How To Connect A Solar Panel To A 12 Volt Battery?

If you’ve made the decision to set up and install a solar panel kit, you’ll likely have some questions about exactly you’re going to connect it all up.

Well, you’re not alone in that – many people are installing a solar panel system for the first time every day!

How to connect a solar panel to a 12 volt battery

Whether you’re installing multiple solar panel kits with many highly efficient solar cells, or just a single solar panel, you’ll be thinking long and hard about this, especially if you’re one of the people who are going all in on solar and making permanent setups!

Well, this article will give you a rough idea of just how all of your kit goes together, and what the components actually do!

What You’ll Need

  • Solar panels and a battery – although this should go without saying!
  • Charge controller – this regulates the power that comes from your solar panel before it enters your battery, or array of batteries. This is another essential part of the whole solar array. It prevents your batteries from overcharging.

An overcharged battery is something to be avoided, as it can cause permanent damage to the battery, affect its lifespan, and can even be dangerous to you too!

  • Wiring diagram – whether you’re using a manufacturer’s wiring diagram, or you’re having to customize things to fit your exact setup, it’s important to have an electrical diagram with you throughout the process.

Without a clear plan laid out, you’ll really struggle to correctly and safely connect up your solar panel system. Even if you’re only connecting a single panel, single battery, and controller together, having a wiring diagram will help you out so much.

  • Wire – make sure that it’s the right gauge required for your equipment.
  • Electrical Metallic Tubing – this is likely what you’ll be using to mount your solar equipment.
  • Tools – screwdrivers, wire cutters and strippers, etc

Mounting And Installing the Solar Panels

One of the most critical things that you can do is something that needs to be done before even a single screw is tightened – you need to pick somewhere good for your installation to go!

There’s no point putting your solar panels somewhere where they won’t catch any sun, for a start. This is a crucial factor to consider when it comes to how much power you’ll get! You’ll need to take some time and do the work beforehand to find out where the best place to put your panels is so that they can get the absolute most sunlight possible.

Get this wrong, and you simply won’t be able to get the optimum amount of power from your solar panels.

Even if you’re using a motorized system, you still have to do your planning – maybe even more so! Just because your panels can move on their own, doesn’t mean that you can just stick them anywhere and expect maximum efficiency. Take your time and plan this out properly – you don’t want to have to do the installation again!

Make sure, if you’re using a motorized setup, that you have clearance all around where you’re installing the panels – after all, you really don’t want your solar panels to bump into anything when they’re moving about!

Mount the panels securely and safely, according to the instructions from your supplier. Make sure not to cut corners – get it done right the first time!

You’ll have to find somewhere appropriate to place the charge controller, and the 12 volt battery too. Make sure you’ll be able to have access for wiring, of course!

If you’re installing more than one solar panel, then no matter how many more you have, you’ll have to choose whether you’re going to wire them up together in series or parallel.

Make sure when wiring solar panels to install following manufacturers instructions and any appropriate electrical code, using fuses, slice boxes, and junction boxes to help protect your circuitry.

Connecting the Panels to Charge Controller

Now that you’ve got the solar panels of your solar power system installed, it’s time to connect your solar panels to the charge controller. Charge controllers are a really important part of the whole setup.

They provide a safe interface between your solar panels and your battery – providing essential safety measures that protect you, your solar power installation, and your home, against overcharged batteries.

Wiring these should be fairly straightforward – be sure to follow the manufacturer’s instructions for locating the correct terminals.

It’s possible to fit and connect a solar panel system without the use of a charge controller if you’re using much smaller solar panels in the 1 to 5 watt range – but for most 100 watt setups, most proper guidelines will recommend that you use a charge controller.

There are two types of charge controllers, and they typically work by using either method to vary the voltage and/or current output by the solar panels.

The first type, PWM (Pulse Width Modulation), essentially works like a switch that turns very rapidly on and off to regulate the voltage and/or current. It’s a very simple technology, but of the two it’s by far the least efficient, with efficiency as low as 40% in some cases.

The other type, MPPT (Maximum Power Point Tracking), use more complex technology to track the energy in the solar setup, coming from the panel and going to the batteries.

The main upshot of this for the end user is increased power efficiency – up to 30% more efficient than similar PWM charge controllers – at the cost of increased price. An MPPT charge controller will typically be a fair bit more expensive than it’s PWM counterpart.

If you’re less concerned with the efficiency gains that you can get from using an MPPT controller, then it might well be worth saving money by buying a PWM controller – but in the long run, an MPPT controller might work out a better buy.

Connecting the Charge Controller to the Battery

Now that the charge controller and solar panels are connected, it’s time to wire the charge controller and the battery together. Make sure not to use too light a gauge wire, for safety reasons.

Always follow the instructions as laid out by the manufacturer of your equipment when connecting your solar charge controller to the battery – as you should do when connecting any and all parts of your solar panel system!

This should be a relatively straightforward job, just as long as you pay careful attention to the instructions as laid out by the manufacturer of your equipment.

Power Inverter

If you’re intending to use your solar power kit to power devices that use AC (Alternating Current), however, then you’ll need one more component – an inverter. Seeing as the vast majority of electronic devices use AC, this is likely going to be a part of your solar panel kit too!

An inverter is actually a pretty straightforward device. All it does is convert DC (Direct Current) into AC – but it’ll be one of the most important parts of most people’s setups.


Above all, remember that you don’t have to do any of this if you’re not feeling confident. If at any point you don’t feel like you can do a safe job, the smart thing to do is to get a professional electrician to do it for you.

Sure, it’s going to cost more, but in the long run, you could well save yourself a lot of hassle and worry!