The 40KWH Battery Topic

[DaveinOlyWA]

Her solutions are comical. Uneven cooling of the pack is not a good thing. She also spent only a relatively small time in Arizona.

whats worse is she was working nights driving Uber so was timing her full L2 charges to finish in the mid afternoon Sun of a Phoenix Summer (no garage, no shade, nada)

I am quite surprised her pack is still alive.

It is an interesting question whether she knew enough to time her charging so that the car would not sit fully charged for hours every day.

Oh she is VERY aware of all that. But she was still seeing very high temps BEFORE her first QC of the day. That is what started the AC venting and ice thing in the first place.

[SageBrush]

whats worse is she was working nights driving Uber so was timing her full L2 charges to finish in the mid afternoon Sun of a Phoenix Summer (no garage, no shade, nada)

I am quite surprised her pack is still alive.

It is an interesting question whether she knew enough to time her charging so that the car would not sit fully charged for hours every day.

Oh she is VERY aware of all that. But she was still seeing very high temps BEFORE her first QC of the day. That is what started the AC venting and ice thing in the first place.

Parking on asphalt in Phoenix

[DaveinOlyWA]

It is an interesting question whether she knew enough to time her charging so that the car would not sit fully charged for hours every day.

Oh she is VERY aware of all that. But she was still seeing very high temps BEFORE her first QC of the day. That is what started the AC venting and ice thing in the first place.

Parking on asphalt in Phoenix

Pretty much. An Apt dweller. She says there isn't even any shade. I can't imagine living in those conditions. I lived near Phoenix almost 40 years (and about 15º) ago and even the dump I lived in had covered parking.

[EnigmaEV]

After almost 10 months and 19,000 km (12,000 mi) my SOH has dropped to 94.35%. The fall has definitely slowed with winter temperatures below freezing but still continues with a .01% drop every few days and an occasional rapid drop of .25-.5%. The fully charged capacity, according to Leaf Spy, is 96.2% SOC, 92.6% GIDS, and 35.9 kWh.

For those interested in cold weather range, I drove a 106 km (66 mi) round trip last weekend in -29C (-20F) with a 15-20 kph (9-13 mph) crosswind, an average travel speed of 80 kph (50 mph), and interior temperature set to 18C (64F). I left fully charged, interior preheated, with an initial pack temperature of 2C (36F) and returned with 2% on the dash and a pack temperature of 16C (61F). I had passed Low Battery Warning and was about 6 km (4 mi) into Very Low Battery Warning. I'm not sure how far away I was from turtle. The interesting part is LeafSpy still showed 6.4 kWh remaining. Does anyone have a good idea how accurate LeafSpy is at lower states of charge? According to the car, about half way back, it determined I wouldn't be able to make it home. According to LeafSpy I had plenty of range to get back - which I did without any problems. LeafSpy also showed that I used 29.8 kWh on the trip which was confirmed with a 30.11 kWh charge back up to full. It is disappointing the car wants me to believe I can only use 78% of the supposed 38 kWh originally available, or 83% of the currently degraded battery. A 6 kWh buffer at the bottom end seems a little excessive.

[DaveinOlyWA]

After almost 10 months and 19,000 km (12,000 mi) my SOH has dropped to 94.35%. The fall has definitely slowed with winter temperatures below freezing but still continues with a .01% drop every few days and an occasional rapid drop of .25-.5%. The fully charged capacity, according to Leaf Spy, is 96.2% SOC, 92.6% GIDS, and 35.9 kWh.

For those interested in cold weather range, I drove a 106 km (66 mi) round trip last weekend in -29C (-20F) with a 15-20 kph (9-13 mph) crosswind, an average travel speed of 80 kph (50 mph), and interior temperature set to 18C (64F). I left fully charged, interior preheated, with an initial pack temperature of 2C (36F) and returned with 2% on the dash and a pack temperature of 16C (61F). I had passed Low Battery Warning and was about 6 km (4 mi) into Very Low Battery Warning. I'm not sure how far away I was from turtle. The interesting part is LeafSpy still showed 6.4 kWh remaining. Does anyone have a good idea how accurate LeafSpy is at lower states of charge? According to the car, about half way back, it determined I wouldn't be able to make it home. According to LeafSpy I had plenty of range to get back - which I did without any problems. LeafSpy also showed that I used 29.8 kWh on the trip which was confirmed with a 30.11 kWh charge back up to full. It is disappointing the car wants me to believe I can only use 78% of the supposed 38 kWh originally available, or 83% of the currently degraded battery. A 6 kWh buffer at the bottom end seems a little excessive.

how much of that 6.4 kwh left is usable depends on pack balance. You are likely gonna die at .2-.4 kwh left but could be as high as .6 kwh or more. I took mine to Turtle and 2.9% SOC (per LEAF Spy) with .6 kwh left. I might have been able to go another ½ mile at very slow speeds but wasn't interested.

As far as pack balance? I have done relatively few full charges so guessing my pack balance was fair at best. My pack voltage was 305 Volts so some life left but delta was 57 mV which I thought was pretty good considering how low I was.

