Dewalt flexvolt battery with question mark

Dewalt Flexvolt Battery (What is it?)

Dewalt is one of the most trusted tool companies out there. They have been around for many years. Contractors and DIYers use there tools all the time because of the quality.

One of the companies biggest goals is to provide high powered equipment run by batteries. They are trying to get rid of tools with cords. That is where the Flexvolt battery comes in. It is one of the most powerful and versatile batteries on the market. Lets take a look just how this battery works and what you can use it with.

Dewalt Flexvolt Battery

The Dewalt flexvolt battery was designed to provide more power. It has 60v of power. You must use the Flexvolt battery on the Flexvolt advantage tools. These are larger tools that require power. You can also use the Flexvolt battery on standard 20v tools and it will provide 4x the runtime.

Volts vs Amp hours (AH)

Voltage in terms of batteries refers to the amount of current being pushed by the battery. The more current pushed, the more power the battery can supply. So a higher voltage means higher power. A higher voltage also translates to less current to do the same amount of work which leads to longer battery life. Dewalt tools use 18v, 20v, and 60v batteries.

Voltage shown on dewalt flexvolt battery

Amp hours refer to how long a battery will last on a single charge. This tells you the amount of energy charge in a battery that allows 1 amp of current to flow for 1 hour. For example a 6Ah battery can give 6 amps of current for 1 hour or 1 amp of current for 6 hours. The Flexvolt battery line comes in 6 ah, 9 ah, 12 ah and 15 ah.

Amp hour (Ah) shown on dewalt flexvolt battery

How the flexvolt system works

The flexvolt system is a unique state of the art battery that provides more power from a single battery. This battery automatically changes voltage when the user changes. tools. It has the ability to provide 20 volts, 40 volts or 60 volts.

The battery contains 15 cells that each have 4 volts of power. This adds up to a max of 60 volts. The beauty of the battery though is that it can sense what type of tool that it is on. It has the ability to switch the series of the cells to provide the appropriate volts needed to run the tool it is connected to.

15 Cells shown in Dewalt flexvolt battery.

So if a flexvolt battery is placed on a 20v tool, the battery will sense this and only provide the 20v that are needed. If the battery is placed on a flex volt advanced tool it will be able to provide the full 60v necessary.

At this time, Dewalt has one 120 volt tool. It is a cordless double bevel compound sliding miter saw. This saw requires 120 volts of power. So by combining two 60 volt batteries you will get the necessary 120 volts of power. THATS A LOT OF POWER!

Two Dewalt flexvolt batteries on miter saw

It is important to note Dewalt batteries are backwards compatible. This means 20v batteries can only be used on 20v tools. While 60v batteries can be used on both 20v and 60v tools.

Flexvolt batteries

Flexvolt batteries are available in 6 AH, 9 AH, 12 AH, and 15 AH. Again the higher the amp hour the longer the run time on a single charge.

All 4 dewalt flexvolt batteries

The 6.0 AH battery – it’s 6.0 AH at 20 volts and is 2.0 AH at 60 volts.

The 9.0 AH battery – it’s 9.0 AH at 20 volts and is 3.0 AH at 60 volts.

The 12.0 AH battery – it’s 12.0 AH at 20 volts and is 4.0 AH at 60 volts.

The 15.0 AH battery – it’s 15.0 AH at 20 volts and is 5.0 AH at 60 volts.

Also as stated above the flexvolt batteries can be used on the flexvolt advantage tools and or the 20v standard tools. They can also be charged on the 20v chargers, they will just take a little longer.

Dewalt flexvolt battery charging on a 20v charger
Dewalt Flexvolt battery on a 20v charger

Flexvolt advantage tools

Along with the Flexvolt batteries Dewalt released its Flexvolt advantage tools. This is a line of tools that when paired with the Flexvolt batteries, will provide maximum power. The line includes (but not limited to): grinders, saws, and drills. The complete guide can be found on the Dewalt website.

Flexvolt advantage reciprocating saw

The tool and battery combo is Dewalts way of increasing a tools power without needing a cord. Prior to flexvolt batteries if you wanted more power in a tool, you likely needed a corded tool. Now with the flexvolt battery and flexvolt advantage tool you you can cut the cord once and for all.

More powerful Dewalt tools
More powerful Dewalt tools

Prior to the flexvolt system when using grinders or larger saws the battery power provided by the 20v battery was not enough. Now with the flexvolt system you can get up to 60v (or 120 with two batteries paired) which is more then enough to run these larger more powerful tools.

One thing to keep in mind though when using the Flexvolt advantage tool line. These tools must be used with the Flexvolt battery. You cannot use 20v batteries with these tools.

Dewalt 20 volt battery
Dewalt 20 volt battery

Flexvolt battery on 20v tools

The beauty of the flexvolt battery is that you can use it on your 20v tools. When used on a 20v tool the battery will sense this and be able to adjust the voltage/power provided. So instead of providing 60 volts of power, it will give the tool the 20 volts it needs.

Since the battery is providing less power to the tool, it will allow for 4x longer battery life. So when using a flexvolt battery on a 20v tool, you will be able to use the tool much longer then if you were using a 20v battery. That is pretty significant.

15 ah flexvolt battery on a 20 volt reciprocating saw
Flexvolt battery on a 20 volt tool

It is also important to note that the Flexvolt batteries will not work with the 18 volt to 20 volt adapters. So if you are still using 18 volt tools with an adapter these batteries are not an option.

Dewalt 18 volt to 20 volt adapter


Dewalt batteries are not cheap. As you can imagine the flexvolt series is the most expensive. The good thing about the batteries though is they tend to last long. If for some reason your battery is not working, there are a number of things you can try to get it going again. Also Dewalt provides a 3-year warranty with there batteries.

The cost for each flexvolt battery is listed below:

Screenshot from amazon showing the price of Dewalt flexvolt battery

As you can see these Flexvolt batteries are very expensive (more expensive then a lot of the 20v tools). Personally I do not have any flexvolt batteries because of the cost. I have found that contractors and carpenters tend to use the Flexvolt system more then DIYers. They use there tools every day and often times need this extra power and or extra run time.


I hope this helped you better understand Dewalt’s Flexvolt battery system. I know all the different batteries can be confusing. If for some reason you are having any issues with your Dewalt battery I recommend reaching out to Dewalt at: 1 (800) 433-9258.

  • Volts vs amp hours
  • How the Flexvolt system works
  • Flexvolt batteries
  • Flexvolt advantage tools
  • Flexvolt battery on 20v tools
  • Cost

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