Level III charging a Leaf

[DaveEV]

If you read the display carefully and multiply, you can determine the charge rate which is voltage x current.

I saw 392V and 70A early on which is 27.4 kW.

By the end of the charge voltage was barely higher at 393V but at 30A or about 12 kW. Still 4x faster than a regular L2 charge.

 

[AndyH]

Here's what the service manual states:
...
When charging is not completed and the charge time set on the quick charger or the time out (approximately 60 minutes) set on the vehicle elapses, charging stops.

NOTE: If charging stops before charging is complete, additional charging by quick charge can be performed again.

It's interesting to see the combination of time-outs here. The car has a 60 minute limit, the charger is supposed to have a 20 minute on, 10 minute off cycle. Both say the charge can be restarted.

I'd like to see what happens if we set an 80% charge from nearly empty, then QC to the charger's 20 minute limit.

 

[garygid]

Is a QC charging station REQUIRED to have a limited (20 on 10 off) duty cycle, or just PERMITTED to be less than a full 100% duty cycle?

 

[PDXLeafer]

Actually, the QC seemed to have a 60 minute limit on it.

 

[AndyH]

Is a QC charging station REQUIRED to have a limited (20 on 10 off) duty cycle, or just PERMITTED to be less than a full 100% duty cycle?

The SAE J1772 task force has reps from TEPCO, other manufacturers using the TEPCO/CHAdeMO quick charge standard, and Nissan as part of the active group. The 20 minute on/10 minute off was referenced as a 'hard' limit in the TEPCO units that would be duplicated in the J1772 DC protocol. Remember that the vast majority of the J1772 process is about interoperability and global harmonization.

It's very possible that the Leaf will take a charge at L3/DCQC rates to 80% and then back-down to something closer to L2 'fast'. There's nothing stopping the L3 equipment (or the Leaf) from charging to 100% at an L1 rate if either device saw a need to do that.

Gotta love trying to nail Jello to a tree.

edit...type...10 not 20 minutes off...

 

[garygid]

I doubt that anybody would want to pay good money for a fuel "pump" that would be available for use only 67% of the time. It would frustrate car owners and charging-station owners.

There is no technical necessity that requires building such a "handicapped" piece of equipment.

The political reason might be that it would charge most "range-extended" EVs (smaller battery hybrids) in 20 minutes or less, but be frustratingly unsatisfactory for BEVs (with larger battery packs), that might need 30 or 40 or 45 charging minutes to "finish" charging.

 

[AndyH]

I doubt that anybody would want to pay good money for a fuel "pump" that would be available for use only 50% of the time. It would frustrate car owners and charging-station owners.

:shock: :roll: Set's see...20 plus 10 is 30, so that would be a worst case of 66.67% 'on' and 33.33% 'off' - except that one can simply press the 'start' button to reset the clock, so the 1/3 'off' isn't mandatory.

The political reason might be that it would charge most "range-extended" EVs (smaller battery hybrids) in 20 minutes or less, but be frustratingly unsatisfactory for BEVs (with larger battery packs), that might need 30 or 40 or 42 minutes to charge.

You might have found the secret! The Illuminati forced TEPCO to to include the handicap so that L3 wouldn't be adopted by those "hybrid" guys like GM and Toyota. Heck, it even scared Ford away - no L3 on the Focus. Great find - that must mean the New World Order bosses really like "real" EVs! :lol:

(holding head in hands looking for motrin...)

 

[garygid]

I thought that the "20 on, 10 off" was introduced as part of the suggested US "standard", and was NOT part of TEPCO at all.

Perhaps my mistake, sorry.

 

[AndyH]

I thought that the "20 on, 20 off" was introduced as part of the suggested US "standard", and was NOT part of TEPCO at all.

Perhaps my mistake, sorry.

Thanks Gary - fixed the typo. It was correctly stated as 20/10 at the linked message thread but I fat-fingered the number here. edit... Gary - it was also correctly listed in a number of posts immediately above as 20/10. ...edit

Yes - the duty cycle info was from an SAE J1772 meeting - but if I got the correct nudge from my notes, it was specifically about a timer in the TEPCO/CHAdeMO charger.

