How to Convert a Cordless Screwdriver to a Lithium Battery

Battery screwdrivers have the same performance as network models. The advantage of cordless types of screwdrivers in their mobility. However, for a power tool to serve more than one year, you need to figure out how to properly store its battery. In particular, know how to store nickel-cadmium batteries for screwdrivers.

How is the screwdriver battery

A rechargeable battery is a chemical current source used to operate wireless types of power tools. The accumulation of electricity occurs due to what is happening in the battery electrolysis. This process creates a constant voltage of the required level.

The voltage in the battery occurs due to the potential difference between the cathode and the anode. The unit of capacity is ampere hour. This value shows the amount of current that is issued by the battery for an hour.

How to Convert a Cordless Screwdriver to a Lithium Battery

The battery pack (battery) does not depend on the type of screwdriver model.

The following structural elements are included in it:

  • The housing on which the contacts are located;
  • Series-connected power elements (batteries);
  • A thermistor that protects the battery pack from overheating.

Thermistors are not available on all models. The tool body, consisting of two parts, is plastic. It houses a dozen energy storage devices (in some cases there are more). The batteries are interconnected in a single serial circuit.

The extreme terminals are connected to the contacts located outside the housing. Using these contacts, the tool connects to the charger. The output voltage of the battery pack is the sum of the voltages of the connected batteries.

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Outside the battery housing there are four contacts:

  • Two power contacts (positive and negative), the purpose of which is to charge and discharge the battery;
  • Contact located at the top for controlling the thermistor;
  • A contact capable of using a special station to charge and equalize the sizes of the charges of each drive unit included in the composition.

The following types of batteries are available:

  1. Nickel metal hydride (or Ni-MN). They have an output voltage of 1.2 V. The manufacturers of such batteries position them as environmentally friendly. This also applies to production and further disposal. Despite the small dimensions compared to other types of batteries, they have more capacity. Another plus of drives of this type. Performance at low temperatures. The disadvantages of Ni-MH batteries include high cost, limited life and increased self-discharge. When working, it is not recommended to discharge them completely.
  2. Lithium (or Li-ion). The voltage of this type of battery is directly proportional to the number of drives included in the battery. The range is from 1.2 to 3.6 V. Li-ion batteries have a control board and a special controller that monitors all power links entering the unit. The advantage of lithium batteries is the lack of a “memory effect”, high capacity, low weight. The absence of a “memory effect” allows you to charge the battery as needed. It is advisable to charge it well before long work. The charge can be stored for a long time if the battery is at least half charged. The disadvantages of this type of battery include their high price, short life, inability to work at low temperatures. Batteries of this type are the most common. They are equipped with most construction tools.
  3. Nickel-cadmium (or Ni-Cd). They are the standard battery for all power tools with batteries. The advantages of Ni-Cd-type batteries are their: low price, quick charge function, maximum load current transfer function, the ability to maintain high capacity at temperatures below twenty degrees, the ability to perform a charge-discharge cycle up to a thousand times.
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How to Convert a Cordless Screwdriver to a Lithium Battery

How to charge batteries to increase battery life

To properly charge the battery, remember the following:

  1. During the first use of the tool, it is better to charge the battery. It happens that during storage they are discharged.
  2. In nickel-cadmium batteries, the maximum capacity appears after the third charge-discharge cycle. Next, the drive is charged when the minimum power occurs.
  3. Lithium batteries are charged as needed, regardless of charge level, since they lack a “memory effect.”

Features of charging nickel-cadmium batteries

Immediately before using any power tool, you need to study the instructions with the recommendations of the manufacturer. All tool brands have them, for example, such as Makita, Metabo or Interskol.

In these instructions for charging nickel-cadmium batteries, you can find a number of identical points:

  • It is necessary to charge the battery taking into account the temperature regime (air temperature not lower than 5 degrees);
  • It is advisable to store the charged battery separately from the screwdriver so that contact oxidation does not occur;
  • Control the charge level using the indicator built into the charger;
  • Nickel-cadmium batteries are always charged to maximum and discharged to minimum values.

How to store the battery

Any craftsman who is careful about power tools cares how to properly store the battery from a screwdriver. Compliance with the rules of maintenance applies to all types of batteries.

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What you need to remember:

  1. If it is decided to send the screwdriver for storage, then before that it is worth discharging and recharging the tool several times.
  2. For storage of the battery, the optimum positive temperature is 10 degrees. Avoid freezing the appliance.
  3. It is recommended to charge every six months. This procedure increases battery life.
  4. It is desirable to disconnect the current source from the screwdriver, while removing all contaminants from its surface. Remove oxide from the contacts with a special cleaning agent or alcohol-based liquid.
  5. Nickel-cadmium batteries should be slightly discharged. This is done because of their fast self-discharge.
  6. Avoid direct sunlight and moisture on the chassis. High temperatures can melt the plastic case, damage it, and cause loss of efficiency. Ingress of water will also ruin the state of the internal elements of the battery.

Specialists in such cases recommend doing “overclocking” to such batteries. To find out what is the reason for the decrease in operating efficiency, the battery is sorted out, problem areas are calculated. Then the elements are charged again. For charging, a large current is first selected, then, after another discharge, a small current is selected.

If the battery retains electrolyte (it may evaporate), this procedure will help reanimate the battery.


If you do not neglect the information on how to store Ni-Cd batteries for screwdrivers, you can significantly increase the tool life.