Do Extension Cords Affect Charging Time? (We Checked)

There are several different types of extension cords and cordsets available on the market. The most important thing to know is that they are not all created equal.

When you’re charging your devices, it’s important to get the most out of your cord. This makes sure that your devices are optimally charged.

So what about extension cords? Do they affect the charging time?

In article, I will explain how extension cords affect charging time and factors that affect charging time on deives.

Here’s If Extension Cords Affect Charging Time:

Extension cords will affect charging time. The longer the cord, the less power you can draw from it. This is because there is only a certain amount of watts passing out the outlet. If you use a long extension cord, it will take longer to charge your device because of the watts lost.

A lot of batteries, chargers for smartphones and electrical extension cords with electric devices, screens up, which are charged by them, they lie on a tarp on the grass.

As long as you are using a good quality extension cord, there should be very little difference in charging time. The main thing to consider when using an extension cord is whether or not it is rated for the amperage of your device. This is why cords that come with devices are so short and only allow for 1 or 2 Amps of charging.

The other thing to consider is if your device supports fast charging. If so, then you will want a good quality USB Type-C cable that can deliver up to 3 Amps.

If you’re charging a large device, like a laptop or tablet, then we recommend getting a 15 Amp extension cord which will let you use the full power of your wall charger.

Do Extension Cords Slow Down Phone Chargers?

The short answer is yes. The longer answer is that it depends on the length of the extension cord and how much electricity you’re using.

To illustrate this, let’s look at how a typical extension cord works. An extension cord has three parts:

  1. a female end (the part that plugs into the wall),
  2. a male end (the part that plugs into your device)
  3. and a wire in between. 

When you plug in an extension cord, one of these components will begin to heat up if too much electricity is flowing through it.

In most cases, it’s the female end that becomes hot — especially if you’re charging an iPhone or iPod Touch.

When you plug in an iPhone or iPod Touch, the device immediately begins drawing power from its battery. That’s because it needs energy to boot up and initialize its software.

Once this process is completed and your device is fully functional, it stops drawing power from its own battery and instead draws power from the wall outlet via your extension cord.

If there’s too much resistance in your extension cord, though — such as when you try to charge your device with a very long cable — then the device won’t be able to draw enough power from its outlet and will shut down automatically because of low battery power).

When you plug in your iPhone or iPad, it begins drawing power through the wall adapter and into the device itself.

Keep Notice Of Alerts (iPhone & Android)

If there’s a problem with the wall adapter or if there aren’t enough volts coming out of it, then it might not be able to provide enough power for your device to charge properly.

If that happens, you’ll see an alert message saying that your device isn’t charging properly and may need service from Apple or another company who specializes in repairing phones and tablets.

For smartphones, charging time depends on the battery capacity of the phone.

Let’s take an example of iPhone XS Max, which has a battery capacity of 3,174mAh.

This means that it will take at least 2 hours to charge from 0% to 100% (often longer).

However, if your phone is using a slow charger, then it will take more than 2 hours to charge the phone completely.

If you connect your iPhone XS Max to a 5V/2A AC adapter (a fast charger), then it will take approximately 1 hour and 50 minutes to charge fully.

Can Some Extension Cords Increase Charging Speed?

The short answer is no, not in the way you might think.

The longer answer is that it depends on what kind of cord you’re using and how long it is:

  • First things first: As far as charging speed is concerned, the most important factor is not the cord itself but your charging device. The faster your phone, tablet or other gadget can charge, the faster you’ll get to 100 percent battery life.
  • But there’s another factor at play here: voltage drop. All electrical devices have some resistance to current flow, and when that resistance increases, so does the voltage drop — meaning less power gets from point A to point B.

In home wiring systems this isn’t usually an issue because they’re designed to handle a certain amount of resistance and voltage drop without experiencing any problems.

But if a device has a lot of resistance (like some older appliances do) or if there’s a lot of distance between points A and B (like with extension cords), then voltage drop becomes an issue — and that’s what causes slow charging speeds.

