DC Quickcharging for Leafs at dealers

[P71VIC]

Give in Elon and Nissan (Carlos Chosn?) and you can star in "Who Saved the Electric Car". I'm a Marylander and can't even drive my Leaf to Ocean City in the summertime. Well, unless I want to spend 4 hours at a lonely professional park in Stevensville, for crying out loud. I guess I could bring a hibachi and have a very long picnic? Making a 3 hour drive take 7 hours is not progress. Regardless of the outcome, America needs a Level III infrastructure for the BEV to survive.

amen! A quick charger in Easton and or Cambridge would cover the "down da ocean" requirement for the whole Washington/Baltimore area.

I hear the first Chagdemo might be installed now in Bethesda?

[DaveEV]

I am not sure whether any of these dual-hose units have been deployed. They have their hands full installing more single-hose units, up to 6 at one location, to keep up with demand.

Most of the supercharger locations are already deployed are dual-host units just as you described. A couple are single host units and a few more are only ~30 kW capable units (Gilroy SuperChargers for example appears to have a dual-hose unit and two ~30 kW superchargers - 4 plugs total).

...it's not unreasonable to think that DCQC stations couldn't offer multiple plugs at a single site (possibly even from a single piece of hardware). You wouldn't need multiple underground tanks, they all share the same source!

The problem is exactly that they share the same source. That source can only provide a certain amount of electricity. On top of that, each plug requires its own quick charger, which are neither cheap nor reliable at this point. I think Tesla is smart to provide the high-speed chargers in the car.

True, but this would be the case if it were two Chademos or a Chademo and a Frankenplug.. Just last week I tried "sharing" a dual port Blink station with another Leaf and when the 2nd car plugged in it had to wait until my "80%" (ie 72%) charge had completed.. no sharing of electrons, strictly single file. There's no reason the DCQC charger guts couldn't feed two different connection protocols albeit one at a time.

Well, it's probably not quite that simple - depending on the architecture of the system. The Tesla got the design right and their SuperCharger can handle this because it has a stack of 12 10 kW AC/DC converters and is able to allocate them to two different plugs. I'm bet that the Blink design uses a single 50 kW AC/DC converter, so splitting the DC output to two different cars would mean that you would need an additional DC/DC converter for each car/plug.

It's too bad that they went through the trouble of engineering it that way - but given that it'd be more complex and the already very low reliability of the units (how often are even new units Blinked from the get go???).

Personally, I would prefer 2 25kW stations over a single 50 kW station. I'd even bet that the cost of 2 Nissan or Fuji's 25 kW CHAdeMO stations are less than the cost of one single Blink CHAdeMO. Having 2 separate stations means that you're much more likely to have one that is operational given the general reliability of QC stations.

[DaveinOlyWA]

I used two different Blink DCFCs yesterday and both stated 60 KW power available. Blink could allow the 2nd car to start charging as soon as the charging rate started to taper on the first car but does not. Is there so technical reason for this?

As it stands now, we are getting lines mostly from people wanting greater than 80% which takes much longer. I see no reason why the 2nd car cant start since the first car's rate will be a very small fraction of the station's capability.

[tbleakne]

I used two different Blink DCFCs yesterday and both stated 60 KW power available. Blink could allow the 2nd car to start charging as soon as the charging rate started to taper on the first car but does not. Is there so technical reason for this?

As it stands now, we are getting lines mostly from people wanting greater than 80% which takes much longer. I see no reason why the 2nd car cant start since the first car's rate will be a very small fraction of the station's capability.

If the Blink is not modular, so that one big charger supplies all 60 kW, then it cannot be split, because each car is in a different part of its charge cycle and hence needs a slightly different voltage.

The Tesla design uses triples of 3 x 10 kW charge modules, one module per phase. Each module can adjust its voltage to match the demand of the car to which it is connected. Each module has to be assigned to a single car.

[Levenkay]

I used two different Blink DCFCs yesterday and both stated 60 KW power available. Blink could allow the 2nd car to start charging as soon as the charging rate started to taper on the first car but does not. Is there so technical reason for this?

