How to charge battery with solar panel

If you are looking forward to harnessing the most out of renewable solar energy, you should think about charging batteries with a solar panel. 

However, you can’t just directly connect your solar panels to the battery. 

That’s why we thought of sharing a step by step guide, which you can follow to connect the solar panels to your batteries in the right way and recharge them.

Get a charge controller 

You need to have a charge controller for recharging your batteries with a solar panel. But before you do that, you need to take a look at your solar panels and see their wattage. This is clearly indicated at the rear of your solar panels. In case if you don’t see it, you may get in touch with the solar panel supplier and ask. 

Or else, you may even use a multimeter and measure the output wattage of your solar panel when there is full sun falling on it. 

You need to make sure that your solar panel is not producing more power than what your battery can handle. Otherwise, your battery would overcharge and damage. This is why you should be careful to purchase the right charge controller.

Once you are aware about the solar watt rating of your solar panels, you will need to divide that as per the voltage of your battery. You can clearly see the voltage rating of your battery indicated on it. By dividing, you will be able to determine the amps required to charge the battery safely.

For example, let’s assume that your solar panel is producing 500W of energy. You are planning to recharge a 12V battery with it. 

By dividing 500W with 12V, you will end up with 42 amps. Hence, you should be purchasing a charge controller that is rated for 42 amps. 

Instead of just purchasing a charge controller, it is better if you can upgrade to a MPPT charge controller. It can help you to recharge your batteries with a better efficiency. That’s because such charge controllers can effectively regulate maximum voltage amount that your solar panels can send to recharge the batter


Mount your battery charge controller

Now you have the battery charge controller, and you will need to mount it. you need to be careful to mount the charge in an indoor location, as it is not weatherproof. You should also be careful to mount this to a non-conductive material, such as a piece of wood or a PVC panel.

Connect the battery charge controller with battery

Next, you will need to connect your battery charge controller with the battery. You may do it by wrapping the bare wires of your controller along with the battery posts. Or else, you may use ring connections that are fitting over the battery posts. No matter what, you need to make sure that negative wires are kept away from positive wires to ensure safety. 

Connect the wires to charge controller

Next, you will need to connect the other ends of the wires to your charge controller. You need to make sure that you are sliding the bare positive and bare negative wires to the right ports of your charge controller. 

After sliding, you may use a screwdriver, so that you can tighten all the screws. This will help you to properly secure all wires in place. 

When you are connecting the wires to your charge controller, you may think about using MC4 connectors. In general, the output wires of your solar panels would be fitted with the MC4 connectors. These are the long cylindrical shaped fittings, which are having male as well as female sides. 

To make sure that they are being connected properly, you should fit the wires that run from the charge connector along with MC4 connectors. This is where you should be attaching the bare ends of your input wires to the charge connector, in a way similar to how you attached the output wires. You can simply slide them to the input ports and use a screwdriver to tighten.

Connect charge controller with the solar panel

Now you have connected your batteries with the charge controller. Hence, you should move to the next step where you connect charge controller with the solar panel. 

After attaching the input wires into your charge controller, you will end up with two loose wires. Each of these loose wires would have a MC4 connector. 

You should match the male connector and female connector with opposite connectors on your solar panel accordingly. Then you should connect the MC4 connectors properly. As you connect, you will be able to hear a click sound. It will make sure that the connectors are properly sealed.

Double check connections and allow the battery to charge 

By this stage, you are done with connecting the battery with connectors. You can double check that your connections are working by just confirming output current on the charge connector. Most charge connectors available out there would come along with a digital screen. 

On this digital screen, you will be able to see the output that is flowing into your battery. In case if the reading is 0 when there is sunlight, you need to understand that there’s something wrong. Hence, you should double check all connections. 

If your charge connector is providing current to the battery, you can simply allow your battery to charge. The specific time that it would take for a battery to charge would vary depending on its size. 

Some other factors that would contribute towards the time that it would take for a battery to charge are the weather conditions and wattage of your solar panel. 

The digital panel of your charge connector will be able to provide you with an indication of battery recharging status. If the battery is fully charged, the connector will automatically stop the flow of current into it. 

Hence, you don’t need to worry about taking off the connection manually.

Final Thought

Now you know how to charge a battery from a solar panel. If you can continue to do this, you can make sure that you don’t have to spend any electricity to recharge batteries hereafter.