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

When comparing 2Ah and 4Ah batteries, there are a few differences to consider:

The most important thing is the battery capacity, 4Ah battery will last for twice as long as a 2Ah battery. But then you also need to look at the battery size, or weight. This tells you which one is right for you.

In this blog post, we’ll explain the difference between these two types of batteries and help you choose the right one for your needs.

Keep reading for more information!

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.

2ah vs 4ah batterry

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

Physical Dimensions: The first difference between the 2Ah and 4Ah batteries relates to 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.

Despite the difference in physical size, 2Ah and 4Ah batteries are interchangeable. 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.

Find all you need about the main differences between 2Ah vs 4Ah battery in the one-minute video below:

Find 2Ah/ 4Ah batteries for the most common Cordless Tools below:

Greenworks 40V 2AhGreenworks 40V 2Ah

Weight: 1.84 pounds

Price range: $100-$110

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Greenworks 40V 4AhGreenworks 40V 4Ah

Weight: 2.97 pounds

Price range: $125-$135

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Weight: 1 lb

Price range: $55-$65

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Weight: 1.42 lbs

Price range: $80-$85

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Makita 18V 2AhMakita 18V 2Ah

Weight: 15.2 ounces

Price range: $75-$85

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Makita 18V 4AhMakita 18V 4Ah

Weight: ‎1 pound
Price range: $105-$115

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Ryobi 40V 2AhRyobi 40V 2Ah

Weight: 2.03 lbs

Price range: $70-$80

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Ryobi 40V 4AhRyobi 40V 4Ah

Weight: 3.19 lbs

Price range: $105-$115

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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.

2ah vs 4ah: which is better

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 x 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.

See 4Ah batteries for more power and performance below:

epsoak epsom salt 5 lb

Greenworks 40V 4Ah

SaltWorks Epsom Premium Salt 2 lb


Solimo Epsom Salt Soak 8 lb

Ryobi 40V 4Ah

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.

RELATED: Best Greenworks 2Ah & 4Ah Batteries Review 2022

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.

Benefits of 4Ah Battery

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

Provide more power.

Store more energy.

Benefits 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.

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 20 volts, then the battery must also be 20 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.

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.

Choose the correct battery for your power tools below:

epsoak epsom salt 5 lb

Greenworks 40V 4Ah

SaltWorks Epsom Premium Salt 2 lb


Solimo Epsom Salt Soak 8 lb

Ryobi 40V 4Ah

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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