Battery Guide


Tips & Tricks


Whether you’re a professional contractor or a do-it-yourselfer in your own home, you likely get plenty of use out of your power tools. Thanks to rechargeable batteries, these cordless wonders are incredibly convenient and allow you to complete a wide range of tasks virtually anywhere. But what exactly should you know about batteries to ensure your drills, saws, grinders, impact wrenches, and other power tools are always powered up and ready when you need them?

Cordless tools were once considered somewhat of a liability despite their convenience. Batteries didn’t last very long, which was a major downside if you were planning to use a tool for an extended period of time. Fortunately, battery technology has advanced enough to the point that many cordless power tools can handle the most demanding jobs.

There are several varieties of batteries available for power tools, but the most prominent ones are nickel-cadmium (NiCd), nickel metal hydride (NiMH), and lithium-ion (li-ion) batteries. Each has its respective benefits and drawbacks, making them best-suited to certain tools and situations. We’ve put together a comprehensive guide to help you understand the differences between the main types of batteries and how you should use them.

But first, let’s review some of the key terms every battery user should know.


If you look at the product description of a battery, you’ll likely see many strange terms and abbreviations. To the uninitiated, these may be difficult to decipher. However, it’s essential to know their meanings in order to understand the power, capacity, and other important characteristics of the battery.

Here are several explanations to help you start speaking the language of batteries:

Ampere Hours (Ah)

Commonly abbreviated as “Ah”, an ampere hour is a unit of electric charge. It refers to the total charge a battery can deliver in one hour. To put it simply, the Ah rating lets you know about how long the battery will last per charge. For instance, you may see a battery with a 3.0Ah rating. When used in a tool that continuously draws 1.0 amperes of current, the battery should last around three hours on a full charge. Just divide the Ah rating by the current: 3.0 / 1.0.

Voltage (V)

Voltage is the difference in electric potential between the positive and negative terminals of a battery. It determines the amount of power the battery can provide. The higher the voltage, the more powerful the battery. More powerful tools require batteries with higher voltages. You can find batteries in a range of voltages based on your needs. 4V batteries may be sufficient for light repair work with a small cordless screwdriver, while cutting through thick lumber may require a chainsaw that uses a 60V battery.

Cycle Life

Cycle life refers to the overall life of the battery, or how many times it can completely charge and discharge before losing its capacity. Different battery types have varying cycle life periods. Typically a longer cycle life comes at the expense of overall power and performance. NiCD batteries usually have a cycle life of around 1,000 charge cycles, while lithium-ion batteries have one of approximately 300-500 charge cycles.

Memory Effect

The memory effect occurs when batteries are consistently recharged without being allowed to fully drain. This causes the battery’s charging capacity to diminish over time, as it begins to recognize the shorter charge time as its new charge capacity. The memory effect happens to NiCd and NiMH batteries, but it does not affect lithium-ion batteries.


The main varieties of battery you’ll likely find in power tools include nickel-cadmium (NiCd), nickel metal hydride (NiMH), and lithium-ion (li-ion). Here’s an overview of the traits and features of each battery, along with other info you should know.

Nickel-Cadmium (NiCd)

Nickel-cadmium batteries use nickel oxide hydroxide and metallic cadmium as electrodes. They are the oldest of the three main types of rechargeable battery, first surfacing around the turn of the 20th century. The main advantage of NiCd batteries is that they generally have the longest cycle life at approximately 1,000 charges. But other than the extended lifespan, there are several downsides that make NiCd batteries less appealing than their newer counterparts. They have a comparatively low capacity (usually ranging from 1.2Ah to 2.2Ah) and are prone to the memory effect. As for more practical concerns, NiCd batteries are typically heavier and susceptible to overheating. They’re also harmful to the environment and must be disposed of properly.

