Brownout Vs. Blackout: What’s the Difference

Brownout Vs. Blackout: What’s the Difference

R
Renogy
Oct 27th 2024

In the United States, an average of more than four  power outages per year brings us face to face with the reality that the power supply is not always stable. When we talk about power failures, we typically encounter two technical terms: brownout vs. blackout.

While these two terms are often used interchangeably, they represent very different situations. According to statistics, more than 60 percent of U.S. households have experienced at least one unstable voltage or total power outage in the past year. From an office computer suddenly shutting down to a home's air conditioner losing its cooling effect, these can all be signs of a brownout or blackout. And in this age of heavy reliance on electricity, it's become especially important to understand the difference between these two situations and how to prevent and respond to them with backup power.

What is a Brownout?

A brownout is a temporary drop in voltage in an electrical power supply, resulting in dimmed or flickering lights and reduced performance of electrical devices. Unlike a complete power loss, during a brownout your electrical devices still receive power, but at a reduced voltage - typically 10-25% below normal levels - which can cause them to function improperly or at reduced capacity.

Brownouts typically have minimal effect on heat and lighting because most of these can function reliably for short periods on low voltage. However, sensitive electronics like TVs, computers, and gaming consoles won’t be able to function during a brownout.

What is a Blackout?

A blackout is a complete loss of electrical power in a specific area, where the power supply is entirely cut off and all electrical devices cease to function. During a blackout, there is zero electricity available from the power grid, affecting everything from lighting to appliances, and it can last anywhere from a few minutes to several days depending on the cause and severity of the outage.

Blackouts often come without warning and last for unstipulated periods. But in some cases, blackouts could be pre-planned by the energy company as a precaution or to fix a fault on the line. These are called planned outages. They typically occur with some warning and have a pre-defined timeline.

What are the differences between blackout and brownout?

Having understood the basic concepts of brownout and blackout, let's dive into the key differences between them. While both types of power failures can affect our daily lives, they differ significantly in their nature, scope and severity.

Severity

While a blackout represents a complete interruption of power supply where no electricity flows through the system at all, a brownout is characterized by a partial reduction in system voltage. During a brownout, your electrical system still functions but at a reduced capacity - typically 10-25% below normal voltage levels. Think of a blackout as turning off a light switch completely, whereas a brownout is like using a dimmer switch to lower the brightness.

Impact

During a blackout, all electrical devices simply shut down unless connected to a backup power source. In contrast, during a brownout, devices continue to operate but may exhibit unusual behavior. Lights dim, motors run slower, and some sensitive electronics might malfunction or perform erratically.

This partial power state can actually be more damaging to certain equipment than a complete shutdown, especially for devices with motors or sensitive electronic components.

Duration

Blackouts tend to be more straightforward in their resolution - power is either restored completely or remains off, and they can last from minutes to several days depending on the cause. Brownouts, however, are often intentionally implemented by utility companies as a voltage reduction strategy and typically last for shorter, predetermined periods. They may occur regularly during peak usage times as a load-shedding technique.

Symptoms

A blackout's effects are immediately obvious and unmistakable - everything goes dark. Brownouts can be more subtle and might go unnoticed initially, except for slightly dimmer lights or slower-running appliances. This subtle nature of brownouts can make them more dangerous, as users might continue to operate sensitive equipment without realizing they're receiving inadequate power.

Causes

Blackouts are usually unplanned events caused by severe weather, equipment failure, or accidents. Brownouts, on the other hand, are often deliberately implemented by power companies as a way to manage grid demand during peak usage periods. This controlled reduction in voltage helps prevent a complete system failure that would result in a blackout.

Recovery

Recovering from a blackout typically involves repairing damaged infrastructure or resolving the root cause before restoring full power all at once. Brownout recovery is usually more gradual, with voltage being incrementally increased to normal levels to prevent sudden power surges. This controlled restoration process helps protect both the grid and connected devices.

Knowing the difference between brownout and blackout makes it especially important to take the proper precautions. According to the Federal Emergency Management Agency (FEMA), more than 60 percent of U.S. households don't have a complete emergency plan for a power outage, which makes them especially vulnerable in the face of a power failure. Let's take a look at how to prepare for these two different types of power failures.

