How Many Amps are in a Car Cigarette Lighter?

Ever wondered what can be connected to a car cigarette lighter? This article will show you exactly how to use your cigarette lighter to charge all your electronic devices.

A car cigarette lighter is a 12 volts 10 amps (DC) outlet but can range from 5 to 20 amps depending on your car’s wiring and fuse. Installing a larger fuse than specified will damage your car’s wiring, causing a significant repair bill and an unpleasant smell. 

A 12v car cigarette lighter can handle as much power as its fuse size. Cigarette lighters and all DC outlets in your car will always be 12 Volts to match your car’s 12v battery output.

How many watts in a car cigarette lighter?

A car cigarette lighter can produce anywhere from 60 to 240 watts of power output. The Wattage of your car’s cigarette lighter is controlled by a fuse that can be anywhere from 5 to 20 amps connected between the cigarette lighter and your car’s battery.

The table below shows the different wattages a cigarette lighter can produce depending on its fuse. You don’t need to worry about voltage as it is always 12 volts of direct current.

For a 12v cigarette lighter or 12v accessory outletMaximum Power Output
Specified fuse amperageWatts = 12v x DC Amps
5 amps60 watts Power Output
10 amps120 watts Power Output
15 amps180 watts Power Output 
20 amps240 watts Power Output 

Keep in mind that this table shows peak power. Continuous power is a lot less due to heat loss through the wires and the inverter’s consumption. In the following table, you will also see how much power you can get when connecting an inverter for different time periods. 

What happens if you use a bigger fuse?

Using a fuse with the wrong amperage (namely a higher one) will permanently damage your car’s wiring and cause a large repair bill. A fuse is intended to be the weakest point in a circuit to take the hit first in case of increased current. Installing a larger fuse makes your wiring weaker than the fuse itself and leaves the car circuit prone to burn before the fuse can save it.

What fuse size for a car cigarette lighter?

A typical car cigarette lighter or 12v accessory outlet can provide 120 watts of maximum power output and not surpass a total of 10 amps. Drawing current any higher than 10 amps will result in a blown fuse.

On the other hand, Trucks sometimes have a regular low amp cigarette lighter and a 12v accessory outlet with a higher amperage for heavier loads (commonly confused for a cigarette lighter). Again, check your car’s manual!

The most common fuse size for cigarette lighters is 10 amps, and the least common is 20 amps.

You should check your car’s manual, check with a car electrician, or ask your dealership to determine your cigarette lighter’s specified amperage.

Also, if you are a bit of a handyman, you can pop the fuse box. It will take you no more than 10 seconds! 

Always keep some spare fuses in your car as you will certainly sometimes blow a fuse by mistake.

Fuses are cheap so get an assortment kit for a few bucks with your inverter on amazon. 

It is essential to note that a fuse protects your car wiring and not the cigarette lighter itself. Also, pulling the fuse’s maximum current (amperage) for a prolonged period might damage the cigarette lighter. It is mainly built to heat a coil (at high amperage) for 30 seconds. The contacts on are usually very flimsy and will not sustain high amperage and power for a long time. 

What does a car power inverter do?

A car power inverter takes your car’s 12v battery direct current and transforms it into a usable 120v AC (found at home) through a regular wall outlet built on the inverter. So you can now plug and charge electronic devices by borrowing some power from your car’s battery.

How to choose a cigarette lighter power inverter for your car?

  • Wattage

The standard 300w that many people buy (myself included) carries a risk of blowing your car’s fuse, but it also saves the inverter from blowing its own fuse. As you’ve seen in the very first table, a standard cigarette lighter outlet can produce (12v x 10 amps) 120 watts, and you can use about 85% of that power (leaves you with about 100 watts of power available to you). Hooking up an inverter with a power output higher than your cigarette lighter fuse will leave you in the danger of accidentally plugging anything higher than what the car fuse can handle.

  • Wave form: A pure-sine wave or modified-sine wave (square wave).

Pure-sine wave is the waveform found at home in your 120v wall outlet. Many devices need a pure-sine waveform to function correctly, and many others don’t. The point here is that it is not worth saving a few bucks because, at some point, you’ll realize that your power outlet is useless in an emergency. A typical example is trying to plug a CPAP which will probably not work and might damage your unit. Moreover, sensitive electronics such as laptops and cell phones need a pure sine wave inverter.

