Keeping your phone charged during a storm is essential but what happens when the power goes out? According to the Sun Sentinel, millions of people are expected to be without electricity "for weeks" after Hurricane Irma hits Florida.

That means there will be no way to charge your smartphone. Even a portable charger will lose charge after several uses. However, there is a simple hack that could turn out to be a lifesaver.

Keep your phone charged during Hurricane Irma

If you lose power during the hurricane, chances are you will not have an internet connection.

A mobile hotspot will come in handy, but it may not work if nearby cell phone towers are knocked out by the storm. However, without internet access, a fully-charged phone is essential.

During (and after) Hurricane Irma it's important to have your phone available to make calls to friends, family, and emergency services. Keep your phone charged without electricity by following the instructions. We've also included a video to confirm this hack really works.

Stock up on 9-volt batteries

When you are stocking up on storm supplies, but a few 9-volt batteries. You will need one to charge your iPhone or Android mobile device, a house key, and a portable car charger — the kind that goes into the lighter socket in your car.

Both items are relatively inexpensive and normally available at convenience stores if you local Walmart or Target is sold out. Keep all three items in a zippered plastic bag so you have everything handy when you need to charge your device.

Using the step-by-step instructions in the video below will show you how to recharge your mobile phone in minutes.

Don't expect a full charge right away, but you will get enough power to get your phone back on so you can make a call or, if you have service, send a text.

Step-by-step instructions

Here's how to get your phone back on while the power is out.

  • Connect a phone charging cord to the portable car charger.
  • Place the pointed end of a house key into the negative battery terminal.
  • Press the metal of the car charger into the positive terminal on the battery.
  • Once you make the connection, your phone should start charging right away.

Granted, it's tough to hold both the charger and the key in place for a long period of time, but this hack is a quick fix while you're without power. Considering some Florida residents could be without power for days or weeks, the 9-volt battery charger will come in handy.

Check out the video below to see exactly how the process works.