How to Prepare for a Brownout

Preparation for brownout focuses more on protecting electronic equipment. Installing a high-quality voltage regulator is the most basic protective measure, which ensures that the equipment can still operate stably when the voltage fluctuates. For sensitive equipment such as computers and servers, it is recommended to equip a UPS with a voltage regulator that automatically switches to battery-powered mode when the voltage is unstable.

In addition, it is also important to develop good power habits: when you know that brownout may occur, take the initiative to turn off or unplug unnecessary high-power electrical appliances, and set the air conditioning to a higher temperature, which not only protects the equipment, but also helps to reduce the burden on the power grid. In office environments, consider enabling energy-saving modes on laptops and saving important documents in a timely manner to prevent data loss due to voltage fluctuations.

How to Prepare for a Blackout

In the event of a blackout, the first thing to do is to reach out to your utility service provider and inform them. Most of these have toll-free numbers on which you can call and let them know of your problem. Some also can be reached via WhatsApp while others have a dedicated mobile app.

Reaching out will help you determine how long it will take before power is restored. This should ease your planning phase. Also, it could speed up the restoration process especially when disruption is not the routine rolling blackout or power outage done by the energy company.

Use Alternatives for the Meantime

If you need to cook a meal, gas is the best alternative during a blackout. Most electrical ovens manufactured today have burners that use gas. For lighting, you can use flashlights and rechargeable lamps. These can give you somewhere between 5-8 hours depending on their battery capacity.

Turn to Power Backup Sources

Having a power backup source like a power station or generator is an efficient way to tackle blackouts. This way you can switch all the appliances you want to use as you wait out the blackout. There are several power stations sold on the market today. These are basically high-capacity battery packs in a compact and portable format. Most of these can power a variety of devices like TVs, computers, air conditioners, and electric grills. However, it’s worth noting that the more applications you can use for one, the steeper the price. A 256Wh power station could power a TV for 2-7 hours, depending on its capacity.

Generators are a bit different but are just as effective. Most mid-sized generators use petrol or propane to generate electricity. However, industrial backup generators use diesel. These are much stronger and can an office building run for several hours depending on the number of applications.

Use Power Alternatives like Solar PV and Battery System

For long-term power security, A  solar photovoltaic (PV) and battery system is an excellent alternative. By converting sunlight into electricity and storing it in batteries via solar modules, basic power needs can be maintained even during power cuts. We recommend choosing the right backup power system for your scenario.

For home users, the  Renogy 600W 12V Universal Off-Grid Solar Kit is especially recommended, a system that meets basic household electricity needs, including lighting, charging appliances and powering small household devices. Even during power outages, it will continue to provide you with clean energy as long as there is sunlight.

For frequent outdoor activities such as 4x4 off-roading, small RV camping, or boat fishing scenarios, the  Renogy Core Mini Li-ion battery is a smarter choice. This compact portable power supply delivers up to 300A of current in less than 5 seconds, making it easy to power high start-up current devices such as refrigerators and microwave ovens, while its unique metal battery spacer retention system ensures stable performance over bumpy roads.

Final Thoughts

Regardless of whether it’s a brownout or blackout, power disruptions can be a party pooper. Hopefully, our article has given you enough insight on how to tell the two apart and how to prepare for each scenario. Following these few guidelines will help protect your appliances and will also help you navigate the challenges that blackouts and brownouts bring.

Brownouts Vs. Blackouts FAQs

1. How long do blackouts typically last, and how should I prepare?

Typical blackouts last around 4 hours, though they can extend for days depending on the cause. Essential preparation includes storing drinking water (1 gallon per person daily), non-perishable food, flashlights, backup batteries, and a reliable power backup solution like solar kits for homes or portable power stations for outdoor scenarios.

2. How can I tell if I'm experiencing a brownout or a blackout?

The key difference lies in the power availability. During a blackout, all electrical devices stop working completely due to total power loss. In contrast, a brownout is characterized by dimming lights and reduced performance of appliances while still functioning. An effective way to confirm is using a voltage meter - brownouts show reduced voltage (10-25% below normal), while blackouts register zero voltage.

3. Can brownouts damage my appliances?

Brownouts pose a significant risk to electrical devices, particularly those with motors or sensitive electronics. During low voltage conditions, appliances draw more current to maintain operation, potentially leading to overheating and damage. That's why it's crucial to either power down sensitive equipment or protect them with voltage regulators during brownout events.

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