Solar Panel Inverters: Types – Repairs & Connecting

Solar panel inverters are one of the major components of a solar system. If you need to know more about inverter types, repairs, and connections, you’re in the right place.

Many solar arrays do not have a solar battery storage system and run energy from the array through the inverter. 

You do want to make sure that the type of inverter you use matches the capabilities of the solar panel or array. We will get into all that in a minute.

First, you need to know that you should never work on a solar panel while it is producing energy.

Doing so is an excellent way to get electrocuted or cause arcing, which will fry solar components. A solar inverter for a home solar array can run a couple of thousand dollars.

The second thing to know is that safety is always job one. Be safe. If you don’t know what you are doing, hire a professional. 

In this article, we discuss:

  1. Different types of solar inverters
  2. Repairing Solar Inverters
  3. Pairing the solar inverter to your array or panel
  4. Safety issues when working with solar. 
Controlling solar panels with a mobile phone

What are the Different Types of Solar Inverters?

There are four basic types of inverters, and each has a different kind of usage. They are:

  1. String Inverters 
  2. Microinverters 
  3. Hybrid Inverters
  4. Optimized String Inverters 

String Inverters 

String inverters gather energy from a string of solar panels. That can be a single panel or all of the panels in the array.

There are a few string inverters on larger arrays that manage the power flow of a portion of the panels in the string.

The term “string” comes from the way the panels connect. It is one string of wires that leads to the inverter. 

String inverters are one of the most common types of inverters, especially on older solar arrays. As technology advances, new types of inverters become more affordable and available.

As a result, they are also one of the least expensive inverters on the market.

Microinverters 

Microinverters invert the power from a single solar panel. 

These are a newer technology, and they help address some of the issues that string inverters have. 

One of those issues that string inverters have is that when one solar panel loses efficiency, all the panels on that string lose efficiency.

One situation that causes the loss of power on a panel is shading. With a microinverter, shading still occurs, but the rest of the panels are not affected. 

Microinverters are usually installed directly to the solar panel as part of the panels manufacturing process.

Therefore, it would be unlikely that you would need to connect a solar panel to a microinverter. Instead, you would replace the entire panel. 

Another big difference between string inverters and microinverters is the warranty. Microinverters have contracts that match that of the solar panel.

Generally, that is about 25 years.

A string inverter has a much shorter warranty which can range from two years to ten years. Solar panels typically have a 25-year warranty. 

Hybrid Inverters 

Hybrid inverters are the most complex in that they can handle DC voltage and AC voltage at the same time. 

You usually see hybrid inverters on systems with a solar battery backup system and are still connected to the grid (Grid-tied.)

One advantage of hybrid inverters is that you can use grid electricity to charge solar batteries. It sounds a bit odd, but in big storms or other heavy weather or smoky conditions, your solar array produces less energy.

Therefore, it is wise to keep your solar batteries fully charged during that condition if the grid-tied connection loses power while your solar array is not performing at peak efficiency. 

Another reason you may need a hybrid inverter is when the home or business is grid-tied without a battery back but when there is the intention of adding a battery storage system later. 

Optimized String Inverters 

Sometimes called power optimizers, optimized string inverters are similar to microinverters. However, they are connected to each solar panel rather than to a string of panels. 

These are repairable at the roof level but may also pose more significant risks.

They feed to a string inverter, so should that inverter stop you lose power from the entire string of panels.

They also send high DC voltage to the inverter, and some argue that it increases the risk of fire compared to microinverters. 

Can You Repair Solar Inverters?

Generally, you cannot repair a solar inverter. That is not to say inverters cannot be repaired. When they fail, the problem with most solar inverters is that they must go back to the factory for repair.

How that process works depends on the terms of your solar warranty.

Given that an inverter can cost several thousands of dollars, they are a sticky subject for homeowners. 

How Long Do Solar Inverter Repairs Take?

If your inverter fails and must go to the factory, repairs can take weeks if not a month. That potentially is a month without power from that inverter.

For microinverters, the key is usually to replace the panel and inverter. The cost for doing so is generally under $500 but will depend on your solar warranty.

Issues such as labor are another matter. Some warranties do not cover labor or travel time and may only cover the cost of parts. 

Situations like this are why people wonder how to connect a solar panel to an inverter without a battery backup system.

The reality is that it is not difficult if you understand basic electrical fundamentals. The majority of inverters are plug-and-play, though you do see hardwired inverters, especially on older systems.

The replacement of a hardwired inverter should be by an electrician and preferably one with solar experience. 

Can You Use Any Inverter? 

No. The inverter must match your system both in terms of voltage and function.

If you are not using batteries, you need an inverter that can handle both DC and AC voltage since the power from the array is going to the home. Homes use AC voltage, and solar arrays produce DC voltage.

It is the job of the inverter to invert DC to AC voltage. You will likely need a voltage regulator also. Homes run 110 and 220-volt plugs.

Voltage must be regulated not to cause plug malfunction, damage to appliances, or a fire. 

Off-grid systems without a battery backup are rarer these days. This is because the power from the solar array would be available only when the array produces enough voltage to meet the home’s requirements.

Without enough energy, you’d be in a brownout, and as a safety precaution, most inverters will shut down when the power supply falls below specified voltage. 

How To Connect A Solar Panel to An Inverter Without Batteries

  1. Make sure that the inverter is rated for the panel or array. 
  2. Power down the array or panel 
  3. Use a voltage meter to make sure the power is low rather than high voltage. 
  4. Disconnect the old inverter by unsnapping the plug. If the inverter is hardwired, use a PV electrician. 
  5. If using a solar array kit, be sure to read the entire set of instructions before starting. Most solar inverters these days have snap connectors, making them easy to install. 
  6. Snap the connector from the solar array to the solar inverter. 
  7. Reinstall the inverter – many bolt to the side of a building. If you are working on a power-optimized solar panel or a solar panel with a microinverter, you would attach the new inverter to the panel and connect the snap connections. 
  8. Retest the voltage to the inverter to make sure the inverter and panel are working. 

Should You Connect A Solar Panel to An Inverter without Battery Backups?

It is always advisable to use a professional rather than the DIY approach to anything that involves electricity. If you do not know about electrical power and circuitry, be safe and hire an electrician to help. 

SOURCES 

Solar Panel Maintenance FAQ

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