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[Rugby4life]

Given the currently available equipment/technology, are there any insurmountable issues to prevent developing a SAE Combo charging system for a Zero? I've read bits and pieces in various threads about why it can't be done currently but I haven't seen the information laid out in a format of "This is what can be done to make it happen." For traveling serious miles in a day, a condition I've been suffering with for 3+ decades, a combo setup would be the most convenient. I could use DC when available and standard J plug the rest of the time.
While we're at it, was the lack of compatible Chademo chargers on the west coast the only reason Zero discontinued the option which would greatly benefit east coast riders? We have many compatible chargers especially at almost every Nissan dealership (of which I have 3 within 17 miles).
As I said, I'd like to hear "This is how we can make it happen" instead of "We can't because". Looking forward to learning something new.

[togo]

SAE Combo AC charging is just J1772.

SAC Combo DC charging is runs "homeplug"
ethernet-over-powerline signalling to identify
voltage required.

https://en.wikipedia.org/wiki/SAE_J1772
"support charging at 200–450 V DC"

So DC voltage is too high, but if you are
carrying chargers to charge off AC input,
the same chargers should be able to charge
with DC input (modern switch-mode power
supplies rectify first, and a rectifier fed DC
is usually just rectifier with very bored diodes.)

So, yeah, "just" the signalling to be reverse-
engineered, and an ethernet-capable controller
to be embedded do the signalling. 

(BTW, I have found a scientific paper with
plans for a 30kw bidirectional DC-DC converter
that's 98% efficient from 10-90% load that I'm
trying to build- if it works out, it may be applicable
to this project as well as storing solar, etc.)

Re Chademo- the testing was reportedly done on
stations in a network that did not do the lower voltage
the FET-based Zero systems require, but that network
did not expand, and the compliant networks did, so
there's no reason to believe the Chademo devices,
tested today, would not have more success.  But no,
I don't think there was a conspiracy against east coast
Zero owners.  I think that until Zero starts making a
profit for their investors they have to be very careful
how they spend their limited R&D budget, and that
making better motorcycles with better components and
longer range is, IMHO, doing the right thing.

[hubert]

Are you sure any charger can be DC-supplied? I have confirmed it with very small "USB" chargers, but with bigger ones it may not be possible, because of the PFC circuit which expects an AC signal input to synchronise the boost converter with a sine-wave-like input current or voltge waveform.

[togo]

No, I am *not* sure *any* AC charger can be DC supplied.

*Only* the ones that start with a rectifier stage.

That is to say modern switch-mode power supplies.

Please, don't overstate me.

You may have a point about PFC, I may not understand
that part sufficiently.

[Rugby4life]

Togo, I believe you misunderstood my question about the Chademo option. I wasn't inferring a conspiracy against east coast riders. I was questioning if there was some other reason to withdraw it as an option for those unaffected by the out of spec chargers. The R&D has already been done so there's no major investment needed to offer it again (with the proviso that it may not work with certain units).

Concerning the DC-DC converter, how would it be fed Chademo or SAE Combo? As I said, I'm trying to understand the hurdles and facilitate a conversation on the present or near future possibilities. As I read your response, the major problem with SAE is the 200v minimum charge rate. So other than charging 2 bikes concurrently from the same plug, is there another work around? Keep the info coming, I'm slowly learning.

[togo]

As I understand it they had developed a product, found it didn't work on
enough of the stations tested that it would be frustrating and expensive
to sell and support.  At the time.  For the sample of stations available at
the time.

But I don't really know the whole story, that's just what I pieced together.

Yes, I know, not a conspiracy, but you know, you set it up with an East Coast
West Coast kind of comment.

Workaround to the 200v minimum would be, if you have a AC charger that
also works on DC, to run it through that.

In other words, tell the station that you require within the range they can do that
overlaps what the charger can handle, say, 240VDC and use that to run the charger
at a rate limited to what it can do and what your battery can handle.

