Circular saws are powered by electricity. It can be corded or cordless. Cordless circular saws are powered by Li-Ion batteries and corded saws can directly plug into the power source with a suitable power cord. Circular saw power can be calculated by its voltage and current. So let’s see how many watts does a circular saw use?
Circular saw watts consumption depends on the current and voltage requirement of the motor. When it starts, 2300W is required, and while it is running, 1400W is required for the corded circular saws. In cordless circular saws, It will be 30-180 watts of power will consume.
When using a circular saw, we should know how to optimize the power in order to use the tool long run. When you select a circular saw, you should know the watt consumption of the circular saw. You must know about the voltage, current, and power factors for the corded circular saws.
For the cordless, you should know the battery capacity and voltage. By using this guide you can learn all in detail about circular saw power consumption in detail. So let’s move on!
How to Measure Circular Saw Watt Consumption?
The circular saw watts can be measured by their voltage and current. The power consumption of any electronic device can be measured by multiplying its voltage and current. The cost of the circular saw depends on the power consumption of the tool.
If it is AC operated tool you have to know the power factors. If it is operated by the battery, you should know the battery capacity and voltage. The power is measured by the “watt”. So let’s see how we can measure this.
Power of any electronic device = Voltage × Current (P=V × I)
For the AC Operated Devices
Power = Voltage × Current × Power Factor = (P=V×I×PF)
For the Battery Operated Devices
Power = Capacity × Voltage = (P=V × I)
This is the simple watt calculation for electronic devices.
Power Factor – The power factor is defined as the ratio of real power to apparent power PF = kW / kVA. You should have the technical knowledge to measure the power factor. So I would like to recommend you take the power factor as 0.85. It can be changed from device to device.
AC to DC Conversion
Most saw motors are designed with DC motors because they are easier and cheaper to control than AC motors. But converting AC to DC will waste some watts. So it is better to use 0.95 as a Power factor for the watt calculation of the circular saw.
Example 01 – Corded Circular Saws (For AC Motors)
What is power consumption in watts for the corded circular saw when the power factor is 0.85 and the phase current is 4A and the RMS voltage supply is 110V?
P = 0.95 × 4A × 110V = 418W
Example 02 – Cordless Circular Saws
What is power consumption in watts for the cordless circular saw when the capacity is 4 Amh, and the voltage is 20V?
P = 20 × 4 = 80W
How Many Watts Does a Circular Saw Use?
Normally corded circular saws need 2300 watts to startup the circular saw and 1400 watts to run the circular saw continuously. Cordless circular saws require 4–6 times the full load current unless you start it unloaded. The current supply needs to be capable of supplying that for a few seconds or the motor will not start or will take too long to get up to speed.
| Voltage | Current | Watts |
| 20 Cordless | 1.5Ah | 30W |
| 20 Cordless | 2 Ah | 40W |
| 20 Cordless | 3 Ah | 60W |
| 20 Cordless | 4 Ah | 80W |
| 20 Cordless | 6 Ah | 120W |
| 120 Corded | 10 Amp | 1140W |
| 120 Corded | 15 Amp | 1710W |
** Take the power factor as 0.95
How Much Will It Cost for Circular Saw Watts?
When we use a circular saw, it is great to know how much will it cost to circular saw power. In the USA we have to pay 10.66 cents per kilowatt-hour. So let’s see how much you have to cost for the electricity due to circular saw usage.
Let’s imagine a circular saw is needed to use 2 hours per week. So a total of 8 hours will use a circular saw, and it will cost like this.
| Voltage and Current | Watts | Cost |
| 20V, 1.5 Amh | 240 | 0.026 |
| 20V, 2 Amh | 320 | 0.035 |
| 20V, 3 Amh | 480 | 0.052 |
| 2V, 4 Amh | 640 | 0.070 |
| 20V, 6 Amh | 940 | 0.103 |
| 120V,10A | 9600 | 1.05 |
| 120V,15A | 14400 | 1.58 |
How Many Watts Does a 15 amp Saw Use?
When a 15 amp circular saw is used with 120 voltage, it will consume 1800 watts. If there is a 0.95 power factor, it will be 1710 watts.
When the current is increased, motor torque will increase automatically. We can buy both 10 amp and 15 amp tools in the market. If you buy a 7-1/4 saw blade, it is highly recommended you buy a 15 amp circular saw. Because the higher saw blade will bind with the workpiece due to friction. So higher torque will solve this kind of problem.
How Many Watts Does it Need for a Cordless Circular Saw?
Cordless circular saw watts requirements depend on the battery capacity and voltage. If you use a 20V battery with 1.5 amh will produce 30 Watts. If you use higher capacity batteries such as 3 Amh, 6 Amh, you can have 60W and 120W easily.
Cordless circular saws have limited performance due to their battery capacity. When the battery is over, We have to stop the work or replace a new one. So keep 2-3 additional saw batteries when you use a cordless circular saw in your workplace.
How Many Volts Does a Circular Saw Use?
A corded circular saw will use 120 volts, and a cordless circular saw uses a range of voltages such as 20V,36V, or 56V according to the design voltage of the circular saw. Voltage directly affects the saw blade spinning rate. When the voltage difference is high, electronics can move fastly, and the result will be a higher spinning rate with lower torque.
When the voltage is high, its torque will reduce, and the result will be increased current draw, which can cause the motor coils to overheat, decreasing motor life. So It is better to use the circular saw under recommended voltage. Do not use it higher or lower voltage.
How Many amps Does a Circular Saw Use?
A corded circular saw uses 10 – 15 amps of current, and cordless circular saws use 1.5-10 amp current while it is running. When a motor is starting it will require more current in order to work against the additional forces. When the current is increased, motor torque can be increased.
When we use larger blade sizes, we will need more current.
If the circular motor is rated as 15 Amps it will not use 15 Amp every time. When it starts, it can use 15 Amps. During the running process, it will need 8-10 Amps. When the load is increased Amps will increase rapidly in order to increase the torque of the motor.
When we consider the cordless circular saws, there are Li-Ion rechargeable batteries. These batteries come with various capacities. It can be 1.5-10 Amh. If you use a 2 Amh battery. You can use 1 ampere in 2 tours or 2 amperes in 1 hour.
So higher capacity battery is better than a lower capacity. Because it will remain a long time without discharging it.
How to Reduce the Circular Saw Watts?
You can reduce the circular saw watts by following these things.
- Sharp saw blade,
- Clean saw blade,
- A suitable number of teeth
- Proper cutting speed.
If the circular saw is binding with the workpiece, watts will be increased due to prevent clogging in the workpiece.
If the circular saw is sparking or brushes are worn and no regular services it will require more watts in order to act against the inside friction.
What Size Generator Do I Need to Run a Circular Saw?
If your circular saw starting watt is 2400 watts you will need a more than 5000W generator to run the circular saw. Normally, starting power is higher than its running power. So it is essential to choose a high power generator as it can produce more than starting watts of a circular saw.
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