Heh. When I looked at the new tires I saw the fine print that says "Do not exceed 40 PSI when seating bead" or something to that effect, and stopped reading before the final clause. My excuse is that it was upside down at the time, so reading backwards I was not at my best.DaveinOlyWA said:Those are OEMs and my cold pressure target is always the Max sidewall pressure. Can't remember the last time I saw a passenger tire with 40 PSI listed. (if ever?)
BuckMkII said:Heh. When I looked at the new tires I saw the fine print that says "Do not exceed 40 PSI when seating bead" or something to that effect, and stopped reading before the final clause. My excuse is that it was upside down at the time, so reading backwards I was not at my best.DaveinOlyWA said:Those are OEMs and my cold pressure target is always the Max sidewall pressure. Can't remember the last time I saw a passenger tire with 40 PSI listed. (if ever?)
I thought that was weird, since all the other tires I can remember having lately were max around 44 PSI, but I was too dumb to read ALL of the sidewall text.
Time to get out the ol' Zefal Double-Shot floor pump! Not that I need to eke out every mile. We drive the car only 15 to 40 miles per day, almost without exception.
johnlocke said:Same dimensions but higher energy density. 40KWH vs 30KWH or 24KWH. Not a huge effect while driving (lots of airflow around the battery) but a substantial difference while charging (longer charge time and no airflow to dissipate heat buildup). Unless you intentionally limit the battery capacity (I.E. 12% to 88%) there will be more heat buildup due to a longer charge time. Plus the fact that you are likely to charge it to 100% from a low state(30% or less). This likely to really problematic if you are DCFC'ing on a trip. With the 30KWH battery, adding 2 temp bars during fast charging is common. I expect it to be worse with 40KWH battery. Add in the heating effect from high discharge rates from freeway driving and long trips encouraged by the longer range battery and you could have a recipe for a disaster.
borugee said:johnlocke said:Same dimensions but higher energy density. 40KWH vs 30KWH or 24KWH. Not a huge effect while driving (lots of airflow around the battery) but a substantial difference while charging (longer charge time and no airflow to dissipate heat buildup). Unless you intentionally limit the battery capacity (I.E. 12% to 88%) there will be more heat buildup due to a longer charge time. Plus the fact that you are likely to charge it to 100% from a low state(30% or less). This likely to really problematic if you are DCFC'ing on a trip. With the 30KWH battery, adding 2 temp bars during fast charging is common. I expect it to be worse with 40KWH battery. Add in the heating effect from high discharge rates from freeway driving and long trips encouraged by the longer range battery and you could have a recipe for a disaster.
Does Leaf battery getting cooled from airflow? What I am noticing is once temp go high, it do not seems to come down that easily even when driving. When 2 bars go up during QC, they don't come down ever if you drive slow (ECO).
After left parking it take 24Hrs or so to cool down. I think these batteries are very well insulated.
Can someone explain if there is any air cooling (passive) going on with these Leaf Packs or battery enclosure is fully sealed and no air can get it?
borugee said:johnlocke said:Same dimensions but higher energy density. 40KWH vs 30KWH or 24KWH. Not a huge effect while driving (lots of airflow around the battery) but a substantial difference while charging (longer charge time and no airflow to dissipate heat buildup). Unless you intentionally limit the battery capacity (I.E. 12% to 88%) there will be more heat buildup due to a longer charge time. Plus the fact that you are likely to charge it to 100% from a low state(30% or less). This likely to really problematic if you are DCFC'ing on a trip. With the 30KWH battery, adding 2 temp bars during fast charging is common. I expect it to be worse with 40KWH battery. Add in the heating effect from high discharge rates from freeway driving and long trips encouraged by the longer range battery and you could have a recipe for a disaster.
Does Leaf battery getting cooled from airflow? What I am noticing is once temp go high, it do not seems to come down that easily even when driving. When 2 bars go up during QC, they don't come down ever if you drive slow (ECO).
After left parking it take 24Hrs or so to cool down. I think these batteries are very well insulated.
Can someone explain if there is any air cooling (passive) going on with these Leaf Packs or battery enclosure is fully sealed and no air can get it?
The pack is designed to be submersible and waterproof, as well as impervious to air.DaveinOlyWA said:..the pack is all but submersible and waterproof
...though, I certainly expect improvements were made.edatoakrun said:BEV designers take varying (by both kW rate and temperature) rates of impedance into account in designing BEV battery packs and drive-trains.lorenfb said:...Besides having an effect on battery life, the battery chemistry also affects the internal impedance of each cell.
As has been noted on this forum, the original Tesla MS/X cell exhibits a significantly greater internal impedance
than the Leaf's. So at the same cell currents, the Tesla cells will develop more heat, increasing the necessity
for TMS for the Tesla versus for the Leaf.
