Green means "available" so you would instinctively expect an empty spot
at a green light.
I would suggest a slight change to the meaning of the colors:
Red = charging (no matter how fast/slow)
Yellow = charging ended, spot should be vacated as soon as possible
(grace timer)
Green = charging and grace timer ended, spot is available (even if full
EV still plugged in).

Anybody parked in a "green light" spot is suceptible to ticketing and
Grace time can be tuned to match need/demand, with appropriate signage.

When a "yellow" charging space is vacated, an EV can immediately plug in
and turn the
spot to "Red" again.
If a spot next to the EV charging spot is available and an EV arrives
that urgently needs a charge,
it should be perfectly fine to unplug a "Yellow" or "Green" charger.
Preferably he leaves a note at the car, how to contact him and how long
he needs to charge
before it is OK to unplug when the official EV charging spot is in use

Note that it is possible to implement a max charging time with this as
Towards the end of the max charge time the light turns yellow and when
the charge time
has expired, it stops charging but may allow an additional grace time
before the light
turns green again and you should be on your way (or moved out of the
spot at least).
At companies with high contention for too few spaces, it makes sense to
force everyone
to switch during lunch time (for example max 4 hours charging).

Many EVs already announce how long charging is going to take, so it
should be
no surprise how long one can leave the car before it needs to be moved.
Obviously it is user friendly if the charging station sends you a txt
when charging ends
and the grace time starts.

-----Original Message-----
From: EV [] On Behalf Of EVDL
Administrator via EV
Sent: Wednesday, December 13, 2017 1:40 PM
To: Electric Vehicle Discussion List
Cc: EVDL Administrator
Subject: Re: [EVDL] Combating ICED EV parking spaces

On 13 Dec 2017 at 13:08, Lawrence Harris via EV wrote:

> I would love to see a big light on the top of the charge head that 
> goes green while charging, amber when the charger ramps down to the 
> end of charge and red when done.

Outstanding idea, but I'd recomment the exact opposite of the colors --
red for bulk charging, amber for absorption (last 20%), and green for

That's  because almost every other charger used on personal gadgets
(phones, cordless drills, and so on) uses those colors or something
similar. It's read for charging, green for done, and sometimes you get
yellow or flashing green during the absorption phase.  I don't think
I've ever seen any other charger that was lit up red when it was
finished, except for a couple that never changed color.

David Roden - Akron, Ohio, USA
EVDL Administrator

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