I recall finding something in the Leaf service manual (while searching for something else) that talked about charge timer messages for QC, but haven't yet re-stumbled on it...and I don't remember was I was searching for last time.

Did find this in the Vehicle Charging section of the service manual though - page VC-97:

Notice the fourth "Check Items" down: "Charging is Stopped by the Quick Charge Timer". It looks like there are competing timers that can come into play when quick charging.

So no - I'm not ready for a padded room and 'huggy coat' quite yet.

 

[evnow]

I hope we get a QC here in Seattle soon - and I can lease the car. Then, I can do all the QC experiments we want

 

[Coffee_Slurry]

Seriously -- I wonder what they'll think of us hanging out at the first L3 chargers with o'scope, CANBus analyzers.. connecting and disconnecting..

 

[garygid]

AndyH, Thanks, my friend!

1. This is the first I have seen of charging to 90%, and with QC. Often, when using QC, one would be starting below 50% SOC, and stopping at 90% instead of 80% makes the QC more useful.

2. Presumably, assuming the battery temperatures are not too high, one could immediately re-start the QC and charge to 100% (in an unknown amount of time)?

3. Often, when using QC, it would be after driving a fair dstance, so in colder weather the battery might be heated up sufficiently by use to allow a QC and continued driving.

 

[smkettner]

AndyH, Thanks, my friend!

1. This is the first I have seen of charging to 90%, and with QC. Often, when using QC, one would be starting below 50% SOC, and stopping at 90% instead of 80% makes the QC more useful.

2. Presumably, assuming the battery temperatures are not too high, one could immediately re-start the QC and charge to 100% (in an unknown amount of time)?

3. Often, when using QC, it would be after driving a fair dstance, so in colder weather the battery might be heated up sufficiently by use to allow a QC and continued driving.

Would L2 be just about as fast at that last 10%? I would be curious what the charge rate is for the QC as it approches 90%.

 

[garygid]

Perhaps even slower yet as it approaches 100%.
It will be helpful to see some real data for the 70% through 100% QC.

 

[PDXLeafer]

Might get a chance this weekend, but based on what I saw so far, yes. It is a fairly linear reduction in Amps as capacity is reduced. The big ole 'X' graph

 

[garygid]

For now we are assuming that the tapering-off current is happening because the LEAF is asking for that "profile".

However, it is possible that the QC station would reduce its own current output (below what the EV asked for) if the QC unit's internal circuitry is getting too hot.

Also, there might be a minimum current that it can supply. Ask for less and it just shuts off?

 

[AndyH]

Glad to help, Gary.

This info hit me hard. I got stuck in the "L3/80%/30 minutes" loop and didn't think beyond 80% or 20-30 minutes. It's great to see that L3 to 100% is part of the plan!

With no other control inputs, current will taper as part of the normal two-stage lithium charge process - constant current then constant voltage. But we can probably expect the possibility of a more 'stair-step' current drop if we need to slow the charge for any reason.

The Leaf's charger appears to be the brains of the the L3/QC charge process, and the charger gets info from all the cars's systems. I think we can very safely expect that the car will be in complete control of the charge.

My gut says worst case quick charge would be an extremely hot day in Arizona, after a high-speed 80 mile drive, and an immediate L3/QC to 100%. I would expect the car's systems to handle that effortlessly.

 

[DarkStar]

The Leaf's charger appears to be the brains of the the L3/QC charge process, and the charger gets info from all the cars's systems. I think we can very safely expect that the car will be in complete control of the charge.

My gut says worst case quick charge would be an extremely hot day in Arizona, after a high-speed 80 mile drive, and an immediate L3/QC to 100%. I would expect the car's systems to handle that effortlessly.

Correct, I would expect it to as well.

 

[smkettner]

Perhaps even slower yet as it approaches 100%.
It will be helpful to see some real data for the 70% through 100% QC.

If L2 is just as fast for the top off you may as well switch power cords and let the next in line use the L3

 

[linkim]

Does anyone know if the battery is air cooled with the fan during QC? I can imagine that after a long drive in AZ or other hot regions, the battery pack will be quite warm. In this situation, is there a temperature at which the battery cannot be QCed? My 2002 Prius battery cannot be charged (regen or ICE) if it gets too hot.