Lithium-Ion (Li-ion)

The relatively new standard in the battery world, lithium-ion (often shortened to “li-ion”) batteries hold multiple advantages over NiCd and NiMH. They have the largest capacity of the three main battery types, usually exceeding 3.0Ah. They’re also much smaller and lighter than other batteries, so they won’t weigh down power tools or other devices. Li-ion batteries don’t experience the memory effect, so you can freely recharge them as needed without worrying about eroding the capacity. There are a couple downsides to keep in mind, though. Li-ion batteries have the shortest cycle life at under 500 charges. They’re also the most expensive, so a lithium-ion battery may not be the right choice if you’re on a strict budget.

Lithium-ion battery users have plenty of options to choose from brands like DEWALT, Bosch, Makita, and more. It runs much cooler than other battery packs through demanding applications, so you don’t need to worry about pushing your cordless tools to the limit. Batteries aren't compatible across manufacturers however, so whatever brand of tools you choose to go with, make sure you stay within your same battery platform.


After reading about the pros and cons of each battery, you may already have a sense of which one is appropriate for your power tool needs. While specific requirements may vary among users, we’re confident in saying that lithium-ion batteries are the all-around best choice for powering cordless tools. Their advantages over NiCd and NiMH batteries are simply too significant to ignore, and their drawbacks are usually not especially difficult to overcome for most users.

Yes, lithium-ion batteries have a shorter cycle life than NiCd and NiMH, but they offer more capacity and better performance in each of those charge cycles. They’ll also retain their charge even if you don’t use them for months. Lightweight li-ion batteries are perfect for when you need your tools to provide maximum maneuverability, such as working in tight spaces, overhead, or at odd angles. They’re the most expensive battery type, but a lithium-ion battery should still last about 2-3 years, so it’s a wise investment for the benefits you get.

If you need more proof that lithium-ion is the current standard for power tools, look no further than the fact that li-ion has become the most common battery type for many of the biggest tool manufacturers. You can find a large selection of lithium-ion power tools DEWALT, Makita, Bosch, Craftsman, and other popular brand names.

That’s not to say there aren’t situations where NiCd or NiMH batteries may be a good choice. As the tough, “heavy duty” battery type, NiCd batteries are well-suited to rough job sites and inclement weather. You may want to use them if you frequently use your tools outside or in extreme conditions. And, of course, it doesn’t hurt that they’re the cheapest option.

NiMH batteries are a solid choice if you need more capacity than what NiCd can provide but don’t want to spend as much for lithium-ion. They’re a decent “middle ground” between the three battery types.


If you’ve decided on a lithium-ion battery, what do the biggest tool makers have to offer? Manufacturers like DEWALT offer several battery platforms for their power tools. We’ll touch on a few of the most popular lines below, as well as their key features and benefits.


FLEXVOLT® is the ultimate convenience in DEWALT batteries because it automatically switches voltage when you change tools. For instance, the DEWALT 20V/60V MAX FLEXVOLT Lithium-Ion Battery can range from 20V to 60V depending on the voltage requirement of the tool to which it’s connected. This saves valuable time, as you don’t need to manage multiple batteries for your DEWALT 20V MAX and 60V MAX tools.


DEWALT 20V MAX* tools are engineered to meet the specific needs of the most demanding trades. With 250+ products that keep you productive on the jobsite, 20V MAX* system is perfect for the tradesman or DIYer that's looking to expand their power tool collection from impact drivers and impact wrenches to rotary hammers, grinders, nailers, and more.


The newest addition to the DEWALT battery line-up, DEWALT POWERSTACK™ is the world's first pouch cell battery designed for the construction industry, the DEWALT POWERSTACK™ compact battery delivers award-winning performance utilizing breakthrough technology, offering users a lightweight, more compact battery with 2X the lifetime based on charge cycles vs. DEWALT 2Ah Compact Batteries.


At CPO Outlets, we offer a wide array of batteries and chargers for power tools, many of which we’ve discussed in this guide. If you’d like more guidance in finding the perfect battery, you can always contact us for help from our experts!

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