2Ah vs. 4Ah Battery For Cordless Power Tools: Do More Amps Mean More Power?

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Sales of cordless power tools have been on the rise in recent years. These days it isn’t only professionals but homeowners who are using such equipment. Not only are they much lighter, but also much easier to handle and use. Plus, they don’t stress the user as they don’t vibrate as much.

But to keep these tools running, they need the right kinds of batteries to provide power to them. There is a wide selection of different types of rechargeable batteries available for use in such tools. But in this article, we are taking a closer look at the 2Ah vs. 4Ah battery for cordless power tools.

What Are the Differences Between 2Ah and 4Ah Batteries?

There are a couple of differences between 2Ah and 4Ah batteries that you need to know about.

Physical Dimensions: The other difference is concerning the dimensions of these batteries. Generally, 2Ah batteries measure between 4.8 x 3.2 x 2.2 inches and 7 x 7 x 3 inches. As for 4Ah batteries, these measure between 6.5 x 4 x 3 inches and 8.25 x 4.63 x 3.38 inches.

Some battery brands tend to provide 4Ah batteries with the same physical size as 2Ah. This allows users to exchange a 4Ah battery and have more working time with their cordless power tool.

Weight: The difference in size also leads to the weight difference, which is important if you use your cordless tool every day on workpieces. In these cases, choosing a lighter battery can help you carry out the work efficiently without becoming tiring to hold.

Battery Capacity: The first difference between the 2Ah and 4Ah batteries relates to energy capacity. The 4Ah has more space available to store more energy. In turn, it means that it will provide power to cordless tools for longer; it will provide power for twice as long as a 2Ah battery.

How Long Does a 2Ah/4Ah Battery Last per Charge?

How long a battery lasts is defined by the term Ampere Hour. This shows you the number of hours a battery will last for when it uses one ampere of current.

So, for example, batteries with a 4-Ampere hour rating will last for 4 hours when it uses 1 Ampere of current. But it would then only last for 2 hours if it were to take 2 Amperes of current.

To work out how long the battery you are using will last when fully charged, you should use the following formula.

how long does a 2ah battery last?

So for battery running time, multiply the capacity in ampere-hours by voltage, dividing this by the appliance load in watts.

Battery Run Time = (Battery Capacity . Voltage) / Power

Battery run-time (hour); Battery capacity (Ah); Voltage (V); Power (Watt)

For example, using a 2Ah battery in an 18V cordless drill that’s load in watts is 150 will provide power to that tool for up to 0.8 hours, as shown in the formula below.

(2Ah x 18V): 150W= 0.48 hours

Is Higher Ah Battery Better?

A higher Ah rating battery is a good idea as it will provide power for a device for much longer before recharging it. Also, they can deliver more power and performance compared to ones with a lower Ah rating.

As a result, you will be able to get more work done before the battery with the higher Ah rating needs to be recharged.

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Greenworks 40V 4Ah

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Is a 4Ah and a 2Ah Battery Interchangeable?

The answer to this question is yes. But before you do decide to use a 4Ah in place of a 2Ah, you need to consider certain things first, which we discuss below.

As already stated above, yes you can use a 4Ah battery instead of a 2Ah one. But you must make sure the replacement battery is of the same voltage if you intend to do this. So if the 2Ah battery you currently use is a 40 volt one, then the 4Ah battery needs to be 40 volts. 

The other thing you need to look at is the dimensions of the battery. In most cases, batteries with a higher Ah rating are going to be bigger. So it would help if you made sure that the battery you’ve chosen has the same dimensions as the battery being replaced. This will help to ensure that it fits easily into the designated space on the cordless power tool.

Does Higher Ah Mean More Power?

As you’ll soon discover, the Ah rating affects not only its run time but also its performance.

For example, think about how water flows through a garden hose compared to a fire truck. Both are connected to a mains water supply and use the same amount of water pressure. But the hose on a fire truck can deliver more water when fully open.

Electrical systems behave in the same way. You may have cordless power tools that use more current, so batteries with a smaller capacity will run out of power quicker. Also, prevent the tools from working at their optimum levels.

Pros of 4Ah Battery

Run longer for projects that need to be powered for a period of time.

Provide more power.

Store more energy.

Pros of 2Ah Battery

Weigh less, better for working in remote locations like climbing ladders.

Much cheaper to buy.

Perfect for small projects.

As you will see above, using a battery with a higher Ah rating is a good idea. Just make sure that the one you are using to replace the original is of the same voltage.

Find purchasing options for your Cordless tool replacement batteries below:

GreenworksCapacityVoltageSize (in)Price Range 
Greenworks 294622Ah40V6.2×3.2×3.4$100-$110See more
Greenworks 294724Ah40V6.2×3.2×3.4$125-$135See more
DEWALTCapacityVoltageSize (in)Price Range 
DEWALT DCB2042Ah20V‎7x7x3$55-$65See more
DEWALT DCB2034Ah20V7x7x3$80-$85See more
MakitaCapacityVoltageSize (in)Price Range 
Makita BL1820B2Ah18V‎3×6.75×6.5$75-$85See more
Makita BL1840B4Ah18V3×6.75×6.5$105-$115See more
RyobiCapacity VoltageSize (in)Price Range 
Ryobi OP402012Ah40V6.5x4x2.87$70-$80See more
Ryobi OP40404Ah40V6.5x4x3.25$105-$115See more
2Ah & 4Ah Battery Recommendations for Common Brand Cordless Tools

2 Things to Consider before Buying a Higher Ah Battery

When it comes to looking at buying a higher-rated Ah battery, consider the following.

Battery Voltage

This is important as you need to make sure the battery you select comes with a voltage compatible with your power tool. Importantly, you choose the same one to ensure that your cordless drill or saw operates correctly. So if your tool requires 24 volts, then the battery must also be 24 volts.

Make and Model of Your Cordless Power Tool

Look closely at the brand and model of the power tool you are using. Make sure that the battery you are thinking of buying is suitable for using in your tools. Most third-party batteries will list the make and the model they are compatible for use with.

Just as choosing the right cordless power tools for the job, you must select the correct battery. If you don’t select the right one, your power tools will not work as well as they should.

Not only are you likely to notice that they do not perform as well, but also you may find that they don’t last as long. What could be worse than drilling a hole and suddenly your drill stops working.

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Greenworks 40V 4Ah

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But hopefully, the information provided above will help ensure that you select the right battery for your power tool and the job.

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