Charging Battery While Connected To Inverter: The Best Way

A power inverter is great for energy needs. It can easily take battery DC power and convert it to AC power. However, as you use that AC electricity, your battery life starts to go down, and you need a charge.

Eventually, a power inverter will leave you with a dead battery unless you can charge your battery while connected to an inverter.

This post will review how to easily charge your battery power while connected to an inverter, including:

  • Power source options
  • How to connect the charging system

Following the outlined method below, you can ensure uninterrupted power by charging your battery while connected to an inverter.

Table of Contents

Power Inverter

As we dive into power source options and using a battery charger, it’s important to understand how the power inverter gets its energy.

Most inverter set-ups have an inverter (converts 12 Volt DC power to 120 Volt AC power) and a power source (usually a single battery or battery bank).

Inverter uses the battery to generate AC power.

As the inverter works and provides AC electricity to things such as lights and appliances, it can easily drain the battery’s DC power. This means you must find a way to charge the battery continually so your inverter can keep giving the AC power as needed.


The most important component of your power inverter setup is the battery. Why? Because it is the source of your energy. Whether you have a single battery or multiple batteries, the need to charge is always there when using an inverter.

Your inverter battery is likely a deep cycle battery. Deep cycle batteries work best when used with an inverter as they provide consistent power and can be discharged to a low battery voltage without damage. Verses a car battery, which uses a starter battery and is not designed to give consistent battery capacity. But rather gives a quick burst of energy to start a car.

And regardless of your battery type, the method to charge while on an inverter is the same. Whether you have a lead acid battery, AGM battery, or lithium batteries, the charging method is still the same. The only difference is the setting on your charging controller, which we will start to review now.

Solar Power

Solar power is the most common way to charge your battery while connected to an inverter. It acts as a battery charger that provides constant voltage to keep your battery charging. By acting as a DC battery charger, a solar system will give voltage while it converts power from the sun.

Solar power is preferred because you can charge an inverter battery without electricity. It is great when you are off the power grid without utility power. It is also great for a power outage, and you need backup power. With solar power, you can keep that battery backup charged while connected to your inverter.

Let’s look at the components you need and how to set up your solar system.

Solar Panel

We can all agree that getting a solar panel is the first step in charging solar. These panels come in many sizes and watt ratings, usually 100 to 200 watts per panel. Since the sunlight is not always constant, try to get the largest solar panel that will work for your setup. The more watts to a panel, the more power you can harness to your solar battery.

On a recent trip, I went where there was no shore power. Knowing this, I brought my solar system to keep my house batteries charged. I had plenty of sunshine during the first half of the trip and could keep my RV battery charged. The second half of the trip was cloudy, and I needed to run my generator every day to get the power I needed. Had I had more panels, it may have given me the power I needed on cloudy days.

Solar Charger

When using a solar panel, you cannot directly wire from the panel to the solar battery. You will need a solar charge controller. A solar charge controller is like a battery monitor that regulates the voltage from the panel so you get the 12 volts you need to charge. And it also regulates your charge so you don’t overcharge your battery.

Solar panels need a charge controller.

In addition, a solar charger also adjusts the charge as needed for different battery types. Even though all deep cycle batteries can provide 12v DC power, they each take a charge differently. Your charge controller should have different settings for AGM battery or lithium battery. Confirm what battery you have and make that is what your solar controller is set at.

Some solar panels come with a charge controller, but most do not. That is because if you are using multiple solar panels, you will only want one charge controller connected. So check your specs on the panel and see if a separate charge controller is needed.

Connecting Charging System

Connecting your solar system to your inverter battery is a simple process. It is very similar to all other battery connections, where you connect to the negative and positive battery terminals.

Step 1: Connect your inverter to the battery as usual

Your positive and negative cables will be connected to the correct battery terminal. Your inverter should be functioning just like it has always been at this point.

Step 2: Connect the solar panel to the charge controller

The solar panel and charge controller connect just like any other battery connection. You will see a positive and negative wire coming out of your solar panel (red is positive, and black is negative). You will need to connect these wires to the solar terminals of your charge controller.

Charge controllers usually have four terminals. Two are for the incoming solar panel, and two are for the outgoing battery. You will now need a set of positive and negative wires that go from the controller to the inverter battery. These should be the same gauge as your wires going from the panel to the controller.

Connect solar and battery wires to the controller.

If you set up multiple solar panels, you will wire each panel to each other, and the final set of wires will go to the controller. Please note that controllers are rated by amps, so you will need to confirm you have the correct size controller to the amount of solar panels. My setup was a 100-watt solar panel with a 10 amp controller. By using simple math (100 watts / 12 volts = 8.33 amps of solar output). Had I had more panels, I would need a higher-rated controller.

Step 3: Set your controller to the correct voltage and battery

The next step is to set your controller to the correct settings of your battery.  You should see settings for a 24v or 12v battery.  Ensure you set the correct voltage.  Most systems are 12V, but you will want to double-check that.

Also, set it to your battery type. You should see settings for sealed lead acid batteries or lithium ion batteries. Set to what you have for your setup.  

Step 4: Connect the solar controller to the inverter battery

The final step is to connect the solar controller to the inverter battery. The positive and negative wires from the controller will go with the battery’s positive and negative terminals.

By connecting this way, the solar panel will provide charge voltage while, at the same time, you are connected to and using your inverter.

Final Thoughts

Charging your battery while connected to an inverter is crucial for maintaining an uninterrupted power supply. Prolonged use of the inverter can deplete the battery, leaving you no power. To address this, solar power is the most preferred method for charging the battery while using the inverter, especially in off-grid situations or during power outages. Setting up a solar charging system involves using a solar panel, a solar charge controller, and proper battery connections.