Automobile/Airline Adapters

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There have been a few instances of airline power adapters not working with in-seat power sources. This can happen when an adapter is required to produce the fully rated 70 watts to fast charge the internal laptop battery but the in-seat power system is not designed to produce that much power. With an adapter efficiency of 90%, the 70-watt load tries to pull 78 watts from the in-seat power unit, and it safely shuts down. The safety circuits in the adapter also sense the overload and also safely shut down.
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This can happen with any of the in-seat power systems that have current limited outputs of around 5 amps (Note that 5 amps at 15 volts = 75 watts).
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This can also happen with any brand of power adapter and with any laptop that draws up to 70 watts.Many of the in-seat power systems were designed when laptops used between 54 and 60 watts. The need for higher power was not foreseen by the airlines.
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Solutions:

1. Turn off the laptop before plugging the adapter into the in-seat power system. Most laptops will draw less than 70 watts when only charging the battery. Allow the battery to charge for 15 to 20 minutes then try to operate while it continues to charge at a somewhat lower level.
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2. Remove the laptop battery before plugging the adapter into the in-seat power. The operating power of a laptop is far less than the combined operating and charging power. Note that without the internal battery any interruption in in-seat power will cause a loss of unsaved data.
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