A solar inverter converts direct current (DC) power that solar panels generate into alternating current (AC) electricity. Since portable solar panels produce less energy than fixed panels, you might wonder whether an inverter is necessary.
Portable solar panels need an inverter to run most household appliances. You can do without an inverter in your solar power system if you only want to run DC appliances. If you require an inverter, select the right size and type because inverter choice can impact your system’s efficiency.
In this article, I’ll explain what could happen if you run solar panels without an inverter. You’ll also learn to choose the right inverter for a portable solar power system.
Risks of Using a Portable Solar Panel Without an Inverter
Solar panels can power some of your appliances and gadgets without an inverter. It can work for appliances requiring DC power or running on both DC and AC electricity.
You may require a DC-to-DC converter to run your solar power system without an inverter. This component allows you to regulate the voltage for your appliances. For example, the waterproof MGGi DC Converter (available on Amazon.com) lets you step down the voltage for small DC appliances.
However, many problems can arise if you run AC electronics on solar power without an inverter. Here’re a few of the risks you should be aware of:
- You risk damaging your appliance. Plugging an AC electronic into a DC power outlet can short-circuit and damage the internal components. If the appliance isn’t damaged, it may simply not work due to the improper power connection.
- You risk causing a fire. An AC appliance connected to a DC power supply can overheat and burn internal components. You may notice a burn from smoke and a bad smell. Depending on the severity of the heat, there may be a fire risk if inflammable items are around.
- You risk voiding the warranty for your electronics. You may lose the warranty for your AC appliances if you attempt to power them with DC electricity. As a result, running a solar power system without an inverter could cause you a double blow in that you lose your electronics and void manufacturer insurance.
- You can’t power all of your appliances. Many people choose portable solar panels to support their mobile lifestyle. These panels allow them to generate electricity anywhere they go. As a result, they can maintain a normal life in remote places without access to the power grid.
You may be inconvenienced if you run your portable solar panels without an inverter because you won’t be able to power some of your electronics.
How Do Solar Inverters Work?
Solar panels produce DC power. An inverter transforms the DC power into AC electricity that most appliances require.
Inverters are required in a portable solar power system to make the energy usable for most household electronics.
In fixed solar systems, inverters can handle several functions. Besides making solar energy usable for household appliances, an inverter supports integration with the power grid.
In a grid-tied solar system, the inverter converts the DC power into AC energy to make it compatible with the grid electricity. You may offset your utility bills by integrating your solar panels into the grid.
Choosing the Correct Inverter Type for Portable Solar Panels
Inverters are available in various forms based on the configuration and quality of power they deliver.
In most solar power systems, the inverter is typically the most complex and expensive component. Most solar power system failures are linked to the inverter. Therefore, choosing the correct inverter type can reduce problems when using portable solar panels.
Inverters fall into two major categories based on configuration: String inverters and microinverters. These inverter configurations are worth considering if you want to use solar panels without a battery.
Let’s look at how each of them works and their pros and cons.
String Inverters Work With Solar Panels in a Series Circuit
A string inverter operates with a group of solar panels wired in a series circuit. All the connected panels send their direct current to the single inverter that converts it into alternating current. As a result, a string inverter is also called a central inverter.
Here’re the pros and cons of a string inverter configuration:
Pros
- More affordable option: String inverters are typically cheaper to purchase than microinverters. Therefore, a string inverter configuration can be ideal if you want low upfront costs for a solar power setup.
- Easy troubleshooting: Only one piece of equipment handles power conversion in a string inverter configuration. Troubleshooting the problem can be easy if anything goes wrong because you only look at one location.
- Easy maintenance: Since you only have a single inverter in the system, cleaning dust buildups and controlling the temperature becomes easy. As a result, you can prevent inverter failures before they occur.
Cons
- Output depends on the poor performer: Since the solar panels are cabled in a series circuit, a problem with one panel affects the entire group. If one panel produces less power, the production of all the other panels dips.
- Difficult to upgrade the system: Expanding a solar power system with a string inverter configuration can be challenging. You may need to buy an additional or larger inverter if you add more solar panels to boost output.
- Short lifespan: String inverters’ warrantied lifespan ranges from 8 years to 12 years. Solar panels typically have 25 to 30 warranty years. You must replace the string inverter to keep your solar power system running.
The most significant drawback of string inverters is that the output depends on the lowest-performing panel in the chain. You can overcome this problem with power optimizers attached to each panel.
Although you incur additional costs in the setup, power optimizers increase the efficiency and output of solar systems in a series circuit. I recommend the SolarEdge P320 Power Optimizer (available on Amazon.com). This is an affordable yet high-performing add-on to solar panels. It also complies with rapid shutdown requirements.
Microinverters Work With Solar Panels in a Parallel Connection
Microinverters are modern components of solar power systems. They attach to each solar panel in the system individually to convert the power at the source. As the name implies, these inverters are tiny. They attach to the back side of the panel.
Here’re the pros and cons of microinverters:
Pros
- Maximum power output: Microinverters allow each panel to produce at its peak level regardless of the condition of other panels in the system. As a result, you can maximize output where panels have varying sunlight exposure.
- Easy to upgrade: Microinverters make it easy to start small and expand your solar power system over time by adding more panels with micro inverters. In string inverters, expanding the system may require larger equipment.
- Long lifespan: The inverter is one of the most significant investments in a solar power system. You can save money if you don’t have to replace the equipment frequently. Microinverters have a standard warrantied lifespan of 25 years.
