62kwh Leaf Plus Efficiency Posting

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SageBrush said:
DougWantsALeaf said:
It seems you could build a single piece top battery cover with a molded heat exchanging set of small tubes and then put a small fan in the pack to push the air across those tubes. Even a modest amount of additional cooling would make long distances less frustrating.

The only practical way I can think of to mitigate rapid-gating from serial DC fast charging is to drive slowly. 55 mph Vs 70 mph would be close to 40% less pack heat generation. And somewhat paradoxically but for similar reasons, you may want to to avoid charging in the low SoC range so that the car keeps to lower charging amperage.

From from great, but I think travel times better than what you and others have posted are possible. When it comes to the LEAF, patience is a virtue :lol:

Yes, this has been stated many times, but they never seem to understand even a little of thermodynamics.
There's always a new way to cool or minimize increasing battery heat that hasn't been thought of, right?
 
This makes me wonder. What if someone manufactured a replacement lower half for the battery clam-shell using heat dispersing material and heat sink like fins etc. Wonder if it would help much.
 
OldManCan said:
This makes me wonder. What if someone manufactured a replacement lower half for the battery clam-shell using heat dispersing material and heat sink like fins etc. Wonder if it would help much.

You are aware that "heat sink fins" increase the surface area of what's attached to the fins, right?
And as such, the fins can also cause the device they're attached to increase in temperature sooner,
assuming the device is initially at a lower temperature than ambient, e.g. an initially low temp
parked Leaf being driven in a hot ambient.

Anyway, the use of fins for a Leaf battery is laughable, given the thermal mass of the Leaf battery,
notwithstanding the size of the fins necessary, but also the practical placement of the fins.
 
lorenfb said:
Anyway, the use of fins for a Leaf battery is laughable, given the thermal mass of the Leaf battery,
notwithstanding the size of the fins necessary, but also the practical placement of the fins.

Copy that. Mine was an uneducated wondering. Case closed.
 
Have to do some digging but did the slow drive with VERY mixed results.

The key to heat is limiting DC charging levels. Tried "nearly" same trip under "similar" circumstances 3 times but vastly different driving

Trip 1; Mixed driving speeds due mostly to traffic which was severe in places. Left home, low SOC, charged to 65% more or less 4 times en route with one charge stop due to extreme personal need so gained only 6 or 7 kwh there. Batt temps hit low 100's, OAT near 90 (probably a bit over during the middle of the day on asphalt)

Trip 2; Same destination but took different slower route with less charging options. Left home with full charge, stopped twice charging to 80ish% one time, 75% the 2nd, Batt temps mid to high 110's OAT 85 Both charges started below 15% SOC (spent night)

Trip 3; Different destination about 40 miles longer overall. Full charge leaving home, 2 enroute one for personal break to 50ish% the other to 70%. Then spent day hiking, left, hit dinner and charge to high 60's % then sprint home hitting 70 mph, OAT over 100º. Batt temps low 100's.

Although not notated (still have LEAF Spy logs) it appears the best way to reduce heat is stop DC charges at no more than 60-70%. More than a bit inconvenient. When I exceeded that, the slowdown on 100 Kw stations were extreme with charging knee as low as 30 %. 50 KW stations weren't too bad with ~ 5 kw slowdown or less.
 
OldManCan said:
This makes me wonder. What if someone manufactured a replacement lower half for the battery clam-shell using heat dispersing material and heat sink like fins etc. Wonder if it would help much.

I think the most effective way is venting at the top fan driven but the incoming air would need to be vented in creating a challenge for moisture. The Soul EV vented from the passenger space like the Prius so yeah, that would be one idea anyway. I know a Souler who was an EXTENSIVE road tripper who wore a coat all summer long due to the fact he drove 70 plus all the time with A/C cranking.
 
For most driving needs forced air cooling would be enough. Who's brave enough to drill the holes in their Leaf Battery case? That's essentially how the eNV200 battery cooling works.
 
The LEAF pack over-heating is such a massive negative, I find it hard to believe that Nissan would not have implemented any easy/cheap solutions years ago.
 
SageBrush said:
The LEAF pack over-heating is such a massive negative, I find it hard to believe that Nissan would not have implemented any easy/cheap solutions years ago.

Why? The Plus model has worked great for me in Phoenix for almost 3 years and over 50,000 miles. I expect quite a while before the first capacity bar is lost and a long time before deterioration is enough to impact my use. The simplicity and efficiency of passive air cooling is an advantage to me. Deterioration (reduced capacity) that I have been able to measure so far is similar to that measured by a major automotive magazine after two years of use of a Model 3 Tesla.
 
I treat my SV+ best I can against heat here in Houston Texas area - with shady parking, cooler evening air into the garage - exclusive night home charging, mostly low- mid SOCs, etc, etc. It's a great vehicle in so many ways (and was inexpensive) - but I'm retired and can "baby" it as I see fit. Would I recommend for everyone - no way!
 
What it boils down to is that the Leaf isn't a good car for road tripping when multiple DCFC sessions are required in one day. If you don't need more than a single QC session, to extend the range a bit, then it's a very good car if you like traditional cars.
 
GerryAZ said:
SageBrush said:
The LEAF pack over-heating is such a massive negative, I find it hard to believe that Nissan would not have implemented any easy/cheap solutions years ago.

Why? The Plus model has worked great for me in Phoenix for almost 3 years and over 50,000 miles. I expect quite a while before the first capacity bar is lost and a long time before deterioration is enough to impact my use. The simplicity and efficiency of passive air cooling is an advantage to me. Deterioration (reduced capacity) that I have been able to measure so far is similar to that measured by a major automotive magazine after two years of use of a Model 3 Tesla.

Agreed. The over heating is only an issue on long drives and the plus requires it to be a VERY long drive. Granted, conditions and driving styles vary but it actually is possible to drive 400 miles with minimal issues. I have done it twice. I had to work pretty hard to have "issues" including leaving home at 12% SOC which is probably not recommended with a goal of driving 375 miles that day.

I know 375 is a paltry amount for many but that is pretty much my limit. I did 500 miles in my 40 kwh in a day testing Webasto compatibility and that was way too many miles. Luckily, the scenery helped me survive.
 
DaveinOlyWA said:
The over heating is only an issue on long drives and the plus requires it to be a VERY long drive.

Only an issue *for you, given your expectations.*

Drive 400 miles a day at 75 mph. How much time do you spend charging ?
Now tell us day #2 with the same driving, without overnight charging.
In the summer

And of course this all presumes that the DC charging is located where you want it, is available, and is reliable. Which in the case of CHAdeMO is a *huge* ymmv

Gerry likes to tout how well the LEAF works for him, but he rarely mentions his other ICE vehicles for trips outside of commuting duties. That said, I was pretty darned sure that the higher capacity LEAFs would have even worse heat related battery degradation than the 2013 - 2017 LEAFs and I'm happy to say that I was wrong. So wrong, in fact, that I would consider buying a 40 or 62 kWh CCS LEAF for 'extended commuting duties'. That is saying something, considering my extremely negative opinion of Nissan corporate and its dealerships.
 
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