As it stands now, we are getting lines mostly from people wanting greater than 80% which takes much longer. I see no reason why the 2nd car cant start since the first car's rate will be a very small fraction of the station's capability.

Please note that this behavior on the part of Blink users is at least heavily influenced (if not solely caused) by Blink's "flat $5 fee" pricing policy.

[DaveinOlyWA]

I used two different Blink DCFCs yesterday and both stated 60 KW power available. Blink could allow the 2nd car to start charging as soon as the charging rate started to taper on the first car but does not. Is there so technical reason for this?

As it stands now, we are getting lines mostly from people wanting greater than 80% which takes much longer. I see no reason why the 2nd car cant start since the first car's rate will be a very small fraction of the station's capability.

If the Blink is not modular, so that one big charger supplies all 60 kW, then it cannot be split, because each car is in a different part of its charge cycle and hence needs a slightly different voltage.

The Tesla design uses triples of 3 x 10 kW charge modules, one module per phase. Each module can adjust its voltage to match the demand of the car to which it is connected. Each module has to be assigned to a single car.

**disclaimer; not an engineer**

i think voltage input is static and only current varies depending on the perceived SOC of the vehicle.

guessing Ecotality simply put in one unit which is why only one car can charge at a time. trying to save money i guess...

[planet4ever]

**disclaimer; not an engineer**

i think voltage input is static and only current varies depending on the perceived SOC of the vehicle.

I'm not an engineer either, Dave, but that can't be right. I've read many times here that the battery is charged in two phases, first gradually increasing the voltage so that the current is constant, then holding a constant voltage for the top off and letting the current drop. Since E=IR, this isn't really based on the "perceived SOC", but on the resistance of the battery at any point of time. My (perhaps simplistic) view is that the external charger doesn't try to control the current. It just provides the voltage that the LBC asks for, and the LBC specifies a voltage that will result in the current it would like to see.

Ray

[DaveinOlyWA]

**disclaimer; not an engineer**

i think voltage input is static and only current varies depending on the perceived SOC of the vehicle.

I'm not an engineer either, Dave, but that can't be right. I've read many times here that the battery is charged in two phases, first gradually increasing the voltage so that the current is constant, then holding a constant voltage for the top off and letting the current drop. Since E=IR, this isn't really based on the "perceived SOC", but on the resistance of the battery at any point of time. My (perhaps simplistic) view is that the external charger doesn't try to control the current. It just provides the voltage that the LBC asks for, and the LBC specifies a voltage that will result in the current it would like to see.

Ray

oh ok. not sure what you are saying is different from what i said. i think my explanation was just off a bit? if you apply a higher voltage to a discharged battery, the voltage will drop due to resistance of battery and slowly rise as the battery charges. as the voltage hits a certain point, it triggers a reduction in current. i dont remember seeing voltage change dramatically mostly because most chargers simply dont show it but i do see current dropping?

[KillaWhat]

I apologize if someone already said this, but if the dealers had DCQC's, I would go to Nissan Dealers.
Except for this Leaf, I would never have been caught dead in a Nissan dealer.
Just not on my car buying radar.

Nissan Dealers would get me walking around the showroom for 15 minutes periodically, and isn't that 3/4 of the battle?

I personally sold every Leaf my dealer had by talking to other people.
I saw a pretty cool convertible crossover at the dealer when I was there last, and while I don't want it personally, I told other people about it.

I wonder what that dealer spends on advertising to get people into that showroom?
I bet more than a $10K DCQC every month.

Hell, we only have ONE DCQC any where near me, and I drive to it just for giggles.
It got me into a Denny's, so anything is possible.

[TomT]

I see a need in the future for an internal setting in the QC that limits a charge to 80% for just this reason. That last 15% takes an eternity, ties up the charger, and is hard on the battery...

As it stands now, we are getting lines mostly from people wanting greater than 80% which takes much longer.