Mini-QC Rapid-Charger (RC) Project for LEAF QC Port

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garygid said:
Since the Chademo vehicle expects the input current (thus power) to follow
its requested current, and there "appears" to be no provision for providing
substantially less (or more) than requested by the car, or abort the charging
session.

True, there is a negotiation (kind of a mating ritual) at the beginning of the session,
before any charging actually starts, and part of that is the QC machine saying how
much voltage and current it can supply, and then the car wanting a demonstration
of the voltage "dance" from the QC machine. If the ritual is satisfactory (to both
sides), charging begins with a relatively fast, but controlled (by the car) ramp up
of the charging current, done at the present battery voltage, of course.
Click to expand...

The charger sends out the maximum current avalible every 100ms (along with its other parameters). I haven't seen any that dynamically adjust during a session though. It should be possible.

The car requests the charger do an insulation test by having the charger ramp to 500v while looking for leakage current with the contactor to the battery open. After no leakage current is detected (and the charger goes to 0v), the car closes the contactor and the charger ramps up.
 
KillaWhat said:
picked up on an earlier comment indicating the car requests a particular voltage but thought that was strange. I would have though the car would request a particular current (and just have a max voltage safety setting)
Click to expand...

I have just started looking at the DCQC, so If I'm off here , my apologies.
I have watched my meter system while the Car was QC'ing, and it seems to me that it "pivots" around the Max KW output of the charger.

As the Voltage of the charging pack increases, the current output decreases accordingly.
I take it that this is why it takes almost no time to get to 80%, but it has been noted that QC'ing beyond that is not time effective.


That's not accurate for the 2013's. I can QC to 90% in 30mins. or less.

So I assume that the system is adjusting the output VOLTAGE to remain above the pack voltage, but not drastically so.
Click to expand...
 
Are you planning to build a DC source from scratch or are you going to use an off-the-shelf component?

This is very exciting! I think it would great if the system could take AC input e.g. from a regular J1772 EVSE .
 
I take it that this is why it takes almost no time to get to 80%, but it has been noted that QC'ing beyond that is not time effective.


That's not accurate for the 2013's. I can QC to 90% in 30mins. or less.
Click to expand...

I don't know everything about how the DCQC is controlled. YET

The level 2 is completely controlled by the system onboard the vehicle.
I have built some custom L2 EVSE, and I can tell you, there is NO intelligence in there.
It's a glorified Light switch with the ability to abort if some criteria occur.

The L3 charging on the other hand seems to be controlled by the external charger, with the car reporting some data that the Chademo can use to make adjustments.

I doubt that the 2013 has any significant changes in the DC charging system that would affect it's operation over the 2012 design.

I have a pretty nice metering system, and can watch the car's internal data as it charges.
The only DCQC I have access to is a Blink Chademo, and it will not offer me the option to go beyond 80%.
(anybody know what that is about?)

My car can charge from 25% to what the charger thinks is 80% in 14 minutes.
The initial current is very high, but at 13 minutes it is down to 25% of what it was when I initiated the charge.

I'm not holding you to the 30 minute estimate number, but lets assume for now that it's accurate.
That would mean that it took as long to go from 25% to 80% as it would to go from 80% to 90%.

This is in keeping with that tapering as voltage increases I noted, even if the times are not set in stone.

Just a note: The Blink I have access to stops my charge at 72% (by meter) even though it thinks its 80% (showing on the Blink)
I'm interested to see if that changes when I get the update done.
 
garygid said:
We intend to deliver our work into the public domain, and we
request that our collaborators endorse this same philosophy.
Click to expand...
Sweet! :D [thumbs up]
garygid said:
The Robomo Project breaks down into several sub-projects:

1. Understanding the QC interface, handshake signals, and CAN communication.
2. Construction of a plug that is sufficiently pin-compatible with the LEAF's QC socket.
3. Obtaining or building a suitable, controllable DC power supply.
4. Doing some very careful, well-controlled experiments.
Click to expand...
Sounds like there are several different types of power supplies folks would like to use. Perhaps a key element of the Robomo Project should be:
2.5. Develop a QC controller with parameterized code and a generic power supply interface that can be bolted onto any power supply meeting the minimum requirements.

