Can I Leave Battery in Drill? – Final Result

Drill batteries are the power source of cordless drills. When we need to store the drill and battery, we have to pay more attention to those. Especially for the drill batteries. Because drill batteries are made with chemical components, if the chemical actions do not occur, a battery can be dead. So when you store, let’s see can you leave the drill battery with the drill.

Generally, you should not leave the drill battery in the drill, if you do not use it for more than 12 hours. Because the drill battery can self-discharge rapidly when it connects to the tool. When this happens continously, the battery can be dead due to fewer charge-discharge cycles.

If you wish to keep the drill battery connecting the drill, you should know its effects. So let’s keep reading on until you find the best solution.

Related Topics

Effect of Drill Battery Power

How does a Li-Ion battery work?

In this topic, we can evaluate the drill battery power generation and what happens when it connects to the tool.

Normally drill batteries are made with Li-Ion or Ni-Cd. Most drill batteries are made with Li-Ion due to the many advantages that it has. So it is better to discuss mostly Li-Ion batteries.

Li-Ion drill batteries are made with small cell batteries that are serial/parallel connected. It can provide 12V, 18V, 20V, etc. These batteries are rechargeable. Especially both Ni-Cd and Li-Ion batteries have self-discharge. When it keeps in the environment, its voltage has reduced due to inner chemical reactions.

When a battery is charged, a bit high voltage is used to store the electrons in the terminals, and when terminals are connected with the conduction wire, it can release the stored electrons. This is called the current of the battery. When a battery is leaving without connecting, its inside has a number of reactions. These affect the self-discharge of the battery.

When a drill battery is connected with the tool, its connection is controlled by the switch. The switch has fewer distance terminals than it is in regular batteries. When the humidity is high, it can affect the drill battery. These all are the factors for the drill battery leaving in the tool. Let’s see all in detail about the drill battery left in the drill.

Effect of Leaving Drill Battery in Drill

If you had to leave the drill battery on the drill, you could see there is a voltage reduction. If you leave it many times, you can see the drill battery has died, or sometimes terminals have rusted due to humidity. So think twice before leaving the drill battery even a night.

I can share my experience with you.

I fully charged my drill battery and mounted it to the drilling machine, and left a night because the next morning, I had to go to work. So the next morning, I checked the tools. What I saw is, Batteries were fully discharged.

This happens due to two things. Later I could identify.

Read More About – Why is My Drill Battery Not Charging? Problems and Solutions

Fully Charge Battery

When the battery is fully charged, its self-discharge rates are high. Due to inner reaction rate is also high. My battery is old, about 3 years. So inside impedance can be reduced due to continuous use. So it can self discharged due to these reasons. And also, fully charging is not recommended for the battery. When it fully charge and discharge, its number of cycles is reduced.

Leave in the Tool

When we leave the battery in the tool, there is a switch to control the power of the motor. The battery is in the conduction medium, and it will increase the rate of self-discharge. Sometimes humidity can increase the self-discharging rate. So it was a bad idea to keep the battery in the tool.

Proper Way of Leaving Battery in Drill

If the battery is not able to leave in the battery, there should be a method to keep the battery. You should keep the battery not connected to the drill machine. It will disconnect any connection between the terminals and terminals that are not connected to any conduction medium.

When you leave the drill battery away from the drill, you should follow short-term methods and long-term methods for the best practice.

Short Term Method

If you need to keep the drill battery for about 1-2 weeks, you should follow the below steps.

  • Remove from the tool
  • Keep it in room temperature.
  • Keep away from conduction medium
  • Humidity 50%
  • Store in dry enviroment
  • Store with low voltage of its maximum voltage
  • Do not store in high temperature area.

But if you use the tool daily, you do not need to store them using the above steps. You can leave the battery and tool without connecting them. You can keep the battery in the charger. It will not overcharge. But it is better if you can charge 90% maximum.

Read More About – How Long Does It Take to Charge a Cordless Drill Battery?

Best Way to Leave Drill Battery for a Long Period

If you are looking to store the drill battery for a long period, you should follow more special steps than a short period. When a battery is stored long period, it can be dead due to self-discharge. So you had better avoid these factors every time. So let’s see what factors are to be followed when you store the drill battery for a long period.

How to store drill batteries for a long period?

  • Remove the battery from the tool
  • Store the voltage 50% of its maximum voltage ( 18V to 9V)
  • Keep the room temperature between 5 °C and 20 °C (41 °F and 68 °F)
  • Keep the humidity 50% (do not put the battery in firdge)
  • Keep away from the pins, clips, paper clips, conduction wires, dust, etc.
  • Insulate the terminals from any insulation
  • Do not store in direct sunlight area
  • Recharge 50% of its maximum voltage after every 6 months
  • Use dry enviroment


  • Self-discharge is the main problem in the leaving drill battery.
  • When the drill battery is connected to the drill, its self-discharge can be increased.
  • When you are not working more than a day. leave the drill battery and drill separately.
  • If you do not use a drill battery for a long time you should follow the above steps.

Tom Mackency

Tom Mackency

Hi, I am Tom Mackency. It has been 10 years that I have been working as a professional woodworker since 2013. I am really enjoying my carrier by creating many kinds of projects in my workshop. But mostly I like for home improvement projects. Home improvement and DIY projects are the most interesting things for me. More than that, the coolest things are power tools. Those are very precious and efficient than a decade ago. So I try to introduce so many things about power tools, woodworking, DIY projects, home improvement and many more interesting topics here.