dewalt 20v hedge trimmer problems

Dewalt 20V Hedge Trimmer Problems: 9 Fixes!

The trimmer not starting is one of the major problems of the Dewalt 20V Hedge Trimmer. Also, to me happened many times to stop during use. Another issue with the trimmer that I encountered is the battery not charging. Besides these, often the trimmer underperforms. Overheating & excess vibrations are also some issues seen in the Dewalt 20V.

The Dewalt 20v Trimmer helps to trim hedges very conveniently. But sometimes this Dewalt 20v suffers from various problems.
As an expert with years of experience in this field, I prepared a guide about the Dewalt 20V Hedge Trimmer Problems. Here I tell you about the main problems of Dewalt 20v and how to solve them.

Key Takeaways

  • The Dewalt 20V Hedge Trimmer might suffer from several problems.
  • Some of the problems are easily fixable and can be solved at home.
  • Taking professional advice is a must for solving some severe issues of the Dewalt 20V Hedge Trimmer.
  • If you are uncomfortable working with electrical parts, take your Dewalt 20V Hedge Trimmer to a mechanic.

Dewalt 20V Hedge Trimmer Problems: Solutions at A Glance

Dewalt 20V Hedge Trimmer
Source: DeWalt

In the table below I depict all the common problems and solutions of the Dewalt 20V Hedge Trimmer at a glance. 

Trimmer Not StartingLoose/Damaged or Uncharged BatteryConnect the Battery Properly
Trimmer Stopped During UseLow BatteryCharge The Battery
Battery Not ChargingDamaged BatteryReset the Battery
Trimmer Under-PerformingBlocked Spool/Faulty TriggerProper Maintenance & Cleaning
Excess VibrationBroken or Jammed-Up SpoolCleaning The Trimmer
OverheatingDirt AccumulationRegular Cleaning
Jam in LineIncorrect Winding of Cutting LineFixing The Winding
Uneven CuttingHolding The Trimmer UnstablyHolding The Trimmer with Proper Grip
Loose StringsStrings Got TwistedReplace the String

You might be confused even after going through the table. Keep reading for details on the solution methods (for avoiding buying a new one). 

Dewalt 20V Trimmer Problems: Detailed Solutions

dewalt hedge trimmer stopped working
Source: OPE Reviews

Detailed solutions will help you to solve the problem more precisely and accurately. So make sure to be attentive while you go through this section

Trimmer Not Starting:

This is a very common issue found in the Dewalt 20V Hedge Trimmer. This causes a very frustrating situation for the user. 

This issue happens because of several causes. An uncharged battery, a loose battery connection, or a damaged battery can cause the problem.

Besides the battery issues, the damaged motor of the trimmer can prevent it from starting. Also, the trimmer will not start if the lock-off lever is dirty and doesn’t go all the way.


The solution is simple if the starting problem happens due to battery issues. Let’s check the solutions.

  • Make sure that the battery is properly charged. The Dewalt charger can be used to check the battery charge.

The charger has a red LED light to serve this purpose. The light flashes when the battery is being charged. The light glows constantly when the battery is fully charged. The light will not turn on if the battery or the charger is damaged.

  • Connect the battery to the Dewalt 20v Trimmer properly. Make sure the connector pins are clean. The battery should sit comfortably in the chamber. However, restrain from applying access pressure while connecting the battery. 
  • The lock-off lever is to be pushed to start the motor. Make sure that you have moved the lever to the On position. Dirt accumulated in the lever can prevent its movement. Use a contact spray to clean the lever easily.
  • Repair the cracked area or replace the battery with a new one if irreparable.

Trimmer Stopped During Use:

  • The Dewalt 20v Hedge Trimmer mainly stops suddenly due to a low-charged battery. 
  • Using the trimmer for an extended period can cause the issue too.
  • The trimmer can also stop if any debris gets stuck in its spool. Debris prevents the spool from rotating.
  • Over-extended swath length can also be the reason behind sudden stops. 


  • Charge the battery completely before using it with the trimmer. The LED light on the Dewalt 20v charger will keep glowing constantly if the battery is charged completely.
  • Don’t expect that the trimmer will go on for eternity even if the battery is full. Usually, the trimmer runs for 30 to 35 minutes at a low speed. And at a high speed, the battery can support the trimmer for 20 to 25 minutes. 
  • Clean the spool if any debris gets caught in it. Turn off the battery first. Then remove the spool from the trimmer. Reach inside the housing and gently pull the disk. Now check if there is any dirt in it.
  • The swath length should be set according to the suggestion of Dewalt. Dewalt recommends a swath length of 13 inches. So make sure to ensure this length.

Battery Not Charging:

The Dewalt 20v Trimmer battery must be charged before use. However, problems arise if the battery does not get charged. Sometimes the fully charged battery does not work and causes issues. This issue arises because of the following factors.

  • The power outlet is out of order.
  • The Dewalt 20V Hedge Trimmer battery is damaged.
  • The battery charger does not work.

It’s important to find out the source of the problem before jumping to the solutions. Here is a step-by-step guideline for finding the issue.

  • Test the power outlet with another working electrical device. 
  • If the power outlet is right, insert the Dewalt charger in it. Connect another piece of functional battery inside the charger. The LED light on the charger light should turn on if the set is working. If the light turns on, the charger is right. Or else, the charger is damaged.
  • If the power outlet and the charger are functional, the problem is with the trimmer battery.


  • The charger will not work at a high-temperature place. Use an outlet where the temperature is between 40 Fahrenheit to 105 Fahrenheit. This should solve the issue.
  • Sometimes the charger still might not work even after following all the steps. In that case, you have to hire a professional. You might need a new charger. 

