How To Connect Solar Panels To Battery

If you want to explore the realm of off-grid living, then you are going to need to know how to connect solar panels to a battery. Solar panels and batteries both come in a range of voltages and those voltages generally never match. So you need some sort of converter, regulator, or controller between the solar panel and battery.

In most cases, a solar charge controller is used to connect a solar panel to a battery. Solar charge controllers come in various shapes, sizes, costs, and power output levels. Regardless of which solar charge controller you have, connecting a solar panel to it is pretty straightforward. All you have to do is match the + and - connections on the solar panel to the + and - panel input connections on your charge controller. After that, the + and - connections for the battery need to be attached to the corresponding + and - connections on the solar charge controller.

In this article, we will explain a little about how solar panels and batteries work. We will also discuss the battery charging process and explain how to connect solar panels to batteries.

Parts Required To Connect Solar Panel To Battery

• Solar panel
• Battery 
• PWM or MPPT solar charge controller  
• 12 gauge wire
• Battery connectors
• Inline fuse holder
• 15A fuse

Tools Required To Connect Solar Panel To Battery

• Screwdriver
• Wire stripper
• Heat gun
• Scissors or wire cutter
• Multimeter

How To Connect Solar Panels To Battery

Never connect a solar panel directly to a battery. If you do, you run the risk of damaging the battery and solar panel. There has to be some sort of regulator or controller between the two components.

Also, it's important to use a fuse. A solar charge controller can be thought of as two separate circuits that connect in a controller way. So, each one of those circuits needs to be fused. Generally speaking, fuses are placed on the positive end as close as possible to the source. 

To make the cables, cut two pieces of wire to the length and strip both ends.

To connect one of the fuse holder wires to your battery cable with a wire connector, start by placing a piece of heat shrink tubing on the wire you are going to connect to the fuse. A 10 gauge butt splice connector works well to make the connection. After that, move the heat shrink tubing down the wire until it covers the connection. Heat the heat shrink until its form-fitting around the connection.

Either crimp or solder the battery connectors onto the wires. After that, shrink-wrap the connections the same way you did above.

Connect the Battery to the Charge Controller

Connect the negative battery terminal to the negative terminal on the controller first. After that, connect the positive battery terminal (which should be fused) to the charge controller's positive connection.

Once you make a connection, whatever charge controller you are using will light up, turn on, or otherwise indicate that it has power. If you have a programmable charge controller, this is when you can take a look at its settings and make sure everything is reading correctly. Many charge controllers default to lead acid, so go into the settings and make sure it's set to the correct battery chemistry.

Connect the Solar Panel to the Charge Controller

The overwhelming majority of solar panels have cables with MC4 connectors. So, to be able to connect your solar panels to your charge controller, you will need MC4 solar adapter cables.

MC1 solar adapter cables are basically a length of decent-gauge wire that has an MC4 connector at one end and is stripped on the other side. Most solar charge controllers have screw terminals to make the connections.

First, attach the negative line for the solar panel to the positive solar panel input on the charge controller. Then, attach the negative cable the same way. 

Put the Solar Panel in the Sun

It's critical for the solar panel to be in direct sunlight. To get the most energy possible out of your solar panel, it would need to be pointed directly at the sun. This is not possible without motors and motor controllers and several other key pieces of infrastructure.

The next best thing is to place the solar panel at a 45-degree angle and rotate it so that it faces the point in the sky that the sun reaches it at its highest. This will ensure you get the most energy out of a static, non-moveable solar panel.

Can I Connect A Solar Panel Directly To A Battery

No. You cannot connect a solar panel directly to a battery. A solar panel has a varying voltage range that is based on how much solar energy it is receiving and how much of a load it has on it. This varying voltage is not something you can directly charge a battery with. Connecting a solar panel directly to a battery will damage one or both.

What Goes Between A Solar Panel And A Battery

A charge controller is the most common device to place between a solar panel and a battery. Charge controllers widely range in price and feature set. There are high-current self-contained charge controllers with LCD displays and there are also small, low-power charge control modules.

How Do You Hook Up A 12v Solar Panel To A Battery

A 12V solar panel can be hooked up to a battery with an MPPT charge controller module or an all-in-one solar charge controller.

What's The Difference Between A PWM and MPPT Solar Charge Controller?

PWM stands for pulse width modulation and MPPT stands for maximum power point tracking. Both types adjust charging rates based on the battery's state of charge. This allows charging a battery closer to its maximum capacity and prevents overheating.

PWM vs MPPT 

Both charging technologies have their advantages and disadvantages. Generally speaking, MPPT is the better choice for most applications, but as far as which one to use, PWM vs MPPT solar charge controllers, that really comes down to several factors including but not limited to load size, cost, and weather conditions.

Temperature 

If you live in a cold climate, an MPPT solar charge controller is best for you. This is because as solar cells increase in temperature, their operating voltage goes down. 

So, in colder climates, solar panels generally have a higher operating voltage than they would in a hotter region. In these cases, an MPPT controller is able to make use of the excess voltage to charge the batteries.  This makes it so that MPPT controllers can capture up to 25% more energy than a PWM controller in colder climates.

Array And Load Size

In some scenarios, there is more power coming from the solar array than what is needed for the load. In these cases, the batteries pretty much stay fully charged all the time. A PWM controller is perfectly capable of efficiently maintaining a system like that without the added complexity and expense of an MPPT solar controller.

Cost

Generally speaking, MPPT solar charge controllers are more expensive than their PWM counterparts. The higher efficiency of MPPT controllers warrants their higher cost, but only in conditions where MPPT can provide an increase in solar charge performance. To know which is best, MPPT or PWM, you have to consider several factors.

As you would expect, the cost is one of the most important driving factors when choosing either MPPT or PWM solar charge controllers.

Conclusion

If you are wanting to set up your own off-grid energy system, then you are going to need to know how to connect solar panels to a battery. The good news is that it’s pretty easy.

Generally speaking, a solar charge controller is used to connect a solar panel to a battery. Solar charge controllers, modules, and boards are available in various sizes and power output levels. As you would expect, solar charge controllers with a higher power output are more expensive. Connecting a solar charge controller is easy. Simply match the + and - connections on the solar panel to the + and - solar panel input connections on the charge controller. Then, you just need to connect the + and - connections for the battery to the corresponding + and - battery connections on the solar charge controller.

We hope this article helped you learn everything you needed to know about how to connect solar panels to batteries. Thanks for reading!