For example, I'd expect that my diginow SCv2 9.9kw system would (if compatible
with DC, which I have yet to test), be able to take 240VDC to charge my battery at
1C, i.e. 9.9kw, up to 116.5VDC.

So if that's true, then the missing piece is the signalling to tell the station that a vehicle
is present, and that the vehicle is ready to charge at 240VDC.

And the inlet itself.

[togo]

The signalling for Combo CCS is ethernet over powerline, homeplug style.

The signalling for Chademo and Tesla is Canbus.

People having working Chademo or Tesla could help by recording the signalling during live charging sessions, maybe this stuff can be reverse engineered.

[togo]

I just got word that the SCv2 bricks have been tested on DC input, and they run at full power from ~170-360VDC

(And that at < 170VDC they run at reduced power, which is like wall plug / rescue cable mode.)

[Rugby4life]

Togo, does that make a SCv2 and Chademo plug a viable option? Also, can the SCv2 be wired to accept both a J-plug AC and a Chademo DC input? not both at the same time, of course, but it would let you use either input based on what's available at that station. Just asking because my understanding of the topic is the figurative equivalent of drawing wiring schematics with crayons.

[Keith]

And another crazy idea for those of us with modular FX packs is charge two packs in series, right up to 232VDC. Possible?

[BrianTRice@gmail.com]

Meta note: Please title the thread with the actual topic at-hand. "Insurmountable issues" is broad and doesn't indicate whether I should read or archive a thread for the wiki. The topic is SAE Combo charging.

[Rugby4life]

Meta apologies Brian. I didn't know there was a titling protocol. Actually, the object of this thread is not as narrow as just SAE Combo charging. I'm hoping to develop an understanding of where we are with DC charging currently and what issues need to be overcome to make it an accessible feature. I started my questions with the combo set up because it builds off the level 2 J-plug that seems to be the most popular. I also asked about Chademo even though it would require a separate J-plug port for level 2 charging. How about a title of "DC Charging Options"? Is changing the title as simple as editing the first post?
Togo's replies are exactly what I am hoping for to answer 3 questions.
1. Where are we now?
2. What are the hurdles to implementation?
3. Here's how we overcome each hurdle. (not technically a question but you know what I mean)

[Shadow]

I didn't know there was a titling protocol. Actually, the object of this thread is not as narrow as just SAE Combo charging. I'm hoping to develop an understanding of where we are with DC charging currently and what issues need to be overcome to make it an accessible feature. .... How about a title of "DC Charging Options"? Is changing the title as simple as editing the first post?

Done.

Use "Report post to moderator" link and explain what you would like the thread titles changed to. Each post can have its own different title within the same topic. Moderator can help change all titles within the topic. Thanks for contributing!

[Keith]

Now that we know what we're talking about, does the DC charging EVSE control the current as well as voltage? Or does it just select and provide a more or less constant DC voltage and leave it up to the vehicle to regulate charging current? As in when to switch  from CC to CV etc.

[Doug S]

I scanned through the CHAdeMO spec briefly a while ago, and IIRC it allows you to specify both voltage and current. So if I understand it correctly, and if the charging stations met the spec (which we know they don't all), we could rig up an interface that told the charger "116V @ 100A" and it would give us 100 amps until we hit 116V, then hold at that voltage while the current ramps down. In other words, a nice clean CC/CV charge that would charge at maximum speed all the way up to 100%.

If only. But it does seem possible to instruct the CHAdeMO station we need, say, 250V @100A, and run one of the high-speed chargers off of that DC voltage, presuming the charger has a rectifier bridge front end, as togo points out. It seems really silly to carry a high-power charger around to make up for the deficiencies of the DC charging equipment that's out there, but it would seem to be possible. If there's nothing around but a CHAdeMO station, you could use it.

I'd imagine that's how CCS handles DC charging too -- it seems like a no-brainer. So assuming a bridge front end, you could do the same thing.