RC Car Rapid-Charger Demo Project

[garygid]

I am considering building a Rapid-Charger miniature Demonstration:

Envision an RC model car, a model mini-QC type device, and
perhaps a model house.

Plug the house into the grid, the mini-QC into the house, and charge
the car. Or, remove the grid and have the car power the house? :shock:

1. The model house could be almost anything, but fairly durable
plastic might be best, not expensive, perhaps with a Japanese
type architecture, but anything would work, perhaps a foot high.

Grid power to the house might be 12v DC, with LED lights in the house.
The 12v is from a typical 1000 ma UL AC Adapter, to keep everything safe
in the demo. Depending upon the design details, AC might be used.

A display panel in the roof of the house might monitor power in,
house usage, and EV-charging power flow. It might also turn
home devices on and off, to vary the load.

2. A model car, perhaps 6 to 8 inches high, preferably a LEAF or look-alike,
but an iMiEV would also be good, or anything else could still get the
EV message across. Possibly it would be easier to find a model
resembling the RAV4EV, or even the Tesla S.

An inexpensive RC car with a motor, a rechargeable battery, sufficient
room inside to add an Arduino Due with a proto shield (or two) and
allow a 3.2" or 3.5" touch display to stick through a rectangular opening
cut in the roof, and a remote control for driving the model car would
be ideal. The Due would be programmed to simulate a QC vehicle.
I am working on programming that now.

We could add a miniature QC-type socket, to accept a mini-Jolomo
plug with the standard 9 conductors, and then simulate, or
possibly even actuall, "Rapid-Charge" the traction battery.

3. A plastic box to represent a mini-QC device, perhaps larger than scale,
with a multi-wire cable to a mini-Jolomo plug, and enough room inside
for another Arduino Due, shields, and a "user-control" display. A
3-conductor miniature cable would get power from the house.

For better demonstration, the display probably needs to be
on the top surface of this miniature mini-QC device.

Initially this could simply be a plastic box with some paste-on
computer-printed artwork, but we might be able to find some
suitable container with some interesting shape, rounded corners,
etc. that could be re-purposed.

----------
Initially this demo, without the house, would simulate the
mini-QC process, and eventually actually charge the RC car.

Later, when we manage to make a model of the
car-to-home device that is available in Japan,
we could demonstrate powering the house
from the car.

 

[garygid]

For the mini-Jolomo plug, about 1/4 scale, for a 3/4" OD socket, and about
0.7" OD plug might work, using two 2x2 0.1" center standard board header
connectors for the 7 control signals, and two more 1x1 headers for the "power" pins.

Pins arranged something like this:

         o
      o     x
         o
  0             0 
         o
      o     o
         o

The 2x2 headers are 0.2" square, or about 0.28" on the diagonal, so the
two adjacent would be 0.56", then adding another 0.05" thickness for the
outer wall of the plug makes it about 0.66 diameter.

The socket might be 0.75 outer diameter, and be mounted in the
side of the model car, or possibly elsewhere, like the hood, depending
upon the model chosen.

 

[garygid]

In any case, I am working on the Due-based uP components,
even if we don't make this demonstration model.

 

[garygid]

For a "model" connector, perhaps a 2x5 or 2x6 right angle male header
coming off the Due proto board, going to two 2x4 headers (with male pins)
side by side in a mini-Jolomo plug with the pins arranged like this:
(looking at the end of the plug)

         GP
      QR    x    
   x     EC    x   
 PP    x     x     PM
   x     GD    x
      CH    CL
         BR

(my guesses/interpretations, assuming that I got it correct, YMMV)
Use at your own risk.

GP = Ground, Protective
QR = QC Ready, QC applies 12v
EC = Enable Charger (permission to charge), car pulls to ground.
PP = Power, DC Plus, isolated
PM = Power, DC Minus, isolated
GD = Ground, Disable car motion, Plug Proximity
CH = CAN-High
CL = CAN-Low
BR = Enable Battery Relay closure, to begin charging, Ground from QC

Patterned after the info in these documents:
The interface: http://chademo.com/05_interface.html" onclick="window.open(this.href);return false;
The protocol: http://chademo.com/05_protocol.html" onclick="window.open(this.href);return false;

Apparently this is the sequence of opperation (guesses) :

GP and GD are grounded when the plug is inserted.
CH and CL are biased but not yet active.
PP and PM are unpowered, but will carry the charging current.

That leaves just 3 control lines (again my assumptions):

QR, the QC applies 12v if/when it is ready/available to do charging.
... (The car responds by starting CAN communication, sending car requirements.)
... (QC responds with charger capabilities.)

EC, the car pulls this line to ground to enable charging prestart testing.
... After successful pre-charging tests...

BR, the QC connects this line to ground to participate in closing the Battery Relay.
... The car closes the Battery Relay to "expose" the car's battery pack HV leads.
... (The car requests current, in amps.)
... (The QC "follows" the request, and reports its status.)

If there are errors here, please let me know.

 

[garygid]

So, for the interface control, it appears that:

The QC should have a user-operated Start and Stop function ("buttons").

Presumably, the QC has a way of detecting that the QC Plug is
mated with the car's QC socket, and that mating is necessary to
enable the Start button. This mating might require a "plug inserted"
signal, and a "lock" control, with a "locked" LED indicator.

Detecting voltage on the BR pin might be used as an "inserted"
indication, but perhaps the document describing the plug will
reveal more?

The QC needs to be able to supply 12v (current requirement is xxx ma) on QR.
Unknown short circuit protection, or series resistance.
Presumably this voltage is supplied only after the user presses the Start button.

The QC needs to be able to sink the xxx ma with the BR pin.

The QC needs to detect the EC line from the car being pulled to ground.

The QC needs to handle 2-way CAN communication.
The bus appears to be 500,000 bits per second, similar to
the other 3 CAN buses in the LEAF.