Welcome back, everyone! This is Beat The Bush. Many of you have asked for a detailed explanation of my grid-tie inverter setup. In my previous videos, I didn’t cover the schematic layout and connections thoroughly. Today, I’m going to walk you through the entire setup, share my observations over the past few months, and address concerns about safety when utility workers turn off the power.

 

The Grid-Tie Inverter Setup

Basic Components

Here’s a quick overview of my setup:

• Solar Panels: I have two solar panels wired in series, creating a 24-volt system.
• Grid-Tie Inverter: A 500-watt grid-tie inverter that converts the DC power from the solar panels to AC power that can be fed back into the grid.
• Power Cables: The cables from the solar panels are doubled up to reduce resistance.
• AC Output: The inverter’s AC output is connected to a power strip that plugs into the wall.

Connecting the System

 

 

The power cables from the solar panels are connected to the inverter’s positive and negative terminals. The AC output from the inverter is plugged into the wall outlet through a power strip. When the inverter is turned on, it feeds power back into the grid. A kilowatt meter is used to measure the power being fed into the wall.

 

Safety Concerns and Testing

Utility Workers’ Safety

 

A common concern is whether the grid-tie inverter will feed power back into the grid when utility workers turn off the power, potentially causing electrocution. I tested this by unplugging the power strip from the wall. The inverter shuts off immediately, indicating that it does not feed power back into the grid when disconnected from the wall outlet.

 

Verifying with a Voltmeter

To confirm, I used a voltmeter to measure the AC voltage. When the power strip is unplugged, the inverter shows no voltage, proving it does not feed power back into the grid. The inverter senses the presence of 110 volts from the grid before feeding power back, ensuring safety.

 

Detailed Schematic and Operation

Solar Panels and Series Connection

The two solar panels are connected in series, doubling the voltage to 24 volts. This series connection helps in reducing the number of connectors needed. Each panel has an optimal operating voltage of around 17.9 volts, making the total system voltage approximately 36 volts for maximum power extraction.

 

Grid-Tie Inverter and Maximum Power Point Tracking

The grid-tie inverter adjusts the voltage to extract the most power from the solar panels. It operates using Maximum Power Point Tracking (MPPT) technology, which ensures that the voltage is optimized for maximum power transfer. This is why the voltage across the terminals reads 35 volts instead of 24 volts.

 

Measuring Power Output

The kilowatt meter helps in monitoring the power being fed into the wall. With the solar panels generating power, the inverter feeds it back into the grid, reducing the overall electricity consumption from the utility company.

 

Safety Mechanisms and Circuit Breakers

Circuit Breaker Integration

The AC output from the inverter is connected to the circuit breaker, which is then connected to the utility meter and back to the grid. This setup ensures that any excess power generated is fed back into the grid.

 

Grid Disconnection and Inverter Shutdown

In case of a grid disconnection, the inverter detects the absence of the 110 volts from the grid and shuts down automatically, ensuring no power is fed back into the grid. This safety feature protects utility workers from potential electrocution.

 

Optimal System Performance

Efficiency and Power Generation

Despite the panels being rated at 100 watts each, I usually get around 75 watts per panel. This discrepancy is due to various factors such as dust on the panels, weather conditions, and the angle of sunlight. However, the system has performed well, generating up to 140 watts on a good day.

 

Cost-Effective Cabling

To save costs, I used speaker cables for the connections, doubling them up to reduce resistance. This method proved effective and economical compared to purchasing expensive pigtail cables.

 

Series vs. Parallel Connections

There was a concern that in a parallel connection, the current would flow through the wire with the least resistance. However, the current is distributed proportionally between the wires, ensuring balanced current flow and reducing the load on individual wires.

 

Cleaning and Maintenance

Regular maintenance, such as cleaning the solar panels, is crucial for optimal performance. Dust and debris can significantly reduce the efficiency of the panels. Keeping them clean ensures maximum power generation.

 

Conclusion

This detailed explanation of my grid-tie inverter setup should help you understand how to connect and operate such a system safely and efficiently. If you’re considering a similar setup, ensure you have a contract with your utility company if you plan to feed power back into the grid.

 

Final Thoughts

Thank you for watching and I hope you found this guide helpful. If you’re interested in the products I use, check the links in the video description below. Don’t forget to like, comment, and subscribe, and hit the bell icon to stay updated with my latest videos.