Is it Possible to Charge a Spare Battery without the Phone?

One of the most in-demand questions that people have today is: is it possible to charge a spare battery without the phone? There are several reasons why someone would want to do this, but there are also some limitations. In this blog post, we will tackle whether or not it's possible to charge a spare battery without a phone and what you should consider when making your decision.

Is it possible to charge a spare battery without the phone?

As the demand for mobile technology continues to increase, it's no surprise that the battery life of these devices is decreasing. To keep up with these demands, some people have invested in a spare battery for their phones. They might be using it as a backup, or they might not like to use the same one every day.

With a spare battery on hand comes the thought of whether or not it's possible to charge it without a phone. This is doable, but there are limitations to consider.

Charging spare battery with a portable external charger:

Some people opted to purchase portable battery chargers to keep the batteries topped up and ready to use. This allows them to charge the spare battery without a phone, and then they can just plug it into their device when needed.

There are some drawbacks, though as in most cases, it is not advisable. In fact, if you check with your manufacturer, they will tell you that doing this may cause damage to your device and may void the warranty. You would have to consider if using a portable charger is safe. By using a portable charger could pose a risk of serious damage to the battery. It may possibly output a voltage above or below what your phone demands. If you charge your phone with the incorrect voltage, you may risk permanently damaging the battery.

There may be high-quality portable chargers available from a reputable company that they say are efficient and will protect your device from overcharging or overheating. It is still best that you do thorough research before using this method to charge your spare battery. It will help if you get your manufacturer's recommendation before you do so.

Can you charge a spare battery with a USB cable?

You could also charge your spare battery with a USB cable. However, this method is not completely recommendable and can only be used when you do not have any other option or during an emergency situation. The process of charging the spare battery with a USB cable might be complex and time-consuming. Some have tried this method and were successful, but it may not be the best option to use.

-This method will require you to find an old USB cable.

-You will need to peel off one end of the USB cable to expose the four color-coded wires. Find the black and red wires as these are the ones you will need for this project. You may find a different color of wires to some cheaper USB cables, and these would be in pink and blue wires.

-You will then peel off the red and black wires to expose the actual metal wires.

-Grab your battery and locate the four metal slots on it, also known as the battery terminals. Both ends of these metal slots are labeled with positive (+) and negative (-) signs, which will serve as your guide.

Carefully attach the red wire to the battery's positive terminal and the black wire to the negative terminal. You may use electrical tape to fix the wires on the battery terminal.

-Plug the other end of the USB cable into your PC and allow it to charge for 15-20 minutes before disconnecting the USB cable. Once charging is done, you should be able to use your phone with a recharged battery.

Is it safe to charge the battery with a USB cable?

As mentioned earlier, this should be done only in an emergency situation, and there's no other option available. It may be safe if you have done it before and you are aware of the possible risks and as long as you know how to do it. In this method, the USB cable will provide a voltage a bit higher than the required voltage to charge the battery. However, if you are not aware of how much voltage is required to charge your device's spare battery, it may be a risk that it will damage other components in your phone or even explode. If you opt to perform this method, be sure to charge the battery no more than 15-20mins.


Keeping your phone's battery in good condition is a must, not just for convenience but also to prolong its life. However, there are times that you need to take it out of your phone and charge the spare battery separately from your main power source. Fortunately, since most people carry their chargers with them at all times as part of their daily routine or because they're obsessed with keeping their phones charged, it is possible to keep your spare battery ready for use at all times. I hope the guides above can help you keep your phone's battery in good condition and ensure that it is ready to use when the time comes.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.