What Is The Difference Between A Car Adapter and an Airline Adapter?
The term "airline" adapter describes a power adapter that is compatible with 4-pin Empower type power outlets. Empower is the brand name of the system that was installed in the airline seats. This system supplies 15V DC and up to 75W maximum per outlet. For an adapter to be called "airline" it must have the 4-pin connector, be able to accept 15V input, and cannot be rated higher than 75W. Car adapters that meet these electrical requirements can be made "airline" adapters by including an adapter that converts from a standard lighter outlet to the 4-pin connector.
Many airlines have begun to install customized versions of the Empower system that use standard car lighter sockets instead of the 4-pin sockets. These systems allow you to use most standard car adapters. The one limitition that remains is the 75W maximum power per outlet.
Empower and even most of the customized systems have the 75W maximum limit. If this limit is exceeded the outlet will trip a breaker and shut off. The airline seat system impose this limitation to ensure that the generators on the plane can make enough power for all of the seats and for safety reasons. Higher power outlets pose a greater fire risk. Due to this limitation laptops that need more than 75W cannot be powered using airline seat outlets.
The type, specifications, and availability of power outlets can vary greatly between airlines, aircraft type, and seat locations. You should check with your airline to determine the availability and requirements of the power outlets available on your specific flight.
Car Adapter Usage Tips
- Do not start the car with the adapter connected. Starting the car drops the battery voltage very low which causes a spike in current (amps) to try to make up the difference. It is common for this rush of extra current to blow fuses.
- Make sure that the adapter has proper cooling. The adapter should not be in direct sunlight and it should be placed in a spot that has open air flow around the unit. Do no bury the adapter inside of a console, below the seat, etc. Car adapters have thermal protection that will shutdown the adapter if it overheats. The adatper will begin to work again after cooling.
- Use while the engine is running whenever possible. In addition to preventing battery drain, running the engine increases the voltage which allows the adapter to work more efficiently
Why Does The Adapter Blow The Fuse?
A fuse blows whenever the power demand is more than what is available. The total amount of power is determined by both the Voltage and the Current (amps). Most car lighter outlets are rated at 10A. The voltage varies based upon the amount of charge in the battery and also if the car is running. When the car is not running the voltage can be as low as 10V and when the car is running the voltage can go up to 15V. This translates into a maximum power of 120W to 150W for most vehicles.
The average laptop requires below 90W. These laptops are well within the limits and usually will not have any issues unless you are connecting multiple devices to the same circuit. One note is that some vehicles have the lighter outlet on the same circuit as other equipment in the car. In these cases, the total of the laptop and the other equipment has to be within the limits. The vehicle's owners manual will typically list the items on each fuse. This should show if there is any other equipment that shares the same fuse with the lighter outlet.
The power limitations are often a problem with very large desktop replacement laptops. These laptops can require up to 240W. This very large power demand requires a special circuit or a direct connection to the battery in order to supply enough power.
There is a fuse in the adapter plug itself. The fuse can be accessed by unscrewing the center tip of the lighter plug.