  • Fuse: for over current over voltage and fluctutaions

Much like your car’s wiring is protected with a fuse, make sure your inverter has its own built-in fuse to protect itself from overload and many other things that may go wrong while it is in operation.

  • Number of 120v outlets

This one is pretty obvious; the more outlets, the better. Yet, remember that more outlets also put you at the risk of mistakenly overloading your cigarette lighter wiring or even your inverter.

  • Number USB outlets

We all love USB outlets. They can charge just about any of our modern devices. So this is definitely; the more, the better.

  • Cooling and Build

An inverter will produce a significant amount of heat during operation. Ensure your inverter has a proper cooling system with fans and heavy metal construction to dissipate heat.

I have been through many inverters and highly recommend going with BESTEK’s Pure-Sine wave inverters (link to their store on amazon). My pick is the Bestek 300w which comes with 2 regular wall outlets, 2 USB charging ports, but more importantly, a 40 amp fuse to protect the device itself.

How to avoid overloading your car’s cigarette lighter outlet?

To avoid overloading your inverter and car cigarette lighter, look at the label of every device you intend to connect. Then, look for the OUTPUT on your device and multiply the DC voltage by the DC amps rating to get the Wattage.  

A label on a laptop charger will look like this:

INPUT: 100-240V~50-60HZ 1.8A
OUTPUT: 19V3.42A     

Not only does it explicitly say 65w, but you can also look at the output on any device and figure out the Wattage. In this case, 19volts x 3.42amps = 64.98, which is 65 watts that you can safely plug into your inverter.

You can now use this table below to figure out how long you can use any device. In general, you are good to go with most low-power electronics.

Personal rant here for the next few lines, so feel free to skip to the next title:

People always ask about amperage and forget that amps and volts constitute power. It would be best if you compare power and not only amps. Amps on a 19v charger are different than amps on a 12v charger. It’s like comparing apples and oranges.

Amps can be compared when the voltage and the current type (AC or DC) are the same. Like at home where the voltage is 120v and the current is AC.

On a side note, if we go back to our laptop charger example:
1.8 AC Amps (on the label) on the input side does not mean it pulls 1.8A. The input on the label is a generalization with a comfortable margin for a range of 100 to 240 volts! So don’t try to compare your AC Amps but rather the Watts.

Now, if you are bent on knowing the AC amps, you can divide the 65w that the device needs by your home AC current, which is 120v to get 0.5 AC amps that this device is actually drawing from your household outlet (far less from the stated 1.8 AC amps on the label!)

Before using your cigarette lighter inverter:

  1. Start your car engine and keep it running (to avoid depleting your battery).
  2. Inspect your cigarette lighter to make sure it is free of debris or any dirt at the base which could act as an insulator and deteriorate conductivity.
  3. Connect the inverter without any loads and turn it on.
  4. Connect your devices (making sure you do not surpass the specified wattage of your cigarette lighter fuse).

What can you safely plug into a cigarette lighter inverter?

  1. Cell phones
  2. Cell phone battery banks
  3. Laptops
  4. Dash cams
  5. Small TVs
  6. DVD players
  7. Handhed gaming consoles chargers
  8. CPAP machines
  9. Most handheld electronics are safe to connect to an inverter

People complain about damaged wiring, blown fuses, and ill-functioning inverters, but almost all of these issues can be traced back to overloading and wrong sizing of the inverter. So make sure you do the very little needed math and use the table below to figure out how long you can plug your devices into your car’s cigarette lighter inverter.

How many watts in a cigarette lighter with an inverter?

According to the cigarette lighter’s fuse amperage, here is how much power your inverter can provide for different time periods.

