Dewalt 18v to 20v adapter not working

Dewalt 18v to 20v Adapter Problems (Quick and Easy Fixes!)

If you are having issues with your Dewalt 18v to 20v battery adapter, you are in the right place. I will walk you through some of the most common issues and how you can fix them quickly!

When Dewalt switched from the 18v to 20v battery system they put out an adapter. This allowed people to use there old tools with the newer batteries. Allowing you to save some money.

As with all tools, these adapters come with some issues. Lets take a look at some of the most common complaints and how to SOLVE THEM!

Dewalt 18v to 20v adapter problems

Dewalt 18v to 20v adapter problems are most common with trying to disconnect adapter from the tool. Make sure to disconnect the battery first. Then firmly press the black buttons on the adapter and pull down from tool. If still stuck trying jiggling the adapter as you press buttons and pull.

Dewalt 18v to 20v adapter
Dewalt 18v to 20v adapter

Switch from 18v to 20v battery system

Back in 2011 Dewalt decided to switch from an 18v to a 20v battery system. There are lots of theories out there as to why they did this and I am not going to speculate. If you are curious I recommend doing some research on the topic.

When they did this the entire structure of the battery was changed. They switched from an insert battery pack to a slide on battery pack.

Dewalt old 20v battery vs a new Dewalt 20v battery

As you can imagine at the time this was not a popular decision. They stopped making and supplying the 18v battery packs and chargers. In order to limit push back they came out with an 18v to 20v battery adapter. This would allow people to still use there 18v tools with the new batteries.

Dewalt 18v to 20v adapter with new 20v battery attached

Seems like a fair compromise. Instead of having to buy all new tools, just buy this $30-$40 adapter (price varies depending on where you buy).

So now lets dive into some of the most common issues that people have with this adapter set-up.

Hard to disconnect adapter from tool

This is by far the most common issue that I hear about when dealing with this adapter. It can be very hard to disconnect the adapter from the power tool itself.

There are two black clips on either side of the adapter. You have to press both of these clips relatively hard to trigger the disconnect.

Black clip located on the 18v to 20v dewalt adapter

In my experience I have found that it is easier to disconnect the adapter when the battery is not attached. This means make sure to disconnect the battery before removing the adapter. Sometimes the added weight of the battery just makes it a little more difficult.

Dewalt 18v adapter removed from tool before removing 20v battery
Adapter removed from tool

Another technique that may help is by applying a slight twist/jiggle to the adapter when removing it. Make sure you are holding down the two side clips when you do this. A small twist/jiggle will help jar the connection loose and make it easier to slide off.

If this is truly a major issue for you every time you use your adapter there are a couple options:

  • Leave the adapter on the tool (easy if you only have one older tool you still use)
  • Buy multiple adapters (again they are much cheaper then buying new tools)
  • Use an off brand adapter (these seem to be easier to disconnect then the Dewalt ones)
  • Use a hand clamp to maintain pressure on the release buttons (allows you to apply more power to the pull)
Dewalt hand clamp
Dewalt hand clamp

If the clips themselves are being difficult (hard to press) they may be dirty or jammed. I have found that using some WD-40 and wiping with a rag will sometimes clear the debris. You could also try using an air compressor if you have one. This will help blow any dirt/debris from around the clip.

One thing I strongly recommend is get in the habit of wiping the clips after every use (especially if saw dust is involved). Then try and store it in a place free from dust. I used to store mine in a zip lock bag.

If all this does not work then unfortunately it may be time to bite the bullet and upgrade your tool.

Hard to connect/disconnect battery from adapter

When connecting your 20v battery to the adapter, it is crucial that you press the button on the battery, as it slides down the adapter. This ensures there’s an appropriate connection between the battery and the adapter terminals.

Black and yellow buttons found on Dewalt battery to connect the battery to adapter/tool

As seen in the picture, there is a yellow and black button on the battery (color will vary depending on battery). This is the same button you press to remove the battery from a tool. You MUST press this button when sliding the battery down the adapter. If it is done right, you should hear an audible click, this will indicate that the battery is on the adapter properly. 

If this is not done properly the connection will not be strong enough for the tool to work.

To disconnect the battery from the adapter you must press this same button. As you press the button you should be able to slide the battery right off the adapter.

Battery does not fit

Another fairly common complaint is that the battery does not fit. Unfortunately this adapter does not fit for all of the new batteries that Dewalt has released.

When purchasing this adapter from Dewalt they make it clear that it only works on the 20v max batteries. It will not work on the newer 20v or 60v FLEXVOLT series.

Dewalt also states on there website when purchasing the adapter: “Do not use with Premium Batteries (DCB200, DCB204, DCB204BT, DCB205) in 18V Compact drills DC970, DC759 (use DCB201, DCB203, DCB203BT)”

The premium and FLEXVOLT batteries are higher ah (ampere hour). I have found the adapter only works for 5 ah and below. Anything above 5 ah has an extra seam on the battery. Therefore they will not fit on the adapter.

Adapter will not work on higher ah battery; pictured is a 15 ah battery with X through it

Adapter limits tools use

This adapter makes the tool you are using slightly bulkier and a little heavier.

The dimensions of the adapter are: 7.8 ounces (about a half pound), L = 5.6 inches; W = 3.18 inches; H = 7 inches. The biggest issue I find when using mine is the height. In reality it adds about 3.5-4 inches of height to your tool once inserted. This can limit your ability to use some tools in certain situations.

Height that adapter adds to tool that you are using

An example of this would be if you have to use a circular saw in a tight space. There are many more examples of this as well.

Dewalt 18v to 20v adapter on a circular saw

Unfortunately there is not much you can do about this issue. The height of the adapter cannot be changed. You may be able to adjust the angle of the tool to fit but sometimes this can significantly limit your project.

Other issues

If you are positive you have done everything correct when using the adapter but it still does not work, it is time to look elsewhere. Remember this is a 3 part system: the adapter, the battery and the power tool.

Maybe the battery is the problem. Or is the tool the issue?

Another common complaint that I hear is that you cannot use an 18v charger. That means you have to have a 20v charger.


There are many different reasons why your Dewalt 18 volt to 20 volt adapter may not be working. If that is the case for you, be sure to run through the checklist before reaching out to Dewalt. Sometimes the fix is much easier then you would expect.

  • Dewalt’s switch from 18v to 20v battery system
  • Hard to disconnect adapter from tool
  • Hard to connect/disconnect battery from adapter
  • Battery does not fit
  • Adapter limits tools use
  • Other issues

If you have tried all of these fixes and the adapter system is still not working, you should reach out to Dewalt at: 1-800-433-9258.

One great thing about Dewalt is that most of there products come with a 3 year warranty. Before calling I recommend looking up further information on the warranty policy.

Did this article help you fix your Dewalt adapter? Do you have another issue not talked about here going on with you adapter? If so please let me know in the comments section.

2 comments / Add your comment below

  1. Hi David,
    Thank you for you support to fix the issues on the battery Milwaukee, I did all the steps to trying to fix my battery the last test I did I putting the fuse 15 on the positive side and is burning a soonest I connected the negative cable,
    I noticed have problem in the main board, Do you know which component I have to replaced?
    Thank You very much for your help!

    1. Hi Fernando,

      Thanks for the comment and love. Sounds like with the burning thats a more complex issue then I would be comfortable fixing. Personally I would reach out to Milwaukee (especially if battery is under warranty). If not you could try this video, goes into a little more detail. Hope this helps.

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