What to Know About Inverter Batteries

Solar power allows you to create a lifestyle that's not tied to the grid. It can give you the freedom to travel in a van, or the peace of mind that you'll always have power in an emergency.

A battery is a central feature of most renewable energy systems. If you want to convert to solar energy as your primary or emergency power source, you'll want to familiarize yourself with how inverter batteries work. Solar inverters play a vital role in these solar installations, enabling you to efficiently and safely power appliances and devices.

So what do you need to know about solar inverters to ensure a robust, safe, and efficient solar installation? This article will discuss different inverter types and how to use inverter batteries in solar energy systems.

What are inverter batteries?

Every solar energy system has three main parts: solar panels, solar charge controllers, and the inverter battery storage system. Grid-tied solar power systems don't necessarily need a storage system. But any off-grid solar system needs to utilize batteries to store the energy produced from solar panels.

The panels on a solar panel system work with sunlight to generate solar power. But once the panels have converted solar power into energy, the energy needs to be stored in a safe place if you want to use it later. Utilizing solar batteries or a battery bank will allow you to keep solar power for overcast days or emergencies.

Solar panels always output direct current (DC) electricity. However, in the US, most commercial electronics require alternating current (AC). The prevalence of AC electronics makes inverters an essential product for most off-grid power systems.

Inverters convert DC to AC, allowing a stable power stream to run from your solar panels and batteries to AC electronics. An inverter or inverter charger creates clean, renewable, and silent energy - so you won't have to worry about losing power to your favorite devices and appliances, even when you're on the road. You can use Renogy inverter batteries with off-grid systems in motorhomes, RVs, cabins, and van conversions.

Why do you need an inverter?

Any off-grid solar system will need an inverter. If you're installing an off-grid system, it likely means you want or need to produce and store enough solar energy to power your lifestyle - without having to tap into the electric grid.

Solar power can be stored in a battery or battery bank. There are different types of solar batteries you can use in your system. As with any battery, an inverter battery stores energy for future use. However, different batteries will serve different use cases.

Auto batteries, for example, need to provide a considerable amount of current for just a short period to start a car's engine. But inverter batteries are used to provide small amounts of current consistently over extended durations.

The inverter is a crucial piece of a fully functioning off-grid solar power solution. Inverters work by turning the direct current (DC) output collected from your solar panels, into alternating current (AC) - the standard electrical current for commercial appliances.

Inverters play an essential role as the gateway between the photovoltaic solar panel system and the appliances and devices you want to power or recharge. Renogy recommends that you will usually need an inverter for any solar panel that is larger than five watts.

Without using an inverter, there would be no way to convert the power generated by the solar panels into the AC power all our household appliances require for use. The inverter is an essential component of your system, because, without it, a solar panel solution would simply generate power you could never use.

How does an inverter battery work?

An inverter works by converting the DC power generated by the solar panels into AC power that can charge appliances and other electronics.

In an off-grid solar power system, your charge controller will send the solar power to a solar battery bank, and then the inverter will convert the DC to AC for use with home appliances.

Off-grid inverters, which are also known as standalone inverters, will always need a battery bank to function. Many off-grid solar inverters on the market will also include a charger that allows you to replenish the battery.

Any inverter that is larger than 500 watts will need to be hard-wired directly to the battery bank. Whenever you connect an inverter to a battery, you should use an overcurrent protection device between the two devices, such as a fuse or circuit breaker.

AC and DC safety disconnects are also a requirement in all systems. In off-grid solar systems, a DC disconnect should be installed between the battery bank and the inverter. The disconnect is used to switch off the electrical current flowing between the two components. This component is essential for maintenance, troubleshooting, and protection against electrical fires.

Types of Inverters

When it comes to choosing an inverter, different options are available depending on your solar energy setup. A grid-tied system will use either a string inverter or microinverter. Off-grid systems can use either pure sine wave inverters or modified sine wave inverters.

A grid-tied inverter takes power from your solar panels and pushes it into the grid. Grid-tie solar inverters adapt the current from DC to AC and act as the main gateway between your panels and the utility grid.

Off-grid systems require an extra charge controller component to send the solar power to a battery bank before the inverter converts the DC to AC. Standalone solar inverters always need a battery bank to function. Typically, grid-tied inverters will be easier to wire because they have fewer components to work with.

