L3 Charging curve

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LindsayNB

Active member
Joined
Dec 10, 2010
Messages
41
I recently read an article that mentioned that a L3 charge would reach 60% in five minutes. I've read 28 minutes for 80% in several places. 60% in five minutes can't possibly be right can it?
 
LindsayNB said:
I recently read an article that mentioned that a L3 charge would reach 60% in five minutes. I've read 28 minutes for 80% in several places. 60% in five minutes can't possibly be right can it?

The L3 Charger can provide 50 KW at one time - the in home (L2) currently only does 3.3 KW, appart from that is the Voltage that plays a roll as well. L3 comes in at 480+ volts DC - (no need for conversion to AC), the L2 only comes in with AC 240V needs to be converted to DC - the conversion by it self is a slow down.

So you are pumbing about 15X the power into the battery - so yes the 60+% SOC is not unrealistig in 5-10 minutes - depending on the current SOC of the battery of course too.

hope that helps
 
Sounds like you're asking about "DC Quick Charging" since there is no such thing as Level 3 (L3) charging yet...

From what I've been told, here is a typical DC Quick Charge profile:

DCQuickChargeProfile.jpg


This is a Nissan LEAF with over a 50% SOC. It starts out at 48 KWh and 5 minutes later starts decreasing.

Hopefully once I get my LEAF, I'll be able to get a charging profile graph from our DC Quick Charge station here in Portland and we'll find out how quick it goes for sure. My understanding is that from 0% SOC it's fairly linear to 80% SOC and that takes just about 26 minutes. This jives given a rate of 48 KWh. The last 20% is what you see decreasing there on the graph, taking about 20 minutes. So in theory, the first 80% is charge at a rate of 2.46 miles per minute of charge, then it decreases to about an average of 1.25 miles per charge per minute.
 
A few weeks ago I had the opportunity to play with the official Nissan service tool (Consult III+) and one of the parameters the battery ECU supplies is a Max discharge and charge permitted. At the time the car was at around 50% SOC and the pack reported 55 degrees F internal temp with 110kW max discharge limit and 30.34kW max charge limit. This means that the fastest you could charge this particular Leaf (at that time) would be 30.34kW! Maybe this number increases once the pack is warmer, but I would be skeptical of 50kW!

Incidentally, that could recharge the pack from 0 to 100% in under an hour which is pretty fast considering the Leaf pack has no active thermal handling!

-Phil
 
Is it correct that the LEAF, when doing QC chaging:
1. stops at 80% if the QC charging started below 50%?
2. charges to 100% if the QC started over 50% SOC?

So, if starting a QC at 20%, a manual intervention (usually after the 80% is reached an the QC stops) is required to charge to 100%.
(eirher a manual Strat-Immediate button press in the LEAF, or perhaps a "Remote" Start-Charge command sent to the leaf)
 
LindsayNB said:
I recently read an article that mentioned that a L3 charge would reach 60% in five minutes. I've read 28 minutes for 80% in several places. 60% in five minutes can't possibly be right can it?
I don't understand why everyone is dancing around the question. This is simple math after we get past a couple of assumptions. here are my assumptions:

Usable pack capacity = 24 kWh
Low battery condition is raised at 15% capacity

Note that all Nissan charge time estimates (L1, L2, L3) are based not on a completely discharged battery, but on charging from the point where the low battery charge warning light comes on. See page CH-6 in the owner's manual.

With my assumptions, charge to 60% really means (.6 - .15)*24 kWh = 10.8 kWh. Even if charging were 100% efficient (which it can't be), to get 10.8 kWh into the battery in 5 minutes (1/12 hour) you need to apply 10.8*12 = 129.6 kW.

Given a 50 kW maximum charging rate, there are no reasonable assumptions which could get close to 60% in five minutes.

Ray
 
garygid said:
Is it correct that the LEAF, when doing QC chaging:
1. stops at 80% if the QC charging started below 50%?
2. charges to 100% if the QC started over 50% SOC?

So, if starting a QC at 20%, a manual intervention (usually after the 80% is reached an the QC stops) is required to charge to 100%.
(eirher a manual Strat-Immediate button press in the LEAF, or perhaps a "Remote" Start-Charge command sent to the leaf)
1. Yes
2. Yes

In order to restart the charging process, you'll have to actually press the "Start" button on the DC Quick Charger.
 
garygid said:
Are QC "chargers" REQUIRED to have a Start button
(not self-starting by sensing a vehicle plugged in)?
Since the standard isn't public, I don't know. However, every DC Quick Charge station I've seen has had a Start button and the DC Quick Charge stations do not automatically start when you plug in a car (you've got to push the button)...
 
Just for completeness, I ran across the quote I remembered:
For motorists in a hurry, it is reassuring to know that on a quick charge the LEAF’s battery pack can recharge up to 60-65% in only 5 minutes.
From http://www.thegreencarwebsite.co.uk/blog/index.php/2011/02/21/in-conversation-with-nissans-francois-bancon/
 
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