The arrival of modern electric cars and public charging infrastructure has brought a whole range of etiquette issues to the fore.
Electric cars' long charging times, and the limited availability of parking spaces with access to charging stations, can sometimes create a bit of tension.
It's not unheard of for drivers to unplug other cars when they can't find a charging station of their own--whether those cars are done charging or not.
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There's been much discussion about what to do in these situations, but now there's a simple solution.
A hanger sign marked "Do Not Unplug" on one side and "OK To Unplug" on the other is now available through Take Charge and Go (via Tom Moloughney's BMW i3 blog).
The signs are shaped like the "Do Not Disturb" signs you'll find in hotels, and they slip over a standard J1772 charging connector.
There's even space on the "Do Not Unplug" side in which the driver can write the time when a car will be finished charging, along with a phone number.
Both sides of the card also have a list of charging-etiquette tips that should encourage peaceful relations with other drivers.
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They advise electric-car owners not to park in a charging space if they aren't actually charging, to limit their charging times, and--of course--never to unplug another car while it's charging.
One more feature is a QR code which, along with a link to the Take Charge and Go website, provides further information on public charging.
The signs are available through Take Charge and Go individually for $2.49 each, or in a 10-pack for $19.99.
Note that some electric cars have locking mechanisms that prevent them from being unplugged until charging is complete--unless the key fob is nearby.
Only some plug-in cars have this feature, but it could create a minor sticking point in an otherwise straightforward system of owners giving permission to unplug after a certain time or charge level is reached.