Dewalt 18V to 20V Adapter Problems (Comprehensive Guide)

Dewalt 18v to 20v is a popular choice among adapters. Being compatible with most Dewalt 18 V tools, it is known to ensure quality service. However, along with the good service, there are some issues that also might arise when using this adapter. 

Hence, in this extensive guide, I am going to discuss Dewalt 18v to 20v adapter problems

On the adapter, faulty clips or battery not charging with adapter on are the common issues. Cleaning the clogged-up areas of adapter will fix the faulty clips. Remove the battery by gently pushing it while firmly pressing the release button. Charge the battery and the charging problem should be fixed. 

Still not sure? Well, do not fret. Because, in this article, I have talked about it all.

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Dewalt 18V to 20V Adapter Problems: Quick Overview

Here I have provided information on how to deal with all of them.

Problem Reason Solution
Issues with the Clip Clogged up or Dirt on the clip. Clean it properly
Battery won’t fit Using batteries higher than 5Ah Use the right size battery
Battery not charging when the adapter is On Broken holder or damaged ridge Fix all the faulty part
Adapter gets in the way Using the wrong battery Use the default battery
Battery is hard to remove Not using the right size battery Use the suggested battery

Problem 1: Issues with the Clip

When the Dewalt 18v to 20v adapter is placed into an 18v power tool, these clips or chords help keep the adapter in place. The issue is that they occasionally don’t seem to function well.

Especially when it comes to other 18v power tools whose battery placement area can have a different design.

The most delicate parts such as the clips, ridges, and electronic components of the adapter are subject to dirt and debris exposure. This is a major cause of adapter problems and in this case, faulty clips. 


Due to being stuck with dirt and debris, the clips of the adapter might be too clogged up to function. 

Hence, make sure to keep your Dewalt 18v to 20v adapter clean. Wipe it with a light cleaning solution or just with a dry napkin after every use in order to rid it of any clogging which might have taken place due to debris. 

Problem 2: 20V Battery Does Not Fit 

Most often the issue arises when some 20v batteries do not fit. Even though the Dewalt 18v to 20v adapter is a 20v adapter as it states so in the name. And most frequently it starts from 6Ah and higher 20v batteries. 

It happens when you use anything higher than 5Ah batteries. Because there remains an additional ridge on the higher Amp hour batteries in comparison to lower Amp batteries. And it inhibits their insertion inside the adapter and as a result, they halt halfway.


So, you might be pondering on what to do in this situation. Well, the Dewalt 18v to 20v adapter is solely suitable for the 5 Ah 20v batteries. 

Hence, this crucial factor is significant to take note of whenever you are buying a battery or the adapter itself.

Only buy batteries that are within the range of 5Ah. And refrain from using anything in the range of 6Ah, 7Ah, or more. And this issue should not arise. 

Problem 3: Battery Won’t Charge with Adapter On 

And as was already mentioned, sometimes it is most difficult to remove the adapter. The Dewalt 18 v to 20 v adapter’s inability to charge batteries through it is sadly its additional drawback.

The adapter only allows power to flow out, not in, since it is an output device.


This is expected and a given. In case you want to charge that battery, you need to remove that from the adapter first. And then put it on the battery’s charger.

  • And you might be encountering difficulty with extracting that battery from the adapter. In that case, it is vital that you be as gentle as you can while firmly pushing the release button. Eventually, you are gonna be able to get the battery out.
  • A damaged ridge or a broken holder inside the adapter or battery might be inducing it to get stuck. So, always be careful with your battery and adapter usage as these are only made of plastic. 
  • Another thing to keep in mind is cleaning the adapter and battery every time you are done with a project.

This should be enough for you to resolve the issue at hand. 

Problem 4: Adapter Gets in the Way 

Powertools (such as the hand drill) become much bulkier and more obtrusive when using the Dewalt 18v to 20v adapter. 

Although it might be lighter than the 20v battery it connects to, it is actually the same size. In other words, from the viewpoint of a different person, you have two batteries piled on top of one another. 

The Dewalt 18v to 20v adapter also gets in the way while using some power tools, such as the Dewalt 18v tables table saw, which needs a wide workspace. 

An issue arises if you’re cutting a large piece of wood but can only advance past a certain point since the adapter makes the battery larger and causes it to bump into the board, immobilizing the table saw.


In issues like this, utilizing an 18 V battery along with a Dewalt 18 V table saw is going to solve the issue. It will also make your work efficiency much better. 

It is also fairly cheaper to substitute an 18 V battery than it would have been to get a new adapter.

Problem 5: Battery Is Hard to Remove

Once the 20v battery is put into the Dewalt 18v to 20v adapter, that battery becomes difficult to remove from the adapter. This may become an even bigger issue if another 20v power tool urgently needs the 20v battery.


Granted that the Dewalt 18 v to 20 v was designed for 20v batteries. yet the batteries’ positioning may cause them to become stuck. 

  • When attempting to take out the battery from the adapter, it is crucial to hit the release button. It is the big button in front of all 20v batteries.
  • Additionally, it is crucial to keep the Dewalt 18v to 20v converter clean, particularly the sections that slide into the battery or interlock with it. 

These spaces are quickly covered with debris and dirt. This leads to tightening the battery’s grip on the adaptor.


Can I Use a 5-ah Battery Instead of 2-ah Dewalt?

No, the tool was designed to operate at a particular voltage. Employing a battery with an increased voltage might result in overcharging. Using a battery with a lower voltage may require more work and result in overcharging of the tool. In either case, damages won’t occur right away but the tool’s lifetime will be shortened.

What Does Ah Refer to on a DeWalt Battery?

The “Ah” in Dewalt refers to ampere-hour. That basically indicates the charge capacity is what you can see on your battery. This is the quantity of current that the battery is gonna supply to the tool. The supply time period is over the course of an hour. 

Is It Okay to Leave Power Tool Batteries on Charger?

No, it is not recommended to leave the battery charging. Make sure to remove the battery after charging is finished, unless your tool’s instructions state otherwise. A battery’s life can be shortened and damaged by overcharging, and not all chargers turn off automatically.

Wrapping Up 

I hope I have answered all your questions about the Dewalt 18v to 20v adapter problems. Now you know the answer as well as have this extensive guide handy.

Now just pinpoint the issue which fits with yours. Then proceed for the solution. As everything is clarified here in detail, it should not be a hassle. 

This is all as of now. Have a terrific day!

Jim Boslice

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