today we will be focusing on Lithium batteries. So if you are planning to use these in your solar panel, here is all you need to know.

Can solar panels charge lithium batteries
Can solar panels charge lithium batteries

Can Solar Panels Charge Lithium Batteries? 

It’s possible to charge lithium batteries with solar panels; however, regular charging can damage them. Most batteries can be charged in three stages, acceptance, bulk, and float. Lithium batteries, on the other hand, have only two. 

The first stage of the lithium battery is similar to the bulk stage of other batteries. The amperage left after charging drains when it goes to the second and third stages. Store charging can also increase discharge and damage the batteries.

How do you Charge a Lithium-ion Battery with a Solar Panel? 

Mostly the process is simple; however, the method differs from one solar unit to another. Thus it’s essential to check instructions. 

How do you charge a lithium-ion battery with a solar panel? 

Charge controller required

There are two types of charge controllers MPPT and PWM. It’s advisable to use an MPPT charge controller. 

A PWM controller reduces the solar panel voltage until it is similar to the battery. The solar array will not run in full power in this case. However, with an MPPT controller, the controller adjusts automatically, so maximum current is in the battery.

Setting charge controller

It’s essential to set up the charge controller in a waterproof area. The controller, battery, and solar panels need to be well distanced with cables. Plus, the solar panel and other equipment need to be grounded. The controller can be mounted on any surface except metal.

Lithium battery cables

The lithium battery must be removed from the package, and the wires must be plugged into the right slots to proceed to the following stage. Thankfully, these wires are color-coded for positive and negative charges.

Plugging into the charge controller

Use the two loose battery wire ends and insert them in the respective positive and negative slots in the controller. Secure the wires with a screwdriver once placed. 

Place the MC4 connectors on the charge controller

Secure the charge controller wires with the MC4 connector at the end. Some solar kits don’t have an MC4 connector. In such cases, you have to buy it additionally. 

Connecting controller to solar panel

Once you have the charge controller wires inside the MC4 connectors, take the two and connect them to the solar panel. Most solar panels have MC4 connectors. 

Note: the male MC4 controller should be linked to the female MC4 on the solar panel and vise versa. 

Testing

Make sure all the wiring is secured. For this, give a slight tug to the wires for checking. Finally, switch on the charge controller if it does not turn on automatically. In the absence of an error message, your installation is complete.

Wait for the battery to charge

Once all the above steps are complete, you only need to wait for the battery to charge. The time required for the battery to charge depends on the sun hours, battery power, and solar array size. For instance, a 300W solar panel can charge a 12V 100ah Lithium battery in only 4 hours. 

Do Lithium Batteries Need a Special Solar Charge Controller?

You can charge a lithium battery with an MPPT or a PWM charger. However, an MPPT controller is a better option. Though these controllers are expensive, they extract more energy from the array. While using solar power, it’s always essential to get maximum usage from the batteries, panels, and inverters, and an MPPT controller allows you to do that. 

However, if you have a small battery, a PWM controller is suitable. These controllers drop the voltage to match the battery, which otherwise wastes the panel’s energy production ability. 

With an MPPT controller, the solar panels operate optimally, increasing the energy that goes in the battery; thus, MPPT is ideal for a lithium battery.

How Many Solar Panels Does it Take to Charge a 100Ah Lithium Battery?

A fully charged 12B auto battery requires three solar panels with 100 watts of power on each to recharge on a day. This is assuming that there is 4-peak hour sun daily. 

If the battery is drained to 50% of the capacity, it will require two solar panels with a 100-watt charge on each to fully recharge the battery in a day. 

How Many Solar Panels Does it Take to Charge a 200Ah Lithium Battery?

The number of solar panels required to charge a 200Ah battery will depend on whether or not the battery is completely drained of charge. Though 100% discharge sometimes happens in lithium batteries, it’s not a very common occurrence. Moreover, the discharge level depends on the battery type and design. 

Generally, a 200Ah lithium battery would require a 300-watt solar panel to charge itself completely. However, if there is a clear sky, the charging should not take more than one day.

How Many Watts do I Need to Charge a 12V 200Ah Lithium Battery?

You will need two 325 Watt solar panels with an MPPT charge controller and seasonal structure to charge a 12V 200Ah battery in five hours. The solar charge controller will protect the battery against high voltage and overcharging. Additionally, the seasonal design will increase the power generation from the solar panels seasonally. 

If you have a 12V 200 battery, you can calculate the number of panels required to charge your battery. For instance, if you have 8 12V 200 batteries, you will need 16 325 watt solar panels to charge them.

Conclusion:

With all the information here about Lithium batteries and their capacity, you can now install these and have energy sources to drive your daily needs. 

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