I think there is a lot of value in having such a component that could be common to everyone exploring this space and it seems to be in keeping with the spirit of the project you set out.
We could
 
KillaWhat said:
The L3 charging on the other hand seems to be controlled by the external charger, with the car reporting some data that the Chademo can use to make adjustments.

I doubt that the 2013 has any significant changes in the DC charging system that would affect it's operation over the 2012 design
Click to expand...

To be clear, the charger is controlled by the car over a CAN link. The charger is dumb the car is smart. ;)

The 2013's are better at estimating time remaining and SOC, and send these bits of info to the quick charger. The blink is only reporting what it gets from the car. For once it's not blink's fault! :lol: I also hope the update addresses this, although I'm not exactly holding my breath.

You can select "100%" by going into other settings (or other selections, cant remember the name at the moment) when presented with the 70 and 80% options.
 
I don't have QC on my LEAF, but I really like the intent of this project. I have nothing to bring to the table of any practical use, except free cPanel/apache/php/mysql web hosting on a VPS if desired. Feel free to PM me and I'll hand over keys to an account. Otherwise, I'm just looking forward to seeing what comes out of this.
 
Ten times per second the car sends, among other things, the
current value that it expects the QC to provide.

When the battery gets fuller, the car starts requesting less current.
When the car requests zero (0) current, the charging session ends normally.
Other than error conditions, it is up to the car to decide upon the charging
profile, and to determine when to end the charging session.
Of course, the user can push the STOP button at any time.

We have posted a CAN-Do compatible log of the QC-CAN bus during
a QC session, which was ended by the car at 80% SOC, as I recall.
In the log, one can follow the commands from the car to the
QC device, and the responses.

The QC device really has no idea how big or how full the car's battery is,
or what type of battery chemistry is involved, or even what type of car it is.

The car does send a "progress" type value to the QC machine,
but it is not yet clear to us just how this number should be scaled, or
what it is supposed to represent. It appears that the QC machine
usually uses this value to display some kind of progress indicator.
 
To get started we bought a battery charger kit that should be
able to charge at about 10 kW. The charger was designed to
charge a dumb battery pack, using a pre-specified constant
current up to a certain voltage, then maintain the constant voltage
as the current decreases, and then (at some point), quit charging.

It is about one cubic foot, and air cooled. However, it will
just be used for testing the interface and protocol, and be
replaced by another design later.

We are are working on substituting a different controller, that
can control the charger differently (as needed for a QC session), and
is able to do the 4 handshakes and the QC-CAN bus communication
with the LEAF.

The first version of this Robomo controller will likely be run from an
isolated power supply that can be grounded to the car's "ground"
(usually the chassis) and be optically isolated from the charger itself.
 
I would like to participate in this project, if I may.
I have Gary's famous meter. I have access to a quick charger at Van Ness Station in D.C.,
and hopefully to more, soon. And I have recordings of at least 5 quick charges I can play
back, from charging my Blue 2012 Nissan LEAF, from the Chademo.
If you get as specific as possible about the D.C. power supply, I can cobble together one
of those. I have chargers for my older EV's which might work, if I do not have to output
extreme amounts of power. I have access to 208 three phase at work, if necessary. And
even 480 three phase could be arranged, perhaps.
I keep getting off topic on my posts, but I've assembled a fleet of raspberry pi's with
attached arduino uno's and would like permission/help to try to port Gary's Can Do from a PC platform
to a Raspbian platform, for portability and cost and networking and power consumption
reasons. And maybe upgradeability to the Udoo platform if/when it becomes available.
A pi might fit inside the DC power supply....
I will try to limit my posts to be only about home brew Chademo, but I think we need one
more thread added if someone has not already, to investigate using the motor controller
as a charger, as reportedly done in the Renault EV. Someone needs to make available the specs on
how that is done and see if it is possible to do the same thing in the Nissan LEAF.
My belief is that the high price of chargers and batteries are the two remaining barriers
to widespread acceptance of EV's. It makes no sense for a "Plug", for example, to cost
$2,000 (140 amp Chademo plug), or even $200 (80 amp J1772). Maybe we need an open
source plug thread... Let me stop here before I get too far off
topic again. I just mean to say that I believe this project is what we need most now, along
with do it yourself battery fabrication 101(another needed thread- Open source battery,
and the accompanying Open source battery management system thread). :lol:
Back to the home brew chademo project, at hand.
Thank you,
Jim
 