Grid-tied inverters

String Inverters

String inverters are standalone units that are grid-tied and usually installed close to your fuse box. There are usually only one or two string inverters needed for each residential solar panel installation. The low number of components required is one of the main advantages of a string inverter. If the one inverter fails, you will only need to replace one unit. String inverters are a disadvantage if your roof is partially shaded because their electricity output is based upon the worst-performing solar panel.

Microinverters

Microinverters are installed underneath each and every one of the solar panels on your roof. As the name suggests, each microinverter is small, around the size of an internet router. Microinverters are a very efficient option, and unlike string inverters, they take advantage of each solar panel's production capability.

Although they perform better than string inverters, efficiency comes at a cost. Microinverters are typically much more expensive than string inverters because there are more individual components needed.

Off-grid inverters

Pure Sine Wave Inverters

A pure sine wave inverter can produce reliable electricity to operate appliances and electronics without any interference. As its name suggests, pure sine wave inverters produce an electrical current in a pure sine wave shape.

Pure sine wave inverters are both smooth, and quiet and come in varying capacities to match your solar installation and energy needs. Renogy pure sine wave inverters also provide overload protection for both DC input and AC output, this protection helps to prevent damage to the electrical components and the unit.

Modified Sine Wave Inverters

With modified sine wave inverters, the polarity will abruptly switch from positive to negative instead of a true sine wave. These inverters have some drawbacks, as the choppy wave can have a negative effect on more delicate or sensitive electronic equipment. For example, if you want to use solar energy to power medical equipment, such as a CPAP machine, you can't use a modified sine wave inverter.

Additionally, these inverters can be noisy. You can hear a hum coming from devices attached to a modified sine wave inverter in many cases. One of the benefits of using solar power instead of a fuel-powered generator is that solar devices are usually much quieter, so this hum can be annoying.

However, if you just want to use the modified sine wave inverter with simple machines and appliances, it can usually do the job. Modified sine wave inverters are usually the cheaper option of two kinds of inverters, but they have limitations.

Which is the better inverter?

Pure sine wave inverters are usually the safer choice because they can run various everyday appliances and sensitive medical devices. If you want to run machines with AC motors, you will need a pure sine wave inverter.

Electronics and appliances with AC motors include many everyday use items such as microwaves and refrigerators, medical equipment, humidifiers, laser printers, sensitive electronics, laser printers, TVs, and appliances with digital clocks. Your laptop may also work with a modified sine wave inverter.

Modified sine wave inverters are also much less efficient than pure sine wave inverters. Based on their efficiency, versatility, and quietness, pure sine wave inverters are the better choice.

Renogy sells three pure sine wave inverters in 500W, 1000W, and 2000W. Our special LED indicators on the exterior of each Renogy inverter provide you with notifications when the inverter is under or over-voltage, over-temperature, overloaded, or if it short circuits.

Types of Inverter Batteries

Lead-Acid Batteries

Lead-acid batteries have been the standard-bearer of energy storage for a long time. They generate electricity using a chemical reaction between lead, and lead dioxide electrodes dipped in an electrolyte solution.

Lead-acid batteries are, in general, lightweight and economical. The technology is older and reliable. However, they can require maintenance and can release harmful gasses during charging and discharging.

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Maintenance-free batteries

Maintenance-free batteries operate in a similar way to lead acid, but due to having the electrolyte completely absorbed in the separator, there is no requirement to maintain the battery with electrolyte top-ups.

These batteries are as reliable, if not more so than lead-acid batteries. Being sealed, they are much safer and have no battery emissions. The main downside is cost, as they are more expensive to produce.

Tubular batteries

Being newer to the market, these are a more advanced battery construction. As the name suggests, tubular plates are designed for heavy power delivery, which is the general use case for solar panel systems. Being a more bespoke design for these use cases, they are often safer for the environment.

Tubular batteries, by nature of their design, are the most efficient of the three main types. Tubular batteries have a long operational life and require almost no maintenance. Their complex design, which yields these benefits, does come at a cost. The tubular battery can be expensive.

What is the difference between a solar inverter and a regular inverter?

Both solar and inverters and regular inverter batteries provide small, consistent amounts of current over long durations of time. These two types of backup power systems are relatively similar. However, they do have some differences.

Solar inverters work as part of a solar power system to produce green, renewable energy with low emissions. Regular inverters need to utilize either electricity from the power grid or fossil fuels such as gasoline as their primary power source.

UPS Inverter System

A regular home uninterruptible power supply (UPS) inverter system has an inverter and batteries which are hooked up to your home power connection. When electricity is coming from the grid, the UPS charges the batteries using the grid electricity. When the power is off, the inverter will take DC power from the batteries and convert it into AC. An automated switch in the system senses when the grid is no longer supplying power and switches the UPS into battery mode.

