Method 1: Freeze the Battery

If your computer has a nickel metal hydride (NiMH) or nickel-cadmium (NiCd) battery, you could try freezing it. If you have a lithium battery (which covers all Macs and most new Windows computers), do not try this method.

It might sound fanciful, but this method is scientifically proven to work. By freezing a battery, you’re accomplishing two feats:

1. Gelling the battery’s electrolyte sufficiently so that the charging process can overcome crystallization.
2. Slowing the movement of free electrons so more electrons can join the flow.

Note: If your battery is exceptionally old, all the electrons have probably leaked away, and this method will not work.

Method 2: Over Voltage

This is a method for jump-starting lithium batteries. Remember, lithium batteries will die if left unused for an extended period. You should try to turn any lithium-powered devices on at least once every two days to maintain the battery’s health.

Warning: This method works, but it’s risky. If you overcharge for too long, the battery could explode. Wear eye goggles and perform the process in a large, clutter-free area.

Before you begin, you’ll need three items: a crocodile clip, thin wire, and a laptop charger or power supply unit. The wiring in an Ethernet cable will suffice, if you have an old one lying around that you’re willing to cut up.

Attempting to jump start a laptop battery. Here goes

— Tony Black (@TonyBLK) October 10, 2010

First, you need to locate the positive and negative pinouts on your battery. In theory, these should have clear labels. If they don’t, search Google for your battery model.

Next, cut two pieces of wire. Each of them should measure about 2.75 inches. One of them will play the role of the positive wire; the other is the negative. On the positive wire, remove about 0.4 inches of the protective coating from each end. On the negative wire, remove about 0.4 inches at one end and just under 0.8 inches at the other end.

When you’re ready, insert one end of the positive wire into the battery’s positive pinout, and insert the 0.4-inch end of the negative wire into the negative pinout.

Slot the other end of the positive wire inside the charger’s positive pin. Finally, attach the 0.8 inch end of the negative wire to the negative outer conductor using the crocodile clip.

Now you need to leave your battery for two hours. When disconnecting your setup, exercise extreme caution—this where there is a risk of explosion.

Reinsert the battery into the laptop to test whether the jump start was successful.

Method 3: Replace Battery Cells

This is the most adventurous of the three fixes. You can try to replace some (or all) of the cells in your old battery with functioning cells from a working but unused battery.

Once again, there are a few critical warnings you need to keep in mind:

• The replacement cells must have the same chemistry makeup as the current cells (e.g. lithium-ion).
• Your new cells must have the same rated voltage as the old ones.
• The new cells must have the same or higher capacity as your old cells (measured in mAh).
• The new cells must be the same physical size as the old ones.
• You’ll also need a soldering tool.

To start, remove the battery from your laptop and pry it apart. You will probably need a flat-head screwdriver or putty knife.

Within the battery’s casing, you’ll see a series of individual cells. Typically, they look like regular AA batteries. Each of the cells will be connected to a circuit board with wires. Make sure you make a note of which wires go where. Ideally, you should also use a multimeter to ensure there’s no potentially dangerous residual charge.

Separate the cells from their wires and each other using your soldering tool, then take them out of the case. Next, solder your new cells together and reattach the wires to the correct locations.

Finally, put the battery’s casing back together and let it rest for 48 hours to ensure you soldering work has set.