Cons
- High purchase cost: Microinverters are typically more expensive than string inverters. Although microinverters allow you to start your solar power system small and expand over time, they require a significant upfront investment.
- Complex troubleshooting: Solar power system problems mostly start at the inverter. If you have multiple inverters in the system, it can be challenging to locate the exact source of the problem.
- More difficult to work with a battery backup: If you wish to save surplus power for later use, microinverters make the battery storage connection more complicated than the string inverter configuration.
Inverters also fall into two major groups by type of power quality or technology: Pure sine wave inverters and modified sine wave inverters.
Let’s examine how each of them works and their pros and cons.
Pure Sine Wave Inverters Can Fit Nearly All Applications
Pure sine wave inverters are also called true sine wave inverters. The electricity quality that pure sine wave inverters deliver can be compared to what you get from the grid, if not better.
These inverters have benefits and drawbacks that you should consider when setting up a portable solar power system.
Pros
- Suitable for power-sensitive appliances: Pure sine wave inverters deliver smooth electricity, ideal for power-sensitive electronics such as televisions and medical devices.
- Quiet electricity: These inverters deliver calm power, ideal for running audio devices. Therefore, this is the type of inverter to go for if you want to run recording studio systems.
- Compatible with nearly all electronics: A pure sine wave inverter will power nearly all appliances you may want to run. Moreover, most appliances only work to full capacity on pure sine wave electricity quality.
Cons
High upfront cost: Pure sine wave inverters are expensive to purchase. They can cost several hundred dollars over comparable modified sine wave variants. As a result, these inverters require a high upfront investment.
Modified Sine Wave Inverters Have a Narrow Application
The power quality that modified sine wave inverters deliver can run some appliances but not others. However, these are the best inverters for someone on a budget.
Here’s a look at the modified sine wave inverter’s advantages and disadvantages:
Pros
- More affordable: Modified sine wave inverters are cheaper than their pure sine wave counterparts. As a result, these are the inverters to go for if you’re looking to spend the least amount upfront on your solar power system.
- Can run many old appliances: If your tube television rekindles some memories, it would just be fine running on power from a modified sine wave inverter. Some old water pumps will also be happy with this inverter type.
Cons
- Produce rough electricity: Modified sine wave inverters deliver electricity in a distorted waveform. As a result, these inverters can be harmful to power-sensitive electronics. They can also confuse appliances with digital timers.
- Support a limited number of appliances: Only a tiny fraction of your appliances will work on modified sine wave electricity. As a result, you may be unable to run some of your electronics with this inverter.
- Produce noise: Because modified sine wave inverters deliver rough electricity, they cause noise. You’ll hear a buzzing sound from audio devices, fluorescent bulbs, fans, and other electronics.
- Waste energy: The distorted electricity from modified sine wave inverters causes energy loss through heat. Moreover, appliances that can tolerate modified sine wave inverters may consume more power than usual.
What Inverter Size Do You Need for Portable Solar Panels?
The Inverter size or capacity is given in watts. Inverter capacity for portable solar panels can range from 50 watts to 5,000 watts. An inverter’s capacity rating tells you how much load the equipment can handle.
Therefore, your power demand is a major factor in determining the right inverter size for your system.
There are two major inverter output rating levels: continuous rating and surge rating.
- Continuous rating: This number tells you the amount of load the inverter can handle steadily. It shows the power demand the equipment can supply over an indefinite period. It can also be called typical rating or usual rating.
- Surge rating: This number shows the maximum load an inverter can handle over a short period, usually from a few seconds to several minutes. Surge rating takes care of peak demand.
How To Determine the Right Inverter Size for Your Solar System
There are several methods for calculating the inverter size you need. When determining the inverter capacity, you want the equipment to match your power demand as close as possible.
Here’re a few steps to help you determine the right inverter size:
- Sum your appliances’ power demand: The power demand for most appliances is given in watts. Add up the wattage of your appliances and increase the total by at least 20%.
- The largest load in front: Use the largest load to determine the right inverter capacity if you don’t plan to run all your appliances simultaneously. You can choose an inverter that exceeds your largest load by 20% to 50%.
- Battery size guide: Aim to have at least 100Ah of battery capacity for every 1,000 watts of inverter capacity. Therefore, two 200AH batteries would require a 4,000-watt inverter.
Some appliances draw more power at startup than they need to continue running. For example, refrigerators and pumps consume more electricity than normal in the first few seconds they’re turned on. Therefore, your inverter capacity should exceed the load to handle the peak demand.
The surge capacity can be as much as three times an inverter’s continuous rating.
What Happens if You Overload a Solar Inverter?
Inverters shut down when overloaded. The equipment may try to cope with the power demand before it gives in. The inverter can produce excess heat as it struggles to meet the demand. The excess heat can reduce the inverter’s efficiency and lifespan.
While you don’t want to overload your inverter, you also don’t want excess capacity. Inverters consume electricity just to run. Therefore, the larger it is, the more energy it uses. Moreover, inverters are most efficient when running a load near their continuous rating.
If you’re interested in an inverter for portable solar panels, I recommend the Renogy Pure Sine Wave Inverter (available on Amazon.com). This equipment boasts an efficiency rating of more than 90%. It also has powerful cooling fans to prevent overheating so it can last long.
Summary
Portable solar panels need an inverter in most cases. You may use solar panels without an inverter if you only want to run DC appliances. The best portable solar power system inverter delivers smooth, quiet electricity.
