A Guide to Batteries for Cordless Tools

The battery is what makes it possible for cordless tools to do their job and choosing the correct type of battery technology for that tool is almost as important as the choice of the tool itself! If the battery’s capacity, charge time, or storage characteristics are mismatched to the work or user, the expensive tool it’s attached to might not do the user much good at all.

Fortunately, battery technology has significantly improved in the past decade, and in some cases, the tools that they power can perform just as well as a corded tool.

Features to consider in a power tool battery

If you’re ready to purchase your next power tool, then you need to consider the following battery characteristics before you make your final choice. 

Volts and battery power

This is a vital aspect of any power tool battery. The voltage (V) rating of a battery is a measurement of how much power that battery can provide. Even if you choose a quality manufacturer of power tools, if you pair it with a sub-standard battery, you’re going to be left with a poor final product.

When considering volts, the higher the voltage, the more powerful the battery. Most modern power tools are rated at 18V or 20V. Higher voltage usually means the tool is more powerful – but it also means more weight in the tool and these higher voltage tools also generally cost a lot more. It all comes down to choosing the right tool for the job. 

Amp-hour ratings and battery runtimes

The higher the amp the longer the runtime of the battery. In most cases, this makes buying higher amp batteries the most logical choice. However, higher amp batteries are more expensive, larger, and heavier. You’ll need to consider this when choosing a battery.

What batteries are used in power tools?

Almost all power tools now use lithium-ion batteries, referred to as Li-ion. This is more expensive than the traditional batteries, which were either nickel and cadmium or nickel and a metal hybrid. 

Additionally, Li-ion batteries are more durable and will provide the same level of power until they are empty. Li-ion batteries can be found in a vast array of voltages, from 12-36V and the amps can be as little as 1.2Ah or as high as 9Ah.

Modern-day Li-Ion batteries can provide power for extended periods of time, and recharge fairly quickly – making them a worthwhile investment.

Overview of power tool batteries

As mentioned, there are lots of considerations when choosing the right battery to match your power tool and the job ahead. For example, a Li-Ion battery is smaller and can provide a lesser current for a much longer period than a NiMH battery. But a NiMH battery can deliver high bursts of current when needed.

Let’s take a closer look at each battery type:

Nickel Cadmium (Ni-Cd) batteries

Advantages of this type of battery:

• Very easy to recharge
• Use standard sizes making it easier to swap brands
• Cheap

Disadvantages of Nickel Cadmium batteries:

• Made with toxic metal 
• Must be fully discharged and recharged regularly
• Lower power offering than Li-ion

Nickel Metal Hydride (Nimh) batteries

Advantages of this type of battery:

• Fast recharging
• Standard sizing, so better for compatibility
• Relatively cheap

Disadvantages of Nickel Metal Hydride batteries:

• More powerful than Nicd but still less than Li-ion
• Tendency to discharge by themselves
• Not that durable

Lithium Ion (Li-ion)

Advantages of this type of battery:

• Powerful
• Lightweight
• Doesn’t lose power in use
• No maintenance is required
• Long-lasting
• Environmentally friendly

Disadvantages of Li-Ion batteries:

• Expensive
• Need built-in protection against overcharging and overheating