JeremyW said:
The car requests the charger do an insulation test by having the charger ramp to 500v while looking for leakage current with the contactor to the battery open. After no leakage current is detected (and the charger goes to 0v), the car closes the contactor and the charger ramps up.
Click to expand...

Who's checking for leakage prior to charge? The charger or the car? Can the charger just say "ok, we did our test" or does the car expect to measure the HV from the charger at the port prior to closing the battery contactors? Maybe I should just look at the spec...
 
GregH said:
Who's checking for leakage prior to charge? The charger or the car? Can the charger just say "ok, we did our test" or does the car expect to measure the HV from the charger at the port prior to closing the battery contactors? Maybe I should just look at the spec...
Click to expand...

The answer is both.

The car is continuously checking for a ground fault, the service manual calls this signal an "IR short pulse" and is some kind of capacitance measurement. If the contactor closes and this value changes beyond a certain threshold, you can brick your car. (need to take to dealer to un-brick).
The car cannot check the HV leakage on the charge cable if the contactor is not closed, the charger checks this with whatever ground fault interruption circuity the designer wants to use, the impedance just needs to match the car as to not trigger a fault.
 
jclemens said:
GregH said:
Who's checking for leakage prior to charge? The charger or the car? Can the charger just say "ok, we did our test" or does the car expect to measure the HV from the charger at the port prior to closing the battery contactors? Maybe I should just look at the spec...
Click to expand...

The answer is both.

The car is continuously checking for a ground fault, the service manual calls this signal an "IR short pulse" and is some kind of capacitance measurement. If the contactor closes and this value changes beyond a certain threshold, you can brick your car. (need to take to dealer to un-brick).
The car cannot check the HV leakage on the charge cable if the contactor is not closed, the charger checks this with whatever ground fault interruption circuity the designer wants to use, the impedance just needs to match the car as to not trigger a fault.
Click to expand...

The car constantly checks for isolation from HV+ to GND and HV- to GND. There is a voltage sense on the DCQC port but as far as I can tell from the manuals it's only use to verify the integrity of the Vehicle's DCQC contactors.

When the charger starts up there is a 500V isolation test done on the charger. If the charger detects a fault it terminates and informs the car.

What's unclear is if the car does anything during the charger's 500V isolation test. From the car's perspective if it never sees the 500V is it going to complain? There's nothing I can find in the spec that says it should..
 
garygid said:
....

Another 3D model was made using Binder (?) and used to
print a 4-section 3D-Printed "plug" which will be sufficient
to hold the pins for our first experiments. No, it does not
yet have the latch and interlock, but that is being worked on.

Printed in PLA plastic, in a nearby country. :D

The handle is in two halves, connecting to a pin-retainer plate,
which attaches to the rear of the plug (pin holder part) that
mates with the QC socket.
Click to expand...

That nearby country would be Canada printed by yours truly. And it is not Binder, though you are close, I used Blender.

Today I finally got my second unit printed. Gary has my beta release, this is v 1.0 (for pin holder and plug tip, the rest of it is still being developed)
http://www.thingiverse.com/thing:121581 Follow the link for more images.


