Different Battery Packs For Cordless Drills: Does Lithium Ion And Nickel Cadmium Just Confuse You?

When you shop for any electronic product that is battery powered you’ll see a lot of confusing terms. Battery operated drills are no different and understanding the different types of batteries is very important. Especially if you rely on them all day for your job.

In this article, we try to bring you some easy to understand information to help you tell the difference between 3 of the most common types. We also look at how to figure out what type of battery best suits you.

And more important, to help you figure out the detailed technical specifications. You know the ones that look like you need to be a physics major to really understand?

All those specifications will ultimately tell you how well a product is suited to your needs. It will tell you how many charges you can expect to go through. What the voltage is and what the capacity is.

If you don’t want to constantly be switching batteries and investing in many backups, then you can make a big difference by buying something better suited. It might cost more, but in the long run it could save you money and downtime.

Quick Overview

When it comes to batteries it’s all about the types of metals used inside. One of the most common types you see advertised would be a lithium ion battery pack. In many ways, these serve the best purpose. They are reliable. They last a long time and they don’t have a memory effect (more on that shortly).

But there are two other quite suitable technologies and they are Nickel Cadmium and Nickel Hydroxide. These are generally cheaper and can be used for more powerful voltages and Watts. They do have some drawbacks though.

First of all, you will always want to fully discharge them before they are placed in the charger. This is because of a memory effect that results in part of it not being fully charged. Once this effect kicks in it can be difficult to get rid of. And the result is a battery that doesn’t last as long anymore.

The second problem is that when they are not in use they tend to discharge a lot quicker. All batteries do this over time. But Lithium Ion ones hold their charge far better. So, if you tend to go several days or weeks between using a battery then the Nickel based ones are not the best idea.

The 3 Main Types

As already mentioned there are 3 most common types of rechargeable batteries. In this section, we’ll take a closer look at them. But don’t worry, this is not going to be a boring physics lesson. A lot of the technical detail is only useful if you’re an electrical or electronic engineer.

We’ll basically highlight some of the issues that you can have with the different types. That way you can either make sure you avoid those problems. Or else you might just avoid that type of battery.

Nickel Cadmium Batteries (NiCd)

These types of batteries were first introduced over 100 years ago. The main benefit of these is that they provide quite a high amp output. So, if you have tools that require a lot of power then these do work very well.

On weight to amp ratio they are still among the best options available. One thing to be careful of though is that you have to watch out to be using the right nickel cadmium battery charger. Dependent on the output, the charge rate has to be different. Using the wrong one can quickly result in overcharging which greatly reduces the life cycle.

Nickel Metal Hydroxide Batteries (NiMH)

One of the main downsides with a nickel metal hydride battery pack is that the self-discharge rate can be quite high. If you tend to leave your batteries unused for several days or weeks at t time, then be prepared to charge them again before use.

They are nowhere near as good an option as the Lithium ones up next. But they are an awful lot cheaper. One great advantage of them is that they provide a high current right through each charge. You essentially don’t get a constant gradual reduction in output.

Lithium Ion Batteries (Li-Ion)

The Lithium Ion battery is by far the best option, but it comes at a price. The majority of power tools these days will come with one. And if you ever have a choice, then try and stretch your budget.

The first advantage is that the self-discharge rate is less than 2% per month. So, even if you only occasionally use the device, it’s unlikely to have a completely drained battery each time you pick it up.

The life cycle is reasonably good mainly because it’s easier to partially charge without the memory effect. This really justifies the cost, as you will save money over the long term by not having to replace them as regular.

You will also find that these types are a lot lighter than the others above. That means that if you have an already heavy tool, it becomes a bit less tiring to work with. Alternatively, it allows you to have a battery of the same size that lasts a huge amount longer.

What Are Manufacturers Doing?

The vast majority of mid to high-end products on the market come with Lithium Ion batteries. They last the longest on each charge and have a good overall life cycle. There might be some specialized tools out there that have very high amp requirements. These would often still use Nickel based types. That should not really be seen as a negative. The extra amps might be a lot more important for the usage.