Read our blog here about do extension cords reduce power?

What Factors Affect Charging Speed?

The charging speed of your smartphone depends on many factors:

  • The Battery Capacity: The higher the battery capacity, the longer it takes to charge a device. For example, a smartphone with a 3000mAh battery will take longer to charge than a smartphone with a 5000mAh battery.
  • The Charger: The charger that you are using also impacts on charging speed. If you are using a low quality charger then the charging speed will be slow. On the other hand, if you are using an original charger from your smartphone manufacturer then the charging speed would be fast.
  • The Device: The device that you are using also affects charging speed. For example, if you are using an iPhone and try to charge it with an Android phone charger then there will be no change in charging speed but is if you use an iPhone charger then there would be some change in charging speed. This because Apple uses adaptive fast charging technology and Android phones do not have this feature so they take more time to charge when plugged into an Apple phone charger compared to when they are plugged into their own wall chargers or car chargers which have adaptive fast charging technology built-in them.
  • Charge Rate: The current (Amps) and voltage (Voltage) of your device determine its charge rate. This is measured in mAh (milliampere hour). The higher the mAh rating, the longer it will take to fully charge your device. For example, an iPhone 6 has a 1,810mAh battery while an iPhone 7 has a 1,960mAh battery. That means it will take more time to charge an iPhone 6 compared to an iPhone 7 because it has less capacity.
  • Charging Technology: The charging technology used in smartphones also affects how fast they will charge. Fast charging technologies such as Quick Charge 3.0 and Adaptive Fast Charging allow you to get up to 50% battery life after just 30 minutes of charging with compatible chargers and cables that support these features.

Should You Plug Phones and Laptop Chargers into Sockets for Fast Charging?

Your phone doesn’t know if it’s being charged by a computer or an AC plug-in charger — it just recognizes the voltage being supplied by whatever it’s plugged into (usually 5 volts).

If you plug your phone into an extension cord with multiple outlets, then each outlet will be supplying different amounts of power (depending on how many other devices are plugged in).

This means that some of those outlets will supply less than 5 volts while others may give more than 5 volts.

Most chargers are also smart enough to slow down or stop charging when they’re full — a feature called “automatic voltage regulation.” This prevents damage to your devices by preventing overcharging and overheating.

Can Extension Cords Wear Out Over Time and Change Charging Speed?

The short answer is yes — but not by much.

If there’s no resistance in the path between two points — like when there’s no wire connecting them — then electrons will travel freely from one end to another without having to go around anything else first.

The cord itself can become damaged over time from repeated bending or twisting. This can cause the wires inside the cord to break down and fray at the ends.

When this happens, you might notice that your phone charges slower than normal. The same problem could happen with other devices that plug into electricity through a cord like lamps or fans.

You should ALWAYS throw out extension cords and power strips if they are getting hot or look worn!

Why Does an Extension Cord Affect the Charging Time?

It’s possible that you have a faulty cable or power adapter, but it’s also possible that your device is not compatible with the voltage provided by your extension cord.

If you’re using a MacBook Pro or other laptop that requires a specific voltage for charging, for example, using a lower-voltage extension cord could cause it to take longer to charge.

Apple says its 12W USB Power Adapter and 29W USB-C Power Adapter can be used with any USB-C enabled device that supports charging over USB-C in addition to Apple’s own Lightning cables.

However, it warns against using third-party chargers because they may not deliver enough power or may even damage your device.

Similarly, the company recommends against using third-party Lightning cables with its devices because they may not be certified safe by Apple. For example, if you connect your iPhone XS or XR to a Lightning cable from an unofficial manufacturer instead of Apple’s official cable, there’s no guarantee that it won’t damage your phone — even if it appears functional at first glance.


Many people believe that the longer an extension cord, the longer your charging speed will be. However, this is true but the drop is very small, in most cases.

The real reason for slow charging speeds is voltage drop, which is caused by the power supply being unable to deliver enough juice to your device at all times.

Read our blog about can I leave chargers plugged in all the time?


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