LeftieBiker
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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Wed Apr 11, 2018 10:26 pm

How about "DCFOC" for "DC Fast ONCE Charging"?
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
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PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

cwerdna
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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 1:34 am

SageBrush wrote:The 2018 LEAF DCFC should come with a big footnote that reads "up to 45 kW, as battery temperature and other variables allows."

Or just give up on the DCFC sham altogether and advertise DC L2+ speeds

Perhaps we need a new acronym: DCSC "DC slow charging."
FWIW, in Japan, they have "intermediate" (CHAdeMO) chargers.

See https://teslamotorsclub.com/tmc/threads ... ost-961564 and https://teslamotorsclub.com/tmc/threads ... ost-971287. As the 2nd post mentions, they even have some 10 kW CHAdeMO chargers there.

'19 Bolt Premier
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

JeffN
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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 11:38 am

DaveinOlyWA wrote:throttling starts on QC if temp is over about 85º which is almost always going to be the 2nd session but its relatively minor with 16-17 kwh received in 30 mins instead of 22 kwh for a first charge.

The reality is it would not be good for a road trip in Summer over 300 miles. Under that, the additional range more than makes up for the charging speed.

FYI; This sounds bad but puts it on near equal footing with the Bolt. I saw a Bolt charging in temps low 70's in Sept pulling 130 amps from EVGO. I was impressed until it hit 55% and the charge rate dropped like a rock to 62 amps. It was... SHOCKING
Sorry, I’m just following this thread now so I’m catching up from earlier comments like this one.

Saying that the 2018 LEAF is nearly on the same footing as the Bolt EV for long-distance driving of 300 miles or more is misleading.

I’ve done many road trips since getting my own Bolt in January of 2017 and almost all of the charging during the drive was on 50 kW DC chargers. I’m very familiar with the Bolt’s rampdown pattern. I have even fast charged in Las Vegas at 104F after several hours of driving from near Los Angeles and have not seen a noticeable slowdown due to heat because the TMS does a good job of keeping pack temperatures not much warmer than 86F.

From memory it looks roughly like this:

0-54% at 53 kW or 150A (125A on today’s chargers)
55-68% at 37 kW or 100A
69-84% at 24 kW or 60A
85-92% at 16 kW at 40A

I rarely QC much above 80% so that last line may be slightly off.

So, “dropped like a rock” seems misleading to me.

Even though the Bolt begins ramping down the charge current aggressively at 55% its battery is quite a bit larger in capacity so on road trips its typical to add roughly 80 to 100 miles with a 30 minute charge at an average of around 43 kW on today’s chargers which appears to be at least as fast as a new LEAF can do when not restricted and twice the speed of a heat-restricted LEAF charging.

I have no qualms doing 400 to 500 mile daily segments in hot summer weather while it appears that would be rather tedious in the new LEAF, as you noted.

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IssacZachary
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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 4:33 pm

It sounds like all Leafs from all years and battery sizes thus far would be much better cars if someone would just figure out a way to install a fan that blows fresh air over the traction battery. It might not be enough cooling for those that live in extremely hot areas but it would be better than nothing and might be sufficient in most areas due to the overall thermal stability Nissan designed into all Leaf batteries. The battery fan could even be left on for extended periods by means of a 12V solar panel on the roof.

I just remembered I have a 12V blower just lying in the shed. It or two of them might fit between the traction motor assembly and fire wall. Then I'd just have to figure out the duct work and where the fresh air would come in at (hood scoop maybe?!). Now I want to go grab it and see if I can fit it in there somehow.
2013 SL SOLD :cry:
2013 Toyota Avalon Hybrid CURRENT

SageBrush
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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 8:13 pm

IssacZachary wrote:It sounds like all Leafs from all years and battery sizes thus far would be much better cars if someone would just figure out a way to install a fan that blows fresh air over the traction battery. It might not be enough cooling for those that live in extremely hot areas but it would be better than nothing and might be sufficient in most areas due to the overall thermal stability Nissan designed into all Leaf batteries. The battery fan could even be left on for extended periods by means of a 12V solar panel on the roof.

I just remembered I have a 12V blower just lying in the shed. It or two of them might fit between the traction motor assembly and fire wall. Then I'd just have to figure out the duct work and where the fresh air would come in at (hood scoop maybe?!). Now I want to go grab it and see if I can fit it in there somehow.
This idea pops up all the time, but if it was that easy and cheap Nissan would have done it.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

lorenfb
Posts: 2426
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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 8:20 pm

IssacZachary wrote:It sounds like all Leafs from all years and battery sizes thus far would be much better cars if someone would just figure out a way to install a fan that blows fresh air over the traction battery. It might not be enough cooling for those that live in extremely hot areas but it would be better than nothing and might be sufficient in most areas due to the overall thermal stability Nissan designed into all Leaf batteries. The battery fan could even be left on for extended periods by means of a 12V solar panel on the roof.

