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Re: Electrify America Network

Posted: Sun Oct 13, 2019 6:01 pm
by coulomb
GRA wrote:
Sun Oct 13, 2019 4:54 pm
Alternatively, EA should charge by the actual rate being drawn at a given time, rather than by the max. rate the car could draw at any time, i.e. a Niro would start the charge paying the 76-125kW rate, then once the charge rate dropped off to <=75kW you'd pay that rate.
What a concept! Fair, and within the capabilities of today's embedded computers!

What I'm trying to say is, this is so obvious and should be so simple to implement.

Re: Electrify America Network

Posted: Mon Oct 14, 2019 6:09 am
by SageBrush
coulomb wrote:
Sun Oct 13, 2019 6:01 pm
GRA wrote:
Sun Oct 13, 2019 4:54 pm
Alternatively, EA should charge by the actual rate being drawn at a given time, rather than by the max. rate the car could draw at any time, i.e. a Niro would start the charge paying the 76-125kW rate, then once the charge rate dropped off to <=75kW you'd pay that rate.
What a concept! Fair, and within the capabilities of today's embedded computers!

What I'm trying to say is, this is so obvious and should be so simple to implement.
.
It does not cover demand charges.

Re: Electrify America Network

Posted: Mon Oct 14, 2019 6:13 am
by DaveinOlyWA
paulgipe wrote:
Sat Oct 12, 2019 5:56 pm
DaveinOlyWA wrote:
Fri Oct 11, 2019 6:18 am
paulgipe wrote:
Fri Oct 11, 2019 5:55 am


Dave,

Would you be willing to comment (on the record) about EA's disparity between CHAdeMO and CCS connections? If I am motivated I might contact CARB about this for the California Settlement. I have a piece I plan to post shortly on this. I didn't get it posted before I left on vacation. ;)

I can contact you off line if you prefer.

Paul
Sure I will comment. How do you want to do this?
I can send you my draft text focusing on EA and California. The focus is on CARB because they might be approachable. I thought I had an email for you but apparently not--or I can't find it. The gist is as described above: EA is favoring CCS and that's what VW uses.

Paul
pgipe@igc.org
That's fine. PM sent

Re: Electrify America Network

Posted: Mon Oct 14, 2019 6:15 am
by SageBrush
GRA wrote:
Sun Oct 13, 2019 4:54 pm

To prevent VW from further gaming this by changing the charging rate break points, ISTM best to allow the max. rate to be selected either on the car, or ideally on the charger. Alternatively, EA should charge by the actual rate being drawn at a given time, rather than by the max. rate the car could draw at any time, i.e. a Niro would start the charge paying the 76-125kW rate, then once the charge rate dropped off to <=75kW you'd pay that rate.
.
I am still uncertain that the tier rate is chosen by the theoretical max charging rate of a car and not the maximum obtained during a session. If the latter, then people can just start a new session when the power drops below a break-point.

----
So much hot air, for a few hundred Hyundai/Kia affected.

Re: Electrify America Network

Posted: Mon Oct 14, 2019 6:18 am
by DaveinOlyWA
SageBrush wrote:
Mon Oct 14, 2019 6:15 am
GRA wrote:
Sun Oct 13, 2019 4:54 pm

To prevent VW from further gaming this by changing the charging rate break points, ISTM best to allow the max. rate to be selected either on the car, or ideally on the charger. Alternatively, EA should charge by the actual rate being drawn at a given time, rather than by the max. rate the car could draw at any time, i.e. a Niro would start the charge paying the 76-125kW rate, then once the charge rate dropped off to <=75kW you'd pay that rate.
.
I am still uncertain that the tier rate is chosen by the theoretical max charging rate of a car and not the maximum obtained during a session. If the latter, then people can just start a new session when the power drops below a break-point.
Rate is determined before car starts charging

Re: Electrify America Network

Posted: Mon Oct 14, 2019 6:24 am
by SageBrush
DaveinOlyWA wrote:
Mon Oct 14, 2019 6:18 am
SageBrush wrote:
Mon Oct 14, 2019 6:15 am

I am still uncertain that the tier rate is chosen by the theoretical max charging rate of a car and not the maximum obtained during a session. If the latter, then people can just start a new session when the power drops below a break-point.
Rate is determined before car starts charging
.
Remind me again why you think that is so ?
I remember we have discussed this but I have forgotten the details

I wonder if the handshake has the car passing on its maximum Amps and then the charger multiplies by some set maximum voltage constant to arrive at a max kW rating used for tier setting. It would explain the rate behavior some think they are seeing.