You have to reset the battery to fix it. You will need another working Dewalt trimmer battery for this purpose. Once you have the battery, fix the battery by following the guidelines given below.

  • Keep both of the batteries on a flat surface. They must be kept side by side. 
  • There are two terminals in each battery. They are marked as B+ and B-. Take a piece of wire and join the B+ terminal of the batteries together.
  • Take another piece of cable and join the (B-) terminals of the batteries. Connect for a few seconds and remove it.
  • Now your dead battery should be working.

Trimmer Under-Performing:

The Dewalt 20v Hedge Trimmer can run at a speed of 5800 RPM at a 0.095-inch line. This speed is enough to cut all the edges without any effort. But sometimes the user might face weak trimmer performance.

The causes behind the below-average performance of the Dewalt 20v trimmer are given below.

  • Dirt is accumulated in the Dewalt trimmer spool. 
  • Use of improper line in the trimmer. 
  • The gears of the motor are sticky.
  • The speed trigger is malfunctioning. 


Fixing the performance issue in the Dewalt 20v Hedge Trimmer is not very hard. Here are the required steps.

  • You have to clean the spool. Dismantle the batteries first. Now reach inside the housing and gently pull the disk to remove the spool. Make sure there is no dirt in it.
  • If the speed trigger is dirty or greasy, take it to a professional. It is not wise to open the Dewalt trimmer to clean the trigger all by yourself. 
  • The trimmer line must be 0.095 inches. If the line is too thick or too thin, the trimmer’s performance will be reduced. 
  • If the problem is not fixed, take the Dewalt 20v trimmer to a mechanic. He will open the trimmer to clean the gears and other parts.

Excess Vibration:

The cutting operation can be pretty troublesome if the Dewalt 20v trimmer vibrates excessively. The trimming can go completely wrong because of the vibration. However, solving this issue is not as complex as solving Dewalt circular saw electric brake issues.

A broken or jammed-up spool causes excess vibrations in the Dewalt 20v Hedge Trimmer. Also, uneven cutting lines can be the reason behind this issue. 


  • Open the spool and clean it.
  • The line might have a broken side or a bad spot. Extend the shortened line and make it of even length. This will stop the vibration. 

You can remove the vibrations by ensuring an even line and clean spool.


The Dewalt 20V Hedge Trimmer runs at a very high speed. So it can get quite hot during its operation. Anyway, the temperature must be within limits. The Dewalt trimmer overheats due to clogs in the inlet and exhaust ports.


Only regular maintenance can fix the issue of overheating. Clean the Dewalt trimmer after every operation. You can use clothes to keep the exhaust and inlet ports clean. This will ensure optimum air movement and the trimmer will not overheat.

Jam in Line:

This situation arises due to the dirt inside the spool. It can also happen if the winding is too tight. 


  • Gather the necessary tools and materials first. You’ll need a replacement trimmer line (0.095 inches in diameter), scissors, and safety gloves.
  • Remove the battery from your Dewalt trimmer for safety reasons.
  • Take a look at your trimmer’s spool. If there’s any old line remaining, remove it.
  • You’ll find arrows indicating the winding direction on the spool. This is crucial for proper feeding.
  • Cut the length of the trimmer line, to approximately 10 feet. This will be enough for most jobs.
  • Now insert one end of the line into one of the eyelets on the spool. Pull it through until both ends are even, leaving about 5 feet on each side.
  • Hold the spool firmly and wind the line evenly around the spool, following the direction indicated by the arrows. 
  • Once you’ve wound the line to your desired length (usually about 13 inches), secure the ends in the notches provided on the spool.
  • Ensure that the line is securely fastened in the notches and that it’s evenly wound with no overlaps or tangles.
  • Reattach the spool head cap back on and ensure it snaps into place securely.
  • If there’s any excess line sticking out beyond the spool, use your scissors to trim it neatly.
  • You can now safely reattach the battery to your Dewalt trimmer.

Uneven Cutting:

This problem arises if the Dewalt 20V Hedge Trimmer is not held steadily. The trimmer vibrates more or less because of its motor. As a result, the trimmer makes uneven cuts. The way to solve this problem is to hold the machine more steadily.

Loose Strings:

The strings of the Dewalt 20V Hedge Trimmer often get loose. Sometimes the situation can be fixed by cleaning it. Other times replacing the strings is the only solution. 

These are all the common problems found in the Dewalt 20v Hedge Trimmer. The solutions and fixes of these issues are also discussed here. The solutions are quite easy like removing the M12 Milwaukee battery.


Is 20v Enough For A Hedge Trimmer?

Yes, 20v is enough for a hedge trimmer. This voltage can supply the trimmer with enough power for cutting thick branches. A trimmer with 20v can easily cut branches with a thickness of ¾-inch. However, the size of the blade is also important besides trimmer voltage. 

Why Does The Battery Hedge Trimmer Keep Cutting Out? 

Your battery hedge trimmer can keep cutting out for several reasons. Anyway, the most common reason for this problem is a loose connection. Besides that, the battery can be weak and run out of juice within a short time. This issue can also be caused due to a clogged spark arrestor.

Is Higher Voltage Better For Cordless Hedge Trimmers?

Yes, a higher voltage is better for cordless hedge trimmers. The performance of the trimmers depends heavily on the voltage. Higher voltage means more power delivery. Also, the battery runs for a longer period with a high-voltage battery. So the efficiency increases with the increasing voltage. 


This is all on the topic of the Dewalt 20V Hedge Trimmer problems. Hopefully, now you can fix your Dewalt 20v trimmer without any issues and you won’t throw away your Dewalt 20v and buy a new one.

Please, write in the comments about your experience with Dewalt 20v.

Read also: How to disable Milwaukee one-key

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