Our System Overview: The Inverter
Hey folks, we’ve been talking about our solar power system and how we use it. A lot of people are curious about off grid living and solar, so I thought we’d cover how system details.
The Inverter
Our system has a Xantrex SW 4024 model solar inverter. The SW, stands for Sine Wave, which we’ll talk more about in a minute. The ’40′ means it is a 4000W inverter, which is the maximum output wattage. So if we turned everything on, we would could run a maximum of 4000W worth of appliances before the inverter would shut down. It has nothing to do with how much energy we can use total in a day, just how much we can run at one time.
The 24 refers to the input voltage. The voltage coming out of our batteries is set at 24 volts, so we need an inverter than can handle that voltage. This unit also is built for off grid and/or grid tied with battery backup. This mean it has the capability to take voltage from batteries, the grid, or a backup generator. We have a generator, which we’ll cover in a subsequent post.
Riding the Wave
So what is the inverter do in the system? Inverters are designed to make waves, literally. They take the power from the batteries which is DC, or direct current, and make it AC, or alternating current. DC current flows steady like water out of a hose. AC flows in waves, or imagine someone was constantly turning up and down the hose faucet so that the water flowed out in waves. Our electric grid and most of our appliances take AC power, so we have to convert solar panel DC power and make it nice and wavy for our home.
This is a sine wave, which is what a inverter produces for your power.
- The Low Battery Voltage, which is when the generator kicks on to fill the batteries
- The Low Battery Cutoff, which shuts off all power so that they batteries don’t get drawn down too low
- Bulk, Float, Absorption, and Equalization times, which we will cover when we talk about the batteries.
Pure Sine Wave vs Modified Sine
If you look at inverters, you’ll find there are many types. For whole-home applications, as opposed to small units for cars or chargers, you can’t beat the pure sine wave. The difference is dramatic. A modified sine wave actually puts steps in the wave, picture a stairway going up and down the approximate line of the sine wave, and you’ll get the idea. It is much less efficient for your appliances and many modern electronics (plasma tv’s, computers) can actually be damaged by the modified sine.
Overall we are very happy with the Xantrex, we’ve had it for about 3 years and have had no problems. We have many neighbors with the same unit, some have had issues, but they have found ways and people to fix them.