I think if fair however to point out that to the extent that EA is trying to recoup demand charges it will be figured by the meter, not the power to the car. That is a 10 - 15% difference due to conversion losses, and perhaps more if cooling is also figured.

---
Addendum: http://tesla.o.auroraobjects.eu/Design_ ... V3_1_1.pdf
Page #7 is informative. The handshake passes max current and voltage early on, and later in the handshake passes voltage request to begin the charging session. So even if we agree that the tier is set before current starts flowing, I think EA has a choice to either use the max voltage of the battery spec OR the initial voltage request.

Re: Electrify America Network

Posted: Mon Oct 14, 2019 2:08 pm
by paulgipe
Guy,

Let me ponder that. It's too much for this piece, but possible in another piece.

We were traveling for almost a month and we come back and nothing has happened on the stations that I am following. They are still not active and EV Connect still hasn't started construction on theirs.

Paul

Re: Electrify America Network

Posted: Tue Oct 15, 2019 6:11 am
by DaveinOlyWA
SageBrush wrote:
Mon Oct 14, 2019 6:24 am
DaveinOlyWA wrote:
Mon Oct 14, 2019 6:18 am
SageBrush wrote:
Mon Oct 14, 2019 6:15 am

I am still uncertain that the tier rate is chosen by the theoretical max charging rate of a car and not the maximum obtained during a session. If the latter, then people can just start a new session when the power drops below a break-point.
Rate is determined before car starts charging
.
Remind me again why you think that is so ?
I remember we have discussed this but I have forgotten the details

I wonder if the handshake has the car passing on its maximum Amps and then the charger multiplies by some set maximum voltage constant to arrive at a max kW rating used for tier setting. It would explain the rate behavior some think they are seeing.

I think if fair however to point out that to the extent that EA is trying to recoup demand charges it will be figured by the meter, not the power to the car. That is a 10 - 15% difference due to conversion losses, and perhaps more if cooling is also figured.

---
Addendum: http://tesla.o.auroraobjects.eu/Design_ ... V3_1_1.pdf
Page #7 is informative. The handshake passes max current and voltage early on, and later in the handshake passes voltage request to begin the charging session. So even if we agree that the tier is set before current starts flowing, I think EA has a choice to either use the max voltage of the battery spec OR the initial voltage request.
There was a Niro that never exceeded 55 KW on a charge and was billed 2nd tier rates. We also had one locally that never exceeded 40 KW (started charge at 80%) and was billed 2nd tier rates.

So it would seem the handshake only determines the car and not current condition of battery.

Re: Electrify America Network

Posted: Tue Oct 15, 2019 6:53 am
by SageBrush
DaveinOlyWA wrote:
Tue Oct 15, 2019 6:11 am
So it would seem the handshake only determines the car and not current condition of battery.
No. Read the link I posted
The handshake also includes the initial voltage request

Re: Electrify America Network

Posted: Tue Oct 15, 2019 6:22 pm
by GRA
As Dave noted, there have been several reports, not just the ones he noted, of Niros and maybe Konas too (I forget) being billed at the 125kW rate throughout their charge. Owners have been complaining to EA. The rationale that you need to cover demand charges is gone if the car or the charger allows you to select a lower max. charge rate. Anyone who does so knows that they're going to be at the charger long enough for it not to be an issue.

I did suggest to Kia that, as EA has zero incentive to do this themselves absent being forced to by governments, they should reduce the car's max. charge rate to 75kW. The problem with that approach is that EA could then simply change the max. for the lowest tier to 73 or 70 kW or what have you, much as Nissan can change the definition of a 'bar' whenever they wish, which is why I suggested the probably more expensive but more flexible approach of allowing the customer to set a variable max. charge rate on the car.

Increasing the max. charge rate is another approach, but you'd want to go to 1.5C or more, which is presumably not good for the battery, and unless the rate stays high for a long time you'd be getting little benefit. VW says their MEB cars will have max. rates of 125kW, which seems problematic given the biggest battery pack sizes they've announced (77 kWh usable out of 82 kWh total), but if they want to warranty the packs and the average charge rate is high throughout, great.