How Many Watts Does a Phone Charger Use

In today's digitally driven world, mobile phones have become an indispensable part of our daily lives, making phone chargers equally essential.

However, amidst growing concerns over energy consumption and its impact on our bills and the environment, it's important to understand how much electricity these small but vital devices consume.

Published: February 22, 2024.

Understanding Watts

Before diving into the specifics of phone chargers, it's crucial to understand the unit of measurement used to quantify their power usage - watts (W). A watt is a unit of power that measures the rate of energy transfer.

In the context of phone chargers, it indicates the amount of electricity the charger is capable of supplying to the phone's battery within a given timeframe.

Average Power Usage

The wattage of phone chargers can vary significantly depending on the type of phone, the charger's design, and the charging technology it employs. On average, modern smartphone chargers are rated between 5 to 25 watts. Standard chargers that come with most smartphones typically have a power output of around 5 watts, which is sufficient for a slow but steady charging process.

With the advent of fast charging technology, the power output of chargers has significantly increased. Fast chargers can offer outputs ranging from 18 watts to over 25 watts, enabling quicker charging times by delivering more power to the phone's battery.

For example, a 20-watt charger can charge a phone much faster than a standard 5-watt charger, given the phone supports fast charging.

Standby Power Consumption

An aspect often overlooked when discussing charger power usage is the energy consumed when the charger is plugged in but not in use, commonly referred to as "vampire" or standby power. Even when disconnected from the phone, a charger can continue to draw a small amount of power.

This consumption is relatively minimal, typically less than 0.5 watts (usually 0.1 to 0.5W), but it can add up over time, contributing to energy waste and slightly higher electricity bills.

Energy Standby Consumption:

Here is an example of how much energy and money one phone charger "burns" during a year if it is not unplugged from the wall after charging.

Let's assume:

• standby consumption 0.3W
• charger use: every second day for 3 hours.
• energy price: $0.15 per kWh.

On the days when the charger is not in use, it consumes (24h of standby mode):

E (kWh) = 0.3W * 24h / 1000 = 0.0072 kWh

On the days when the charger is in use, it consumes (21h of standby):

E (kWh) = 0.3W * 21h / 1000 = 0.0063 kWh

On a monthly basis, that is:

E (kWh) = 15 * (0.0072 + 0.0063) kWh = 0.2025 kWh

And on a yearly basis, that is:

E (kWh) = 12 * 0.2024 kWh = 2.43 kWh → $US = 2.43 kWh * 0.15 $/kWh = $0.3645

So, if we keep the charger plugged year long, it will annually consume ~2.43 kWh of energy, which is ~$0.37.

Obviously, this is not much; after all, it is a single charger. But, an average American has 3.5-4.0(!) phone chargers.

If there are 300000000 (3 * 10⁸) phone chargers in standby mode only in the US, that would be annually:

E (kWh) = 300000000 * 2.43 kWh = 729000000 kWh → $US = 729000000 kWh * 0.15 $/kWh = $109350000

So, having 300 million chargers constantly plugged in would cost ~100 million $US a year.

Factors Influencing Power Usage

Several factors can influence the power consumption of phone chargers, including:

• Charging Technology: Fast charging technologies consume more power to reduce charging times.
• Phone Battery Capacity: Larger batteries require more energy to charge fully, potentially increasing the wattage required from the charger.
• Charger Efficiency: Not all chargers are created equal. Some are designed to be more energy-efficient, converting electricity into battery power with minimal loss.
• Usage During Charging: Using the phone while it's charging can increase power consumption as the phone has to power its operations and charge the battery simultaneously.

Few Examples:

Here are a few examples of smartphone batteries and their respective chargers:

• Samsung S24 Ultra: 5000 mAh, 45W wired, 15W wireless,
• iPhone 14 Pro Max: 4323 mAh, 20W wired,
• iPhone 15 Plus: 4383 mAh, 20W wired, 15W wireless,
• iPhone 15 Pro: 3274 mAh, 27W wired, 15W wireless,
• Google Pixel 8 Pro: 5050 mAh, 30W wired, 23W wireless (2nd-gen Pixel Stand), 12W wireless (Qi).

How to Charge Phone During Blackouts, Emergencies, or When Being Off-the-Grid

There are several very simple methods of charging phones during emergencies, blackouts, or when being off-the-grid:

• Power Banks: A fully charged power bank can be used to charge the phone. Simply connect them with a charging cable and let the power bank do its task - charging speed depends on the model of the phone and the charging technology built into the power bank.
• Power Inverters: Connect large capacity, deep cycle battery to the power inverter and connect the phone charger to the AC outputs of the power inverter. Let the charger charge the phone as it normally would.
• Power Generators: If the power generator is an inverter power generator with very low THD (Total Harmonic Distortions) levels (below 3%, for example), it can be used to directly power the phone charger - plug the charger into an AC output of the generator and let the charger do its task.

Note: running a power generator just to power a single phone charger is not an energy/fuel efficient method of using power generators.

• Solar Generators/Power Stations: Plug the charger into the AC outlet of the solar generator and charge the phone. Simple as that. Just be sure that there is enough energy stored in the solar generator battery.

Few Final Words

Understanding the wattage of phone chargers is key to gauging their impact on your electricity bill and the environment.

While the energy consumption of individual chargers is relatively low, especially when compared to larger household appliances, promoting efficient charging habits and unplugging chargers when not in use can contribute to energy conservation.

As technology advances, we can anticipate further improvements in charger efficiency, reducing their environmental footprint while keeping our devices powered and ready to use.