This time I used ABS plastic as it is very durable in high heat (still rigid at 100C vs PLA is a soggy noodle at that temperature)
 
jc,
I did not want to reveal your details until you were ready.
Thanks for the nice picture.

This version, with the latch, seems very nicely done.
A good choice of color, for visibility and safety.
And, the ABS plastic, although somewhat more
difficult to print, would seem to be better for this job.

I picked up 2 of our first 4 good copper power pins yesterday.
A person (who actually knew what he was doing) kindly
produced two sets of pins for us.

We are investigating silver plating, at least for the contact
portion of the pins. Any comments or suggestions in
this regard, for your needs, concerning the silver plating?

As soon as we get the silver-plating issue resolved,
we will send two of the power pins to you.

I believe that you made your set of signal pins out of 1/8" rod,
but I used a 3/16" diameter "body".

Getting the power supply current to ramp up quickly enough
to satisfy the car, without blowing something (outside the car),
is a present issue.

Cheers, and Thanks for the splendid help.

I am building a 3D Printer, but have had a lot of delays.
 
Yes Gary, thank you.

I want to add that I will provide the printed plastic parts to anyone else who has proven to have the significant investment in the electronics for developing an open source chademo charger. (the pins and other metal parts are a different story however).
The 3d printed parts are meant to enable experimentation and development, not commercial production. (though you could send the files to shapeways if you want)

I envision a charger that is portable, isolated and can do 17-20kw. A canbus controlled elcon/chinnic/tcch 8kw charger would probably do quite nicely, especially 2 of them for 16kw, this way you could have the option of running off 2 separate 240V 50a connections (like at an RV park). Or run the chargers in parallel from a 240V source on 90 amp breaker.

Thats where we need community collaboration, I have strengths in electronic hardware, and mechanical, however software programming is not really my thing.

edit: I am retracting my offer for free parts. I have planted a couple seeds now and it is time to watch them grow.
 
Our experiments are progressing well, with the handshaking
and CAN communication with the LEAF's QC port doing well.

We have managed to put 10 amps into the port, with the car's
cooperation. In a recent session, while headed higher,
our reading of our "charger's" heat sink temperature got
a too-high indication from the A-to-D circuitry, and the
charging session shut down gracefully, without complaints
from the car.

We are purposely avoiding contact with any Chademo
documentation that is not freely available in the public domain.
So, please do not offer any such material.

However, we could use an expert in power supply design.
1. We need high efficiency to keep the cooling requirements down.
2. We want a properly isolated output, without a big, heavy input
transformer, which probably means a high power switching design.
3. One initial design point is to utilize 50 amps (or less), 240v normal
household or RV Park split phase power. A second step will
allow use of up to 100 amps, to allow about 22 kW charging, or
about 50 amps into the battery pack.
4. Relatively small, and portable, for use at home or on a trip
is also a design goal.
5. A DIY cost of under a few or several thousand dollars is desired.

No, at this point there are no plans to make a UL listed product.

Our first efforts are all toward understanding a safe and effective
process, initially for the LEAF.

Offers of experience or expert advice, please PM me. :D
 
I love this project guys!! great job and awesome work on the 3d printer stuff. I've been looking into a uPrint lately but the wife is kinda like :evil:

Anyways, one area that I might be able to help in is the DC power supply area. I love my LiPo's and DC chargers! And I mod server power supplies for alot of my flying buddies so we can charge 1-5kw units fast at the field. Fully isolated, etc.

My only thing is this, we need 400+ volts.. that's 30 units ganged together.. :lol: YIPES.. but that's 16kw of solid clean enterprise class power.. 2nd to none..

Let me see if I can find some 24v units, that'll knock me down to 15 ganged up.. and that's doable!

The most I've done is 6 in parallel but that's like a 5kw unit of Dell power supplies.. now we're talking in series!!

Fun stuff!
 

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