What does Power Inverters do?

You can think of a power inverter as the device that makes the energy your solar power system absorbs usable for your home or vehicle. The DC power produced by your panels isn’t compatible with your appliances, so an inverter converts the direct current (DC) output collected by your solar array into alternating current (AC) power. The AC power can then travel to your appliances safely and correctly, preventing any burnouts or shortages. 

What are the Three Types of Power Inverters?

• Pure Sine Wave Power Inverters

Pure sine wave inverters create reliable electricity without worrying about any interference. They operate very quietly and produce very smooth or pure sine waves, which look like evenly-spaced, rounded waves on a graph. Most modern appliances are designed for sine wave energy, making pure sine wave inverters popular for solar charge control.  

• Modified Sine Wave Inverters

With modified sine wave inverters, the polarity switches back and forth between positive and negative. On a graph, it looks like very squared-off waves that contain small steps throughout each wave. This production does create a minor humming sound, making modified sine wave inverters more noticeable than their pure sine wave counterparts. Because modified sine wave inverters create a more choppy energy flow, they are not compatible with sensitive electronic equipment, such as medical devices or laser printers.

• Micro-Inverter

As the name implies, a micro-inverter is the miniature form of a standard inverter attached to each solar panel’s back. These tiny devices have a long lifespan and allow you to monitor individual panel use. However, they tend to cost more, depending on how many you need in comparison to a singular standard inverter, and they may require more maintenance on your part. 

How Long will a 12v Battery Last with an Inverter?

Before answering this question, it’s important to know the type and wattage of your battery. These two factors will directly influence how long the battery will last with an inverter. Let’s show an example with a 12 volt 50Ah lithium iron phosphate (liFPO4) battery. The calculation we’ll need to use is:

                                                           Battery watt-hours (Wh) = amp-hour capacity x battery volts

The battery watt-hours for our selected battery would be 50Ah x 12V = 600 Wh. 

It’s best to run a depth of discharge (DoD) rate of 80% on this type of battery, even though it’s capable of going as high as 95%. That would mean the actual watt-hours would be 480 Wh or 80% of the initial 60Wh.  

To determine the run time for a 3000W pure sine wave inverter at 95% efficiency, you would divide your 480 Wh by 1000W, which gives you .48 hours, or 28.8 minutes.  

What Size Power Inverters do I Need?

Choosing the best inverter size means you first need to know how many watts per day your solar panel system will produce. You’ll also want to have this information to ensure you connect the right-sized battery capacity to your solar array. The general rule of thumb is your inverter’s capacity should be between at least 25% but more preferably 50% higher than the total wattage.