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How to Charge a Smartphone Battery Without a Charger?

🔄 Updated July 2026 — Refreshed with the latest products, prices, and recommendations.

If there is one facet of today’s smartphones that have had very little innovation since last few years then it has to be a smartphone’s battery. Today’s smartphone has a battery that lasts a little over a day on full charge. Having a power bank is not just a solution. We need to think over ways that can help us get more milliamperes.

We all have been victims of situation where we don’t find a charging slot or are in a deserted place where it is hard to get some battery juice to make that last call on our phone. Let’s look at ways that can help you save your battery and also extend for few more minutes.

Using a battery to charge a battery

  • Remove the battery from the device: Since you will be using another phone’s battery to charge your phone’s battery so the very first step is going to be removing the battery from the old phone. Always remember to be careful. Carefully look for the connection points. Get to know what model phone are you exactly having. You need to figure out as per the android and windows model phone you have as with most of such phones, a slight pressure will remove the back cover and hence the battery. Always make sure removing the battery is not possible with iOS devices as it may cause an explosion.
Find some AA, AAA or 9-volt batteries

There are many utensils and electronic things that have batteries in them which are commonly used in our homes. It is the same battery that is also used in our smartphones and even in cameras.

  • You can think of tons of ways that help charge another battery from the one that you have at home. There is no magic wand that will help you do that almost immediately. As a law of physics rightly states that you can’t get something out of just anything.
  • A basic rule is to always get your batteries charged from some alternating source, attempting a hotwire will lead to nothing. There is a high possibility that you may even damage the whole circuit box. So it is always better than you find an alternating source and get the job done.
    • If you closely look at the rim of most AA batteries, you can clearly see the marking of -ve and +ve sign. In a mobile device, the connector that lies closest to the edge is the one with a +ve charge while the connector which remains far from the edge is usually the -ve connector. In most smartphones, there are three-four connectors and they are usually used for temperature regulation or some other function.
  • A simple smartphone shall require somewhere around 3.7V DC to get charged. The best match for your usual battery is either multiple AA or AAA which are equal to a 9V battery. The one thing which you need to keep in mind is that a simple AA or AAA battery after a day’s usage is equal to around 1.5V each. Since your requirement is around 3.7V so by logic you will still require 3 AA or AAA batteries which needs to be connected in series only after which the cumulative will add up to be 3.7V. Remember you need to have either AA or AAA batteries.
  • Obtain two pieces of metal wire

    • For the purpose of connection, you will be required to get hold of two plastic wires and the plastic over it should be there for the purpose of insulation.
  • Since you will be transferring the power from a normal AA/AAA battery to a smartphone’s battery then the charge will transfer very slowly. At times if you are not doing the process correctly then there are chances that the wires may get little hot. Make sure you are not holding them for long enough as it can harm you.

    Since you will be using AA or AAA to charge your batteries, make sure that the batteries are connected in parallel and only then attach it to the smartphone battery that requires a charge. A thing to keep in mind is that the negative side of the AA/AAA batteries should be connected to the negative side of your smartphone and same with the positive side.

    Method 2: Using the rubbing trick

    Using the rubbing trick

    Rubbing anything produces some energy, like when we rub hands, it produces heat. Similarly, we can look for similar ways to charge our batteries.

    You can continue with the process for either a minute or more. The idea is longer your rub, stronger the charge will be.

    All the discussed ways are just ways to give you few minutes worth of battery to ensure that you use them wisely.


    Other Valuable Resources:

    www.batteriesontheweb.co.uk

    👩
    Katherine Pierce
    Lead Product Reviewer
    Katherine leads product research at ReviewRockers. 5+ years reviewing consumer products with a genuine buyer's perspective.
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