How to Charge A Phone With a 9V Battery (Ultimate Guide)

In this article, I will show you how to charge your phone with a 9v battery with several different methods you can choose from.

While you may have heard of charging your phone with a lemon or potato, what if I told you that you could charge your phone with a battery. 

This means that you don’t need to bring a big portable battery anymore. The good news is that it is true. It’s a hack that will get you out of a pinch oftentimes.

My favorite way to charge a cell phone with a battery is to use a USB converter to charge a phone with a 9V battery. Most electronics shops carry this item, which enables you to connect your phone’s charging cable to the converter, which is then linked to the 9V battery. It’s essential to keep in mind that a 9V battery may not have the power to completely charge a phone, and it could not be as effective as charging through a phone charger or a computer USB connection.

Let’s dig into more detail.

Materials to make the big portable battery
  1. Car charger
  2. Metal Spring/Copper wire (can be from a pen)
  3. Charging cable
  4. Some duct tape (masking tape or normal tape works as well)
  5. Aluminum Foil (just in case)
  6. A key (for method 1)

Method #1

The first thing you must use is a car charger – the kind that plugs into any car. To unlock the insides of the battery charger (the stuff you are going to use), use a key, metal pen, spring, or copper wire to attach the metal nub on the side of the charger. 

Install the 9-volt battery so that the big negative terminal is on the spring as well as the smaller positive end is on the car charger. 

Pinch and keep it in place for several minutes, and there you have it! Your iPhone or Android device is charged up. You should double-check that everything is attached – the spring should be hitting the car charger’s nub, and the car charger button should be pressed in. 

It will not work if any of the parts are not properly paired. To keep these parts in place, wrap them in a piece of aluminum foil.

Method #2

Take a 9- volt battery with the negative side connected to a black insulated wire and the positive side connected to a red insulated wire. Attach the other end of those wires to the car charger’s right and left sides, where the USB was connected.

Method #3

Finished battery product with the spring

Place the 9-volt battery so that the negative (bigger) terminal is on the spring and the positive (smaller) terminal is touching the button in the center of the car charger. Hold it in place and wait as your phone charges.

Safety Precautions

To show caution and show crutial water and plastic bag

The car charger can regulate how much current goes into the phone, which means it allows only up to 5 volts of charge. But experts advise that this method should only be used for emergency purposes. 

The method could short the battery and cause an explosion, damaging your phone and risking injury to yourself. So the next time you find yourself in a sticky situation with a dead cell phone, remember that you can use this smart technique to put a bit of quick charge into your device and impress your friends. 

Keep in mind though, that a quick 9-volt battery charge should only be used in very important situations when you have no other power supply.

What To Do Next

Man lost in the woods and calling for help

If you don’t have these materials readily available to you, you should resort to creating other types of signals to call for help. 

In our other articles about creating fire in the wild, you can create smoke signals to help call for rescuers.

Additionally, other types of signals include audio signals. If you didn’t know already, your voice will only help you shout for so long. It can’t reach very far unless you are already close to a road or residential area.

This is where a whistle would come in very handy. Blow the whistle three times at equal intervals, equivalent to a firefighter’s call. The cycles differ, but they should be about 30 seconds. 

Each blow should last approximately 5 seconds. Wait a few moments before blowing the whistle three times. Rescuers in the area can view this as a distress call for assistance. If you don’t have a whistle on you, there are other ways to whistle, like whistling with your hands. We haven’t covered this yet, but we will in the future. 

Yelling and blowing whistles are not the only ways to send audio signals. The sound of a gunshot may also be used. Simply shoot your weapons three times in a row, as if you were blowing a whistle. If you don’t have a gun or a whistle, you can still signal for help by hitting a dry log three times with a stick at regular intervals. 

Dry logs are notorious for making loud cracking noises that can be heard for miles. You’ll get some support shortly with these methods.


How much will your phone charge with this hack?

Phone plugged into a charger

Although a standard 9-volt battery has only 500 milliAmpere hours (mAh), most mobile phones now require thousands of mAh to bring it to full charge which will take more than a few minutes. 

For example, an iPhone 7 requires approximately 1,960 mAh, while a Samsung Galaxy S8 or S9 can be completely charged with as little as 3,000 mAh. (Newer phone models will be different) 

A 9-volt battery will give you a little bit of charge to call 911, text your parents, or request emergency assistance. However, though you can receive some charge from the battery, getting to a maximum charge in this manner is not the most realistic (or safest) option if you have available electricity.

Big portable battery to demonstrate other alternatives

Of course, having this plan in case of an emergency is helpful, particularly when planning for a disaster such as a looming storm. Keep a few 9-volt batteries around the property, as well as a pen with a spring inside. 

It’s is an even better choice if you have a large portable battery. Just make sure it’s at full charge. 

In case you want to know how long it will take to charge your phone up to the full battery, it would take around 6 to 8, 9-volt batteries to fully charge your phone so this clearly isn’t supposed to be for the long-term.

What should I do if it doesn’t work?

Cell phone battery full charge debugging

To begin with, double-check that everything is linked. The spring should be in contact with the metal of the car charger’s side nub, the button on the side of the charger (the battery’s positive side) should be pressed in, and your charger cable should be connected as usual. 

If some of these pieces aren’t staying in place, use a strip of aluminum foil to close any gaps. 

On a big phone with a quick charger, the 9-volt battery can struggle to supply enough voltage under load, potentially causing the charger to start and stop constantly.

What should I do if I don’t have a metal spring or a ballpoint pen?

If you refer to methods two and three, we explain another method that doesn’t require you to have a metal spring or a ballpoint pen because those methods without a spring use materials that are within the car charger or are different.

Have you personally tried this in a sticky situation?

I have actually used this in a couple of scenarios. On a few hiking trips and a few camping trips, I realized that my phone was dead. It gave me a little bit of charge within minutes which allowed me to find some way to call my family members, look for other trails and landmarks, and open my GPS. I used the quick charging method and was able to charge up my phone and use it again. I also know a lot of friends and relatives who also use this nifty trick as well in the wild and even at the airport.

How would this trick even be practical at home?

Shows the potential for a power outage with many types of natural disasters

Well, first of all, you could easily use this trick if you have a power outage or if there is a major natural disaster. A great example of this was in Texas not too long ago. They had a major snowstorm and a lot of their power and electricity got cut off. People who would’ve known this method would’ve been able to charge their phones and get contact other people. Second of all, you should always be preparing for the worst. Texans didn’t even think that there was going to be a snowstorm because they have never even seen snow in so long so they weren’t even prepared.

Does this trick work with other smartphones like Motorolla and Samsung?

Yes, of course. As long as the charger cord is able to be plugged into the car charger, this method should work with any smartphone, and for that reason, this method is very practical.

How should I signal for help?

Aside from audio signals and just calling for help, you can also learn morse code. Morse code can be very practical in everyday situations and one day might save your life if you learn it.

How is this method even practical if I have to use 6, 9-volt batteries just to charge my phone to max charge?

This method isn’t supposed to be used for playing flappy birds or angry birds in the wild. This method is for emergency scenarios when people need that extra 10 or 20% to call for support and rescuers. 

It isn’t supposed to be used for fast charging your phone to 100% and going on Instagram. A big portable battery could work for that.

Final Thoughts

Best wishes on building your charger using a 9-volt battery we talked about! 

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