Understanding Cordless Drill Battery Types

cordless drill battery

If you plan on buying a cordless drill, then the most important element will be the battery type that you decide to go for. If you use cordless drills then essentially they will either use;

  • Nickel Cadmium batteries (Referred to as NiCd)
  • Nickel Metal Hydroxide batteries (referred to as NiMH)
  • Lithium Ion batteries (Referred to as Li-Ion)

cordless drill batteryAll of the top brands like Dewalt and Craftsman will use these types of batteries. We shall look at the differences below, but it is worth mentioning at this stage, that these also come in different sizes. These sizes will have properties such as:

  • Voltage
  • Amperes
  • Watts

It is the combination of the above three properties that determines the actual power and torque of your drill. It is also the type of battery that will determine how long the battery will last without needing to be re-charged. the best way to think of the properties of a battery is:

  • Its capacity
  • Its storage properties
  • Its charge time

Although there are many features to consider when buying a cordless drill, the battery should be your number one priority. It is the same is you plan to remove a battery and replace it with a new one. In my humble opinion the battery type you choose is as important as buying the actual drill itself.

Manufacturers Bare Tools and Batteries

cordless batteries and bare toolsMost of the bigger brands are now adopting what is called the “bare tool” product. There are many types of cordless tools such as drills, drivers, impacts etc.

Manufacturers realized that a cordless battery could be used to work on any of their tools if they made the battery and the connector as standard.

The basis of this buying style means that once you buy a battery and a charger, then you could buy the tools at a much cheaper price as each one could be sold as the bare tool only.

It does make sense of course, however the down side is that the batteries are seldom interchangeable between the brands. That is of course good news for the brand as you are stuck with their tools, but bad news for the consumer if you prefer different tools offered by different brands.

If you have read any of my articles you know that I am a big Dewalt user and for me it works really well. I own a couple of batteries and chargers made by Dewalt and these can be used for all of my cordless Dewalt products.

Understanding The Properties of Cordless Batteries

If you are going to purchase a cordless drill then it is useful to know what properties to look for in a cordless battery. They are important to understand as it will help you make a better buying decision. The main characteristics are:

  • The cycle life
  • Discharge rate
  • Voltage Sizes
  • Capacity and Run Time
  • Memory Effect

I am always reluctant to write long and boring technical descriptions so I will try to summarize the most important points below.

The cycle life is simply how long the battery is expected to last and to work efficiently. All rechargeable batteries will eventually come to a state where they are useless. At that stage they will need to be replaced.

Clearly this will depend on how much use your drill is going to get. the average life cycle is around 800-1,000 charges and after that, the battery is not worth charging. For some people this lifetime could be a year, and for others it could be much longer. It all comes down to the amount of use and how often the battery has to be charged.

The Importance of Self-Discharge

Every rechargeable battery when not in use starts to lose its charge. The important point to understand about this is how fast this happens. Say for example you used your drill for a few minutes one day, and then didn’t want to use it again for another week. With some batteries this would mean having to charge it first as it would have self-discharged completeley. The Lithium-Ion style of battery is the best type as they hold their charge really well.

Understanding Voltage Sizes

Batteries come in different sizes based on the volt’s measurement. The higher this voltage is then the more power you will get. This is an important consideration and your decision will come down to the type of work that you will expect your drill to do.

  • 7-12 volts will handle light work
  • 12-18 volts will handle medium types of work
  • 18-36 volts will be required for the heavy duty types of work

For many years the 18V led the way as the most popular choice but recently that trend has changed and is now the 20V battery, simply because it offers additional power.

Capacity & Run Time

For professionals and contractors, this is probably the most important of all the characteristics. Serious drill users will always need to have a battery that can give them the most use. They are willing to pay additional money to get this extra battery life.

Memory Effect

This does not happen with Lithium-Ion batteries but it does with the other two types. The simple explanation for this is that batteries do remember at what point they are discharged and charged to. Over time the remembered part of the battery stops charging that part and the overall charging capacity of the battery reduces until it becomes redundant.

How To Test and Rebuild a Cordless Battery

So What Makes The Best Batteries for Your Cordless Drill?

As you know at Tool and Go, we do like to keep things pretty simple. These days, the price differential just means that there is very little difference in buying a small voltage battery as compared to buying a higher one.

20 volts is by far the standard these days. So if you have decided on a cordless drill, and you have decided on a brand, then always go for the 20 Volt Lithium-Ion option or bigger if they have it available. That way you will get more power and have a battery that holds its charge so as it it will be ready as and when you need to use your drill.

Enda McLarnon
 

Enda McLarnon is now retired and is now enjoying writing about his love of power tools. All types of these tools are now available and they make working on projects and DIY jobs around the home a great deal of fun