I just remembered I have a 12V blower just lying in the shed. It or two of them might fit between the traction motor assembly and fire wall. Then I'd just have to figure out the duct work and where the fresh air would come in at (hood scoop maybe?!). Now I want to go grab it and see if I can fit it in there somehow.
Remember, to remove heat from the battery cells you have three thermal resistances (inverse of thermal conductance) to contend with,
i.e. cells to battery case, battery case to vehicle chassis, chassis to ambient. The last has the lowest thermal resistance. The next lowest is
the battery case to chassis. The most problematic thermal resistance is the cells to battery case. So blowing ambient air on the battery case
will have negligible effect on reducing the cells temperature. That's why an effective TMS has to be integrated into the design of the battery.
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

SageBrush
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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 8:29 pm

lorenfb wrote:
IssacZachary wrote:It sounds like all Leafs from all years and battery sizes thus far would be much better cars if someone would just figure out a way to install a fan that blows fresh air over the traction battery. It might not be enough cooling for those that live in extremely hot areas but it would be better than nothing and might be sufficient in most areas due to the overall thermal stability Nissan designed into all Leaf batteries. The battery fan could even be left on for extended periods by means of a 12V solar panel on the roof.

I just remembered I have a 12V blower just lying in the shed. It or two of them might fit between the traction motor assembly and fire wall. Then I'd just have to figure out the duct work and where the fresh air would come in at (hood scoop maybe?!). Now I want to go grab it and see if I can fit it in there somehow.
Remember, to remove heat from the battery cells you have three thermal resistances (inverse of thermal conductance) to contend with,
i.e. cells to battery case, battery case to vehicle chassis, chassis to ambient. The last has the lowest thermal resistance. The next lowest is
the battery case to chassis. The most problematic thermal resistance is the cells to battery case. So blowing ambient air on the battery case
will have negligible effect on reducing the cells temperature. That's why an effective TMS has to be integrated into the design of the battery.
And yet driving is pretty effective compared to standing still, at least in the 24 kWh packs.
My take on this question is that parking in an unventilated space like a closed garage is a BAD idea; but once outside I doubt a fan is going to help much.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

User avatar
IssacZachary
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Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 8:37 pm

Isn't there a space above and below the battery for cooling purposes? I don't recall that heat has to travel through the chasis to exit the battery.

Anyhow, it's not a lot of heat that needs to be removed.
2013 SL SOLD :cry:
2013 Toyota Avalon Hybrid CURRENT

lorenfb
Posts: 2426
Joined: Tue Dec 17, 2013 10:53 pm
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Leaf Number: 416635
Location: SoCal

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 8:40 pm

SageBrush wrote:
lorenfb wrote:
IssacZachary wrote:It sounds like all Leafs from all years and battery sizes thus far would be much better cars if someone would just figure out a way to install a fan that blows fresh air over the traction battery. It might not be enough cooling for those that live in extremely hot areas but it would be better than nothing and might be sufficient in most areas due to the overall thermal stability Nissan designed into all Leaf batteries. The battery fan could even be left on for extended periods by means of a 12V solar panel on the roof.

I just remembered I have a 12V blower just lying in the shed. It or two of them might fit between the traction motor assembly and fire wall. Then I'd just have to figure out the duct work and where the fresh air would come in at (hood scoop maybe?!). Now I want to go grab it and see if I can fit it in there somehow.
Remember, to remove heat from the battery cells you have three thermal resistances (inverse of thermal conductance) to contend with,
i.e. cells to battery case, battery case to vehicle chassis, chassis to ambient. The last has the lowest thermal resistance. The next lowest is
the battery case to chassis. The most problematic thermal resistance is the cells to battery case. So blowing ambient air on the battery case
will have negligible effect on reducing the cells temperature. That's why an effective TMS has to be integrated into the design of the battery.
And yet driving is pretty effective compared to standing still, at least in the 24 kWh packs.
My take on this question is that parking in an unventilated space like a closed garage is a BAD idea; but once outside I doubt a fan is going to help much.
Right. Then there's the thermal time constant, i.e. the time for the cells' temperatures to reach ambient - assuming a higher temp (from driving/charging).
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

lorenfb
Posts: 2426
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Possible Widespread 2018 Traction Battery Quick Charge Problems

Thu Apr 12, 2018 8:43 pm

IssacZachary wrote:Isn't there a space above and below the battery for cooling purposes? I don't recall that heat has to travel through the chasis to exit the battery.
You need to know how the battery is attached to the chassis.
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 10.3K miles, SOH 109Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F

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