Where companies are making some innovative improvements is in the general design of the batteries. On the inside, they’re all pretty much the same. The problem is, that you could have a drill and an impact wrench from the same company with different battery connectors.

That means you won’t be able to just interchange them. Some companies like DeWalt are now introducing bare tool products. These can use the same battery for many different devices.

Over time you could start buying all your power tools from the same company, and you’ll only need to have one set of batteries and chargers. This can save a lot of money on equipment. And you don’t have to go looking for specific batteries every time you need to change one.

What Specifications Are Important?

No matter what type of battery you buy, there are certain specifications that you need to focus on. When you understand these, you’ll be in a much better place to really understand if you’re choosing the right one.

Obviously, the type of battery has impacts on the below specs. But it’s more important to be able to compare even batteries of the same type. You could have two Lithium batteries that look almost the same. But the devil is in the detail and just looking for the right connector could leave you short on power.

Discharge

When it comes to discharge what you need to be aware of is that all batteries will self-discharge over time. With rechargeable batteries, this can vary a lot between the three most common ones.

Nickel based technology will discharge without use at a rate of 5% to 20% per month. That is quite a lot and means that if you don’t use your power tool for a couple of months, you could end up having to charge it first.

With Lithium based devices this is hugely reduced. At most you’ll get a rate of 2% and some high-end products can give you even less than 1%. If you want to make sure you don’t lose large amounts of each charge, then the best option is always Lithium.

Voltage

Makita XDT042 18V LXTThis is what is often referred to as the size or power of your battery. You might think that size would mean physical, but not in the world of physics.

Historically, one of the most popular rechargeable options was the 18v NiCd battery. It provides plenty of power for most tools and was cheap to produce. But as with everything in life, power tools have become more powerful. And that means that you might have old batteries that fit new tools, but don’t provide enough power.

Here is a rough guide to show you the different levels of power requirements for different uses.

  • Light: 7-15v
  • Medium: 12-18v
  • Heavy: 18-36v

The most standard voltage you will find these days is the 20 V option. The good thing is that it will work perfectly well with tools that require a lower voltage.

Capacity

If you’re a hobby DIYer then this is probably not that important. Capacity is essentially how you can tell how long the battery will last. And larger capacity always means larger size.

Over the years, the size to capacity ratio has come down a lot. And companies like Tesla have made a huge contribution towards improving that ratio. And it continues to improve.

As a professional contractor in any field, you will want to reduce the amount of times you have to switch batteries during a working day. This always ends with downtime and it requires you to have more devices charging at any given time.

Memory Effect

This sounds like a strange thing to attribute to such a simple electronic device. But if you remember back to the early cell phones of the 90s, then this was actually a significant problem. What this refers to is that if you didn’t discharge a battery fully before charging it again, the part of the battery that is not charged is remembered over time. And as a result, it stops getting charged.

That reduces the overall capacity and can be difficult to get rid of. With rechargeable lithium batteries that is not the case. The memory effect simply doesn’t exist and that means you can just charge the batteries whenever you want. You don’t have to wait until it’s completely discharged.

Maximum Charges

This essentially will refer to the maximum number of times you can expect to charge a battery. You will see this referenced as the life cycle. For lithium based batteries this is one of the main downfalls. Even the best products will support a maximum number of charges of about 500-600.

Nickel hydride battery types on the other hand will give you substantially more. It would not be uncommon to get more than 1000 charges out of each one. That assumes they are charged, used and stored correctly and always fully drained.

When it comes to choosing, you really have to weigh up the different costs and options. For very high intensity use where you need to charge a battery multiple times a day, this can be a deciding factor.

Conclusion

Battery technology is constantly changing. But the uses for the different types have largely stayed the same. Capacity to size is improving for all of them, and even Nickel based ones are discharging at a slower rate.

For the majority of people the Lithium Ion based ones will work best as they hold their charge longer and have a larger capacity. But, there are very good reasons to go for Nickel. If you need to charge them a lot due to constant use, then you could end up saving money because you get a longer life cycle.

It’s a careful balance that shouldn’t be too difficult to get right.

About the Author Randy Thompson

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