You Can Actually Charge Your Phone With a 9-Volt Battery
In a power outage, a 9-volt battery can give your phone enough power to make a call or send multiple text messages. You may have seen this trick before , but it works especially well with this option when you use the spring from the handle to connect the negative terminal.
You will need a car charger – one that you plug into what was formerly called a cigarette lighter in your car. Just take the spring from the handle and glue it to the small metal tab on the side of the charger, as shown in the photo above.
Next, align your 9-volt battery so that the large (negative) battery terminal is on the spring and the positive (smaller) terminal contacts the button in the center of the car charger.
Then just hold it in place. For a while.
How much time will it take?
It took me 7 minutes to charge the iPhone SE from 60 percent to 67 percent. The exact time may vary depending on how charged your phone is and how much power is left in the 9-volt voltage.
Your hands might get tired, but you can suggest MacGuyver your own solution for this part: perhaps tape the battery to the charger, or wedge the whole device between heavy books and a wall.
How much will I receive?
A typical 9-volt battery has 500 milliampere-hours (mAh) . Compare that to the size of your phone’s battery. A few examples:
- iPhone 8: 1821mAh
- iPhone 7: 1960mAh
- iPhone SE: 1624mAh (this is the phone I tested)
- Galaxy S8 or S9: 3000mAh
- Pixel 2: 2700mAh
It will take four 9V batteries to fully charge my little phone, and six for the Galaxy S9. So it’s not a long-term solution, but it might give you a small fee to text your mom, or order Lyft, or call 911 if needed.
What if it doesn’t work?
Make sure everything is connected first. The spring should touch the metal of the side tab of the car charger, you may need to press the button on the end of the car charger (positive pole) and the charging cable should be connected as usual.
If you are having trouble holding any of these parts in place, use a piece of aluminum foil to cover any gaps.
On a large phone with a fast charger, the 9V battery may not supply enough voltage under load, and the charger may start and stop repeatedly. This is not confirmed, but this is the theory my husband had when we tested this hack on his Moto X Pure and Qualcomm 2 fast charger. So we added two AA batteries to the circuit. I used aluminum foil balls to help the batteries connect and glued them in place. ( Make sure the pieces of foil don’t touch each other! You don’t want a short circuit!)
With just 9 volts of voltage, his phone dropped from 77 percent to 76 percent in five minutes of attempting to charge. But a little later, when it was 75 percent, I was able to charge it to 77 percent in five minutes with the extra batteries.
So if you’re gearing up for a storm, grab some 9 volt batteries and make sure you have a spring-loaded handle that you can use. (As a last resort, you can replace the spring with a piece of folded aluminum foil, but the spring is very convenient.)
However, it’s even better if you just buy a large portable battery for your phone and make sure it’s charged before the storm hits. Don’t forget that if you have an old laptop, even if its screen is broken or there are other problems, you can charge it and unplug the phone from the USB ports.