2011-17 LEAF packs depend on this passive heat source for their battery heating needs, to keep the pack higher up in the temperature range, giving higher kWh capacity than that available from colder packs.
A major reason for the observable lower efficiency in m/kWh when driving colder temperatures is the greater amount of energy diverted to pack heating, both when charging and discharging, when the pack is colder.
The presumably larger thermal mass of the larger 2018-on LEAF pack(s) should allow them to retain heat longer, a net positive for operating efficiency.
The lower C rate of the larger packs, during both charge and discharge cycles, should also lower the amount of undesirable heat generated under the relatively unusual conditions (pack temperatures exceeding ~90 F to 100 F) when additional pack heating is undesirable.
So we should expect 2018-on LEAF packs to operate more efficiently and lose capacity at a lower rate than earlier lower kWh packs, even if AESC had made no improvements at all in cell chemistry.
LKK said:I read this curious statement in Inside EVs story on the expansion of the Nissan battery plant.
"Editor’s Note: It is our assumption that Nissan will be using LG Chem batteries for the longer range, ~60 kWh/225 mile that arrives later next year as a 2019 model year offering (the ID Concept’s 60 kWh battery was co-developed with LG Chem), and that Nissan’s deal to sell GSR its battery business is also contingent upon them being the sole battery provider (40 kWh) for the 2018 model year LEAF."
I didn't know the 60 kwh battery was going to be produced by LG. LG makes a lot of subsystems for the Bolt including the battery and it's thermal management system. Do you think LG cut Nissan a sweet deal to abandon their own battery and use a 60 kwh battery and thermal management system derived from the Bolt?
Why do those who have such serious anxiety regarding battery temperatures in passively manged packs keep buying LEAFs, and continue sharing their insecurities on this forum?johnlocke said:All Leaf's rely on convection cooling of the sealed battery pack. Most of that is provided by airflow across the bottom of the battery. Although the battery does bolt onto the chassis there are no thermal pads to provide a heat path to the chassis and the bolt pads provide only a small contact area for heat transfer. It is safe to say that the major cooling effect is by convection and is only effective when the car is moving.
Nissan sealed the battery packs to prevent corrosion and contain any battery fluid leaks. Their cooling solution is adequate for the British Isles and Europe. It even works in the northern half of the U.S. for the most part. It is not suitable for the southern half of of the U.S.
When you burn your finger, do you blow on it to cool it off or do you hold it still in stagnant air? The battery takes literally hours to cool when sitting still overnight even when the temps are significantly lower. While there is some cooling effect in stagnant air, convection cooling works best when there is moving air. That's why your computer has fans inside. To move air around and exhaust heated air from the system.edatoakrun said:You have packed quite a bit of misinformation in your post below.
Next time you park your LEAF with the battery temperature significantly above ambient, watch the rate at which the pack temperature declines to see for yourself that this statement is false.
Why do those who have such serious anxiety regarding battery temperatures in passively manged packs keep buying LEAFs, and continue sharing their insecurities on this forum?johnlocke said:All Leaf's rely on convection cooling of the sealed battery pack. Most of that is provided by airflow across the bottom of the battery. Although the battery does bolt onto the chassis there are no thermal pads to provide a heat path to the chassis and the bolt pads provide only a small contact area for heat transfer. It is safe to say that the major cooling effect is by convection and is only effective when the car is moving.
Nissan sealed the battery packs to prevent corrosion and contain any battery fluid leaks. Their cooling solution is adequate for the British Isles and Europe. It even works in the northern half of the U.S. for the most part. It is not suitable for the southern half of of the U.S.
edatoakrun said:Why do those who have such serious anxiety regarding battery temperatures in passively manged packs keep buying LEAFs, and continue sharing their insecurities on this forum?
GerryAZ said:Passive battery cooling is the best option for my usage pattern so I accept some deterioration over time. I will not buy an EV that has battery chemistry which requires active cooling even when parked. My 2015 LEAF is doing much better than the 2011 (both original and replacement batteries). I am disappointed to hear of so many 30 kWh batteries in milder climates losing capacity bars at low mileage. My 2015 with original battery has 48,653 miles and 11 capacity bars right now as I am using the third QC in the past 8 hours. It is clear that I will be far beyond the capacity warranty end at 60,000 miles before it is down to 8 bars (unless capacity starts dropping rapidly).
Not insecurities, disappointment with how fast the battery is aging.edatoakrun said:Why do those who have such serious anxiety regarding battery temperatures in passively manged packs keep buying LEAFs, and continue sharing their insecurities on this forum?
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