 # What size solar panel to charge a 9v battery?

Using a solar panel to charge a 9v battery is a simple task. We are going to talk about in this article what is the size of the solar panel, how to make the circuit, how long takes charge the battery, and many other things.

When we are using solar power to charge a 9v battery the best solar panel is a 9v solar panel. Because 9 volts battery needs 9 volts current to charge the battery. If you are using a higher voltage solar panel than the battery needs the battery will be damaged probably. And if you are using a lower voltage solar panel to charge this battery the battery will not charge.

## How to charge a 9v battery using the solar panel?

To make this circuit you don’t need many items. If you are using a 9v solar panel to charge a 9v battery, additionally you need wires only. To make this circuit you can directly connect the solar panel to the battery through the wires. When you are connecting wires connect the positive terminal (+) of the solar panel to the positive terminal (+) of the battery and negative terminal (-) of the solar panel to the negative terminal (-) of the battery.

## How long does it take a battery to charge?

It depends on the AMPERES (amp) and VOLTAGE of the battery, and WATT (W) of the solar panel. Let’s take an example to make this easier to understand. If you are using a 9v 1-amp battery and using 9v 3W solar panel to charge the battery then it takes 3 hours to charge the battery.

How does this happen?

First, we should know how much power will be consumed to fully charge a battery. We can get the power in electricity by multiplying volts (v) from amperes (amp). So we can get the power required to fully charge a battery by simply multiplying the voltage value of the battery and amperes of the battery.

According to this simple theory to fully charge a 9v 1amp battery we need a 9 Watt-hours (9W) power supply. As we have 9 volts 3-Watt power supply it only supplies 3-Watt power per hour. So, it takes around 3 hours by the solar panel to supply the total power battery required.

## Can you charge a 9v battery with a 12v solar panel?

Yes, you can charge your 9v battery using a 12v solar panel but if you connect that panel directly to your battery it will damage your battery. Therefore, you can use a voltage controller to lower your solar panel voltage.

What is a voltage controller?

The voltage of your solar panel should be equal to the voltage of the battery you are using. If your solar panel gives a higher voltage than your battery needs, it will damage your battery instantly. So, you can use a voltage controller to lower the voltage.

The voltage controller is a device that limits the voltage of the power source. Its role is to ensure that the electrical equipment you use is properly supplied with the required voltage.

## Can you replace the voltage controller?

The function of the voltage controller is to reduce the voltage to the level required by your battery. You can simply use a bulb with the voltage you want to reduce instead of a voltage controller. Let’s make this more clear by an easy example.

Example: if you want to charge a 9v battery but you have a 12v solar panel you should reduce 3 volts to prevent overcharging. This is where the voltage controller is used. Instead of a voltage controller, you can connect a 3 volts bulb in series with the solar panel or battery.

## Can you charge a 9v battery with a 6v solar panel?

Whenever we select a solar panel that fits a battery, we have to consider the voltage of that battery. Always the voltage of the battery and the voltage of the panel should be the same. If the voltage on our panel is too high, it can be reduced to the aforesaid acre and connected to the battery. But if the voltage on your panel is less than the voltage on the battery, the battery will never charge.

## Can you use two 4.5v solar panels for a 9v battery?

Yes, you can connect the same voltage multiple solar panels together. Even if you add several panels of the same voltage to power your circuit, it does not matter if the total of those powers is the same as your battery. There have two ways to connect solar panels.

NOTE: Do not connect different voltage solar panels. It can damage your circuit.

How to connect a couple of solar panels for this circuit?

There are two ways to connect solar panels.

• Parallel
• Series

Parallel way

If you use a parallel way to connect the solar panels the voltage does not increase but the amperes are increasing. So this way is not suitable for your system.

Example for the parallel way: if you are connecting 4.5v and 4.5v panels in this way. Still, the output voltage is 4.5 volts.

Series Way

If you are using a series way to connect solar panels the amperes do not increase but the volts are increasing. According to this circuit, this is a suitable way to connect solar panels.

Example for the series way: if you are connecting 4.5v and 4.5v panels in this way. The output voltage is 9 volts.

## What are the best batteries for this circuit?

Another important aspect of this circuit is the battery. When choosing a battery for this, you must choose a rechargeable battery. Or the power from the solar panel cannot be stored. There have 3 battery types that can use for the solar power system.