[Ovmsdev] Request for Comments - Charge Bay Alert

Tom Saxton tom at idleloop.com
Wed Nov 20 03:18:09 HKT 2013

Casey Halverson, a Seattle-area LEAF owner developed a similar system prior
to June 4, 2012 (I don't have the original launch date, that's the date of
the first email I could find referencing it). Casey's system doesn't rely on
license plate numbers. You register your cell phone number and you get a
system ID number which you print on a sticker or card.


People then text your ID to the system's SMS number and that sets up an
anonymous 2-way communication channel via SMS between the caller and the
owner. Cathy suggested he could put a QR code on the sticker, but not every
smart phone can handle a QR code that sends a text message and/or different
phones need different codes. Each owner gets an ID instead of each car using
their license plate number as an ID. Using the license plate number doesn't
work in the US because license plate numbers aren't globally unique: you can
have the same license plate number in different states. For example, I know
there are duplicates of the custom plate I have on our Roadster: AMPITUP.
Further, I drive our car out of state.

I don't see how this type of system integrates with OVMS, but there is
another approach that came out of a conversation I had with a friend who
works at the Google campus in Kirkland, WA. They have two parking spots per
charging station and thus have to move charge cables around on a daily
basis. Their system is that if you need a charge but can't plug in when you
arrive, you pop open your charge port and put your Chargepoint card under
your windshield wiper. When an adjacent car completes a charge, someone
unplugs the full car, closes its charge port, moves the cable to a car that
needs a charge, and starts the session with the owner's card.

The system fails with the Model S because the J1772 adapter locks to the
port and forces the charge port door to stay open, so you can't tell if the
car is charged or not.

It's also a pain that you someone has to go physically check the cars and
also be an expert at reading all of the different ways the cars show their
SOC externally.

So, the idea was to have an app that displays the charge state of everyone
participating in the charger sharing. That's something that could be done
easily with OVMS, similar to how participating in a group allows anyone who
knows the group name to see your car's position.


From:  Paul Churchley <paul at churchley.org>
Reply-To:  OVMS Developers <ovmsdev at lists.teslaclub.hk>
Date:  Monday, November 18, 2013 at 7:58 AM
To:  OVMS Developers <ovmsdev at lists.teslaclub.hk>
Subject:  [Ovmsdev] Request for Comments - Charge Bay Alert

First, hello to everyone. I am a software/web developer in the UK. I own a
Nissan Leaf and a Vauxhall Ampera.

As more and more EVs get on the roads so the public charging locations are
going to become more and more busy. Waiting to charge might not be the norm
at the moment because there are still low numbers of EVs out there but as
they become more popular so the public charging bays will become congested
and having to wait while another car finishes its charge will become more
the norm.

Already we are seeing EV drivers leaving their mobile numbers on the dash so
that drivers of EVs that arrive later can call to let the driver of the
charging car know that someone is waiting to use the charger. They can then
ensure they return to the car as soon as the car is charged to unplug and
allow the newcomer to start their charge. Without this communication it is
very possible that the driver of the charging car may not know someone is
waiting and so may not return for some time after his car has completed its
charge. Unplugging a car that has completed its charge is sometimes possible
but in some jurisdictions this may be illegal and sometimes the charge post
fails to allow further charging if the car is unplugged without using the
original card. So we need an easy and simply way to contact the owner of a
charging EV to inform them someone is waiting.

Also, some people may not want to publicise their cell number on their dash
for security reasons.

About 18 months ago I developed a standalone web site that allowed an
arriving EV driver to send an SMS message containing the licence plate
number of the car charging in the bay and the web site would then look up
the licence on its database to get the mobile number of the owner and then
send a SMS message to that owner informing them that someone was waiting to
charge. They could then send an SMS back to the web site with an expected
return time. The web site would then SMS the waiting EV driver the expected
return time and optionally the charging drivers mobile number. Using this
system EV drivers could establish 2-way communication without any driver
having to make their mobile number public.

The only requirement was registration on the web site prior to use to allow
the mobile number look up to take place. Once registered a window sticker
was sent out with the web address showing that the car was registered.
Registration could be done via mobile too so an arriving driver could see
that the charging car was registered and could then register themselves
immediate and then use the system.

I bulk purchased SMS messages from a provider that provided a API so I could
send and receive SMS messages via PHP on the web site. I paid for these
myself for testing but I would imagine that there must be some registration
andor use fee to cover these and hosting costs. I wouldn't expect it to be
much though as the emphasis is on providing the service and not profit.

The system was tested in the UK but there simply were not enough EVs in the
UK at that time to justify having the system. Now things are getting busier
I wondered is such a system might be benefitial so I would like to ask for

I thought that now we have OVMS perhaps there would be scope to interface it
with OVMS in some way? I know that OVMS and Open Charge Map are potentially
interfaced so it would make sense to leverage these systems where

Any comments would be appreciated.

Paul Churchley

Bio: I am a self-employed software/web site developer of 30+ years. I have
PHP, mySQL and other programming skills and could contribute towards
developing such a system or perhaps developing similar functionality in
other systems such as OVMS.
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