20V vs 40V Trimmer | What’s the Difference?

The Everlasting questions:

  • What’s the difference between a 20v and a 40v trimmer?
  • Which grass trimmer equipment should I buy?
  • Choose the 20V or 40V?

To answer this question, we must first ask ourselves, what use will I give to this cordless system? The wireless tools are much more versatile than those that use a cord. Even, much more ‘clean’ than its similes to internal combustion; and its maintenance is much faster and cheaper. However, within the classification of these tools, there are several types that will depend on the power, the size and even the weight.

If you are wondering, can you use a 40v battery in a 20v tool? Check out the detailed article on myhomedwelling.com.

How does a Grass Trimmer work?

The grass trimmer works with a motor either internal combustion or electric. The engine is connected to a long and thin bar that ends in the cutting system that acts as a transmission or gimbal. These bars can be straight and both the trunk of the engine and the bar itself are provided with individual handles or double handlebar which is held with both hands to distribute the weight better and thus obtain better control.

At the end of the bar there is a rotating device in charge of cutting, normally of ABS in which a nylon thread of different thickness is used. For heavier work, steel pieces with different shapes are used, the most common being 3 or 4-pointed pieces. The grass trimmers can also come with a harness or backpack to secure it to the body and facilitate its manipulation by dividing the weight.

With an accelerator added that regulates the rotation speed of the head, this is turned into the best tool for your backyard.

However, Safety first of all!

Because it is a tool with a rotating machine, it turns it into a device with a certain level of risk, which we must consider and take some safety measures:

1. The machine must have a protector (or dust cover) on the back to prevent waste from reaching the user. In addition to this, the user must have appropriate clothing, such as:

  • Gardener’s boots
  • Apron
  • Thick cloth pants
  • Full face protection helmet
  • Anti-slip gloves

2. Due to the fact that normally the front part is not protected, the user must pay attention to people who may be nearby, fragile objects, vehicles, etc.

In a backyard, there are usually many objects that can be fragile and are not exempt from damage by the use of a grass trimmer. Therefore it is also recommended that one or two helpers be placed with a protective blanket in front of the user (about 3 meters of prudential distance) using their respective safety implements, which would function as a projectile-catching curtain and thus avoid collateral damage.

Now, to the point – 20v vs 40v Trimmers

Saying the above, we can talk about the advantages and disadvantages of a grass trimmer, either 20V or 40V.

In general, the higher the voltage, the more power and the higher the cutting speed. The 40V motors that have these machines are more efficient because they do the job better with a consumption lower than its equivalent of 20V.

However, we must also consider the price, the weight and the size of the equipment. The lower the voltage, the smaller the blades / nylon of the equipment can be, although not necessarily because there are brushless motors that are capable of increasing the power.

In any case, if the size is not relevant, then it is better to use larger tools with larger operating voltages as well. The autonomy also plays a preponderant role as well as the performance of the device.

Being more specific:


As we are going to focus on electric trimmers, it is necessary to talk about certain characteristics that electric motors have. For example, the unit of measurement of power on electrical equipment is the watt.

The more power in watts, the higher the cutting speed and therefore, the more efficient the operation. However, there may be applications where a low speed is required and thus the use of a low voltage machine is more convenient and enough.

Depending on the area to be cut (if it is a small or large back yard), the decision to acquire a 20V or 40V grass trimmer would be directly proportional to the size (and time) of that area

Size and weight

The 40V grass cutting machines are much larger and heavier and therefore less handy. For example, a short 20V grass trimmer can weigh up to half (or less) than its equivalent of 40V.

In this section it is also important to highlight the physical conditions of the user, the frequency of cutting the backyard area, the type of grass, the geometry of the ground, among others. As well as the place of storage of the device.

Battery technology

The useful life of the battery charge is a relevant issue in terms of this type of equipment, because they can usually be operated in places where it is not easy to make a quick ‘recharge’ of the batteries.

If we calculate the life of the batteries by dividing the amount of energy they can store, between the power consumption of the equipment (W-H / W) we can see that the higher voltage equipment will be much more efficient in terms of available energy and its duty life will be much longer than 20V equipment.

The hurry or speed with which the grass cutting should be done is important here, since, of course, a 20V battery has a shorter usage time than a 40V battery.

Also the dimensions of the terrain to be cut on the backyard are important.

Charging Technology

The higher the battery voltage, the longer the charging time. Also, the necessary amperage of charge for a 40V battery will always be greater than for a 20V battery. Evidently this comes from an AC source which also represents an inherent cost of charging.


It is evident that the price of a 40V equipment will always be higher than a 20V price. In general terms, for equipment of the same brand, the prices can be in the order of 2:1. And if we go to the spare parts market, the batteries are also much more expensive, practically in that same proportion.

Read Our Top 10 Best Battery Powered Grass Trimmers Article

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