Solar Inverter

In an off-grid solar power setup, the batteries are charged using solar panels, but the inverter provides the same function of converting DC to AC. Depending on your needs and lifestyle, the system can be designed to either rely entirely on solar power. Or, it can charge the solar batteries when the sun is available but tap into the grid when sunlight levels are low.

How much does an inverter battery cost?

As with any product, the price of an inverter battery can differ widely based on size and quality. Most inverters will fall in a price range between $150-$800. In the past, off-grid solar power systems were out of reach for many people. The high costs of panels, inverters, and batteries made switching to solar untenable.

Nowadays, battery and inverter prices have dropped considerably, and technologies continue to improve. These advancements make off-grid solar financially accessible for more people.

You can now find an inverter battery at prices as low as $200. Inverters in this price range are usually intended for use with small portable devices. If you plan to use an inverter battery to power all the appliances in your house, you will need a higher-end model. Pure sine wave inverters usually cost between $150 and $900. Inverters can sell for over $10,000 for solutions that are suited to running an entire home off-grid.

Modified sine wave inverters are usually the cheaper option if you're looking to save some money. If you're on a tight budget and only planning on powering simple appliances, modified sine wave inverters could be enough to meet your energy needs. These inverters are cheaper, but they do have some limitations. Remember, they can only be used in simple systems but not with sensitive electronics.

Top Renogy sine wave inverters

1000W 12V Pure Sine Wave Inverter, $189.99

Our 1000W Pure Sine Wave Power Inverter is a top-quality solar power accessory suitable for use in off-grid systems, including cabins and tiny homes. This inverter produces cleaner, smoother, and quieter energy.

This Renogy pure sine wave power inverter is a reliable electricity source to operate fans, tools, lights, and other electronics without interference. Many off-grid solar power systems will require a 12V solar inverter like this model to run everyday electronics.

2000W 12V Pure Sine Wave Inverter Charger w/ LCD Display, $699.99

This 2000W inverter can be used for multiple applications when going off-grid. This pure sine wave inverter can also charge and maintain a solar battery bank when connected to shore power. It is also compatible with Lithium batteries.

The 2000W 12V Pure Sine Wave Inverter Charger has a low transfer time, so your power flow will remain uninterrupted when switching from solar to shore power. You won't need to worry about losing your power access to connected devices and appliances. This model is a perfect backup power source!

48V 3500W Solar Inverter Charger, $899.99

Our 3500W 48V Solar Inverter Charger can almost do it all. This inverter charger combines solar charging, battery inverting, and AC/generator battery charging into one convenient solution. This inverter charger will allow you to take your off-grid system to the hybrid level.

This top-of-the-range solar inverter charger gives you the ultimate control through four user-configurable AC/Solar Charging modes. Three Load Output modes can turn your power system into an uninterruptible power supply (UPS).

This solar inverter charger is a reliable inverter charger that comes with built-in electronic safeguards to protect you and your power system. Equipped with multiple features and modes, the Renogy Solar Inverter Charger is a powerful addition to any 48V battery system!

How to choose the right inverter & battery for your home?

Before buying an inverter for your solar panel system, you will want to do a little homework and make sure you understand the basics. One of the first considerations before buying an inverter is to understand your power requirement.

Your power requirement is the estimated total power consumption of any appliances or electronics you want to power or charge. Some people use portable solar power just to charge small electronics while out camping. Others will power an entire off-grid house with solar, so the requirements can vary widely.

Our solar panel calculator will help you calculate what your power usage is likely to be and compare it to your panels' available sunlight hours and energy output.

Conclusion

If you're looking for a more sustainable lifestyle, then a move to solar power is a great way to get a starter. As installation costs continue to decrease, there is an increase in people considering shifting to solar energy and solar panels.

Understanding how solar energy systems work and all the necessary components will help you choose the best solar panel components or solar panel kits for your desired use case. Whether you're going off-grid, van-living, or building a remote cabin, you can find inverter batteries and all your other solar power needs at Renogy.

Resources

https://medium.com/@alphazee17/difference-between-inverter-batteries-and-auto-batteries-498a332891ae

https://www.luminousindia.com/blog/post/how-to-choose-a-double-battery-inverter-for-your-home.html

https://www.livguard.com/blog/types-of-inverter-batteries-and-their-various-pros-cons/