Fuse DC Amps for
Car Cigarette Lighter
Maximum Inverter Power
Output for Peaks
(85% of stated power)
5 DC Amps51 watts
10 DC Amps102 watts
15 DC Amps153 watts
20 DC Amps204 watts
Fuse DC Amps for
Car Cigarette Lighter
Maximum Inverter Power
Output for 20 minutes
(70% of stated power)
5 DC Amps42 watts
10 DC Amps84 watts
15 DC Amps126 watts
20 DC Amps168 watts
Fuse DC Amps for
Car Cigarette Lighter
Maximum Inverter Power
Output for 1 hour
(65% of stated power)
5 DC Amps39 watts
10 DC Amps78 watts
15 DC Amps117 watts
20 DC Amps156 watts
Fuse DC Amps for
Car Cigarette Lighter
Maximum Inverter Power
Output for continuous use
(50% of stated power)
5 DC Amps30 watts
10 DC Amps60 watts
15 DC Amps90 watts
20 DC Amps120 watts

Based on my user experience, I have concluded that a cigarette lighter can be used as a power 120v outlet (colloquially known as 110v) but can only sustain about half of its specified amperage for prolonged use.  

Also, as a general rule, inverters need approximately 1 amp of DC input for every 10 watts of AC output it produces. Or a more straightforward way of seeing things is to use a generally accepted average 85% inverter inefficiency, which means that you lose about 15% power to convert DC to AC.

Do power inverters drain your car battery?

A power inverter will drain your battery if directly connected to the battery (not through a cigarette lighter or a 12v accessory power outlet). An outlet has a fuse that will blow if you draw too much current, but a direct connection could lead you to install an oversized inverter that will pull more power than being replenished by the car’s alternator. 

Can you leave a power inverter plugged in a cigarette lighter?

Usually, you can leave an inverter plugged in at all times as 12v power outlets won’t provide power if the ignition is off. However, it might not be the case in older cars. If you are unsure, plug your phone in the outlet and see if it continues charging when your engine is off. 

What is the difference between a car cigarette lighter and a 12v accessory power outlet?

Are all cigarette lighter sockets the same?

Cigarette lighters have served as lighters with heating coil and accessory outlets for many years. Nowadays, we can only find 12v accessory power outlets in more recent cars, which visually seem very similar to the cigarette lighter cylindrical outlet. However, these 12v outlets are more efficient as they are not built to heat a coil in a few seconds but rather to provide a steady current. 12v accessory outlets also have a better fit to improve connectivity and conductivity but do not double as cigarette lighters.

Cigarette lighters are the older standard for 12v outlets in cars. A cigarette lighter is slightly larger, has a poor fit, and is less reliable when connecting your accessories.   

Also, as a safety measure in newer cars, cigarette lighters / 12v accessory power outlets only provide power when the engine is running to avoid draining your battery if any devices are forgetfully left plugged in. This ensures that you can always start your car. 

How many amps (DC) a car cigarette lighter draws from a car battery?

Using an inverter connected to a 12v cigarette lighter or 12v car accessory outlet:

The table considers the Total Load, which means all devices are simultaneously connected to the inverter. (120v outlet, all USB connections, etc.)

1. Cigarette lighter fuse2. Maximum Inverter Draw for Peaks (85%)3. Inverter draw for 20 minutes (70%)4. Inverter draw for 1 hour (65%)5. Inverter Continuous Draw (50%)
5 amps4.25 DC amps3.5 DC amps3.25 DC amps2.5 DC amps
10 amps8.5 DC amps7 DC amps6.5 DC amps5 DC amps
15 amps12.75 DC amps10.5 DC amps9.75 DC amps7.5 DC amps
20 amps4.25 DC amps14 DC amps13 DC amps10 DC amps

Table explanation:

  1. Fuse amperage for a 12v car cigarette lighter or a 12v car accessory outlet. 
  1. This is the maximum current the inverter should be required to draw on the car battery during peaks of a maximum of half a second. The maximum inverter draw for peaks is calculated on a widely accepted average of 85% inverter inefficiency. This is because the inverter will also need some power to convert DC to AC. The amperage here is discounted at 15% to account for the inverter’s losses during its operation. 
  1. Inverter draw on battery for 20 minutes. This should be about 70% of the inverter’s output rating. 
  1. Inverter draw on battery for 1 hour. This should be about 65% of the inverter output rating.
  1. Inverter continuous draw on a car battery. This should be about 50% of the inverter output rating.

Finally, do NOT believe any of the false advertising claiming that you can connect heating devices as you can see that overall useful DC amperage is relatively low for a car’s 12v cigarette lighter or 12v car accessory outlet.