Lithium Battery Won't Charge – Introduction, Jumpstarting, and Recharging

May 12, 2022   Pageview:85

Cordless power tools have taken the world by storm. We have become so dependent on them that it's hard to imagine where the world would be without them. What makes these devices more useful is the rechargeable batteries they use.

It becomes difficult to use when the battery can no longer hold power. A dead battery is useless, and many users will often rush to find a new battery.

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You may not know that a dead battery is not completely dead. This means you can reuse it if you know what to do.

Today, we shall be sharing a few ways of dealing with a lithium battery that won't charge. But first, you need to know what is happening with the battery. It's important to establish whether it's completely 'dead' or you can still get some juice from it.

How to Jumpstart a Dead lithium-ion battery?

Perhaps you have already seen how people jumpstart a dead car battery. The same thing can happen with a lithium battery. You will need a good battery to boost the dead one in both cases.


Jumpstarting a lithium-ion battery is not rocket science. You will need the following tools.

A flat-end screwdriver. Pick several differently sized screwdrivers depending on the batteries you are working with.

Spudger. You can use a metal or plastic one – for separating the cases.

Side cutters or flush cutters. You need this for cutting the battery or thick tabs and wires.

A multimeter. Measuring the voltage is an important step of this process.

Safety gear. Make sure you have gloves and other protective gear.

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Jumpstarting a lithium battery at Home

You can easily jumpstart a dead battery at home. Apart from the tools above, you will need a fully charged battery. It will help you to jumpstart the dead one.

Method 1:

Follow these steps:

Step 1: Connecting the Wires

Take two short and insulated wires and use them to connect the batteries. Be sure to connect the matching polarities between these batteries.

Connect the negative end of the dead battery to the negative end of the charged battery. Connect the positive sides too.

This step lets you transfer the power from a live battery to the dead one.

Step 2: Disconnect the batteries.

Wait for about five minutes and then disconnect the wires. You will have set the battery in the right setup for proper charging.

Step 3: Charge Normally.

?Place the dead battery in the right charger. Notice what happens next. If it starts to gain charge, the jumpstarting process has worked. Leave it to charge for around an hour until you get a full charge.

If the battery refuses to charge, try jumpstarting again. If it still does not charge, it's probably beyond help, and you will need a new one.

Method 2: Increase the voltage.

You can also jumpstart a dead li-ion battery by increasing the voltage on your charger. You must understand that lithium batteries die when left uncharged for long.

This step is risky. The idea is to overcharge the battery. But if you overdo it, you may cause it to explode. So, before trying this, ensure you put on protective gear, including goggles. Work from a large open area.

Next, cut two-wire pieces. One battery works as the positive wire, and the other will be negative. Remove the protective coating from both ends.

Put one end of the positive wire into the positive pinout of the battery. Insert the negative side into the negative port of the battery.

Leave the battery for two hours. Before disconnecting this setup, take care to avoid the risk of explosion. Once you finish the process, reinsert the battery and confirm if the jumpstart process was successful.


Method 3: Replace cells in the battery.

Sometimes the biggest issue could be the old battery may have bad cells. If you have an unused battery that still works, use its cells.

Using a knife and a flat head screwdriver, try opening the casing on the battery. You will see several cells arranged individually. Each cell is connected to the circuit board via wires in a battery pack. The multimeter will come in handy to ensure there is no residual charge.

You will need to separate the cells carefully from the wires. A soldering tool should be used here. Use the same tool to solder the new cells together and then reset the wires.

Restore the casing and leave the battery to rest for at least 48 hours. This ensures the soldering worked. You can then try and see if the process worked.

How to Recharge a Dead Lithium Battery?

To recharge a dead lithium battery, you will need:

Safety goggles

A li-ion battery charger

A multimeter

A USB cable

Crocodile clips

A stable power source

You will need to put on safety goggles and other gear before you start. Safety is very crucial because juicing a dead battery can cause serious damage.

Take the voltage of the dead battery. Understand that li-ion batteries fall into sleep mode if they are drained too much. It will not accept any charge then.

Place the two batteries, the live one and the dead one, in parallel formation. Use the clips to connect them, positive to positive and negative to negative.

Leave them for about 15 minutes, closely monitoring the progress. Check the voltage reading. If there is a rise, connect the battery to the charger as you would normally.

How To Tell if a Lithium Battery is Bad?

If your lithium battery has an issue, you will tell from several signs - which can be risky. If the battery is damaged from degradation, it shows:

Low voltage,

Low current and,

Lower capacity in the long run.

The battery is not risky.

High-risk signs include:

Fire or explosion of the battery

Leakage of the electrolyte

Swollen batteries

Lithium is a highly reactive metal when in contact with water. Even the humidity in the air alone is enough to cause a fire.

Also, notice if your battery is overheating, overcharging, and shocks. These actions can promote thermal reactions within the battery, causing major damage.


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