[LeftieBiker]

After almost 10 months and 19,000 km (12,000 mi) my SOH has dropped to 94.35%. The fall has definitely slowed with winter temperatures below freezing but still continues with a .01% drop every few days and an occasional rapid drop of .25-.5%. The fully charged capacity, according to Leaf Spy, is 96.2% SOC, 92.6% GIDS, and 35.9 kWh.

For those interested in cold weather range, I drove a 106 km (66 mi) round trip last weekend in -29C (-20F) with a 15-20 kph (9-13 mph) crosswind, an average travel speed of 80 kph (50 mph), and interior temperature set to 18C (64F). I left fully charged, interior preheated, with an initial pack temperature of 2C (36F) and returned with 2% on the dash and a pack temperature of 16C (61F). I had passed Low Battery Warning and was about 6 km (4 mi) into Very Low Battery Warning. I'm not sure how far away I was from turtle. The interesting part is LeafSpy still showed 6.4 kWh remaining. Does anyone have a good idea how accurate LeafSpy is at lower states of charge? According to the car, about half way back, it determined I wouldn't be able to make it home. According to LeafSpy I had plenty of range to get back - which I did without any problems. LeafSpy also showed that I used 29.8 kWh on the trip which was confirmed with a 30.11 kWh charge back up to full. It is disappointing the car wants me to believe I can only use 78% of the supposed 38 kWh originally available, or 83% of the currently degraded battery. A 6 kWh buffer at the bottom end seems a little excessive.

That range makes sense, as it's almost exactly double the range of a 24kwh Leaf in similar conditions, with a similar SOH. The 40kwh Leaf has slightly less than double the capacity, but also higher efficiency on the highway because of better aerodynamics.

[cwerdna]

The interesting part is LeafSpy still showed 6.4 kWh remaining. Does anyone have a good idea how accurate LeafSpy is at lower states of charge?

I wouldn't take that as gospel. It's derived from the default of 77.5 watt-hours per gid * # of gids. You can make that kWh value go up/down by adjusting that constant via settings.

http://mynissanleaf.com/viewtopic.php?p=510091#p510091 is what wrote about gids and other values like SOH, Hx, and Ahr. Also see Turbo3's reply at March 15, 2018 at http://www.mynissanleaf.com/viewtopic.p ... start=1770. Sorry, I can't point to a direct post due to some site problem. The links end up jumping you to the wrong post.

An exact Wh is not going to be possible. They are all estimates. A battery is not like a gas tank.

LeafSpy uses two different ways to calculate Wh used. One is based on a change in Gids and the other is based on battery energy level changes.

Wh per Gid is not a precise number. The default is 77.5 Wh per Gid but you can change that in Settings/Battery. Also Gids when SOC is high seem to have less energy than Gids when SOC is low. After a full change the first bar goes away pretty quickly compared to later in the drive.

The Battery energy level has <1Wh resolution which looks great but a battery can change its available energy just by having the battery temperature increase or decrease. Battery energy level changes also includes all accessory energy use.

[DaveinOlyWA]

The interesting part is LeafSpy still showed 6.4 kWh remaining. Does anyone have a good idea how accurate LeafSpy is at lower states of charge?

I wouldn't take that as gospel. It's derived from the default of 77.5 watt-hours per gid * # of gids. You can make that kWh value go up/down by adjusting that constant via settings.

http://mynissanleaf.com/viewtopic.php?p=510091#p510091 is what wrote about gids and other values like SOH, Hx, and Ahr. Also see Turbo3's reply at March 15, 2018 at http://www.mynissanleaf.com/viewtopic.p ... start=1770. Sorry, I can't point to a direct post due to some site problem. The links end up jumping you to the wrong post.

An exact Wh is not going to be possible. They are all estimates. A battery is not like a gas tank.

LeafSpy uses two different ways to calculate Wh used. One is based on a change in Gids and the other is based on battery energy level changes.

Wh per Gid is not a precise number. The default is 77.5 Wh per Gid but you can change that in Settings/Battery. Also Gids when SOC is high seem to have less energy than Gids when SOC is low. After a full change the first bar goes away pretty quickly compared to later in the drive.

The Battery energy level has <1Wh resolution which looks great but a battery can change its available energy just by having the battery temperature increase or decrease. Battery energy level changes also includes all accessory energy use.

All the above basically illustrates how important it is to check your stats regularly and to get a baseline when you first receive the car. The default will work for 99% of everyone. Back in the day, the default was 80 wh/ GID (From GIDmeter) which was immediately discounted when LEAF Spy came out due to unrealistic full charge values.

There is nothing in your post that would suggest that your LEAF Spy settings are wrong.

Said it a million times and its well worth repeating; imm, the #1 values of LEAF Spy is actually knowing where your last mile is.

[EnigmaEV]

...how much of that 6.4 kwh left is usable depends on pack balance. You are likely gonna die at .2-.4 kwh left but could be as high as .6 kwh or more. I took mine to Turtle and 2.9% SOC (per LEAF Spy) with .6 kwh left. I might have been able to go another ½ mile at very slow speeds but wasn't interested.

As far as pack balance? I have done relatively few full charges so guessing my pack balance was fair at best. My pack voltage was 305 Volts so some life left but delta was 57 mV which I thought was pretty good considering how low I was.

Thanks for the extra insight. I didn't think to look at the voltage details during the drive. Here are some additional stats from the log file:

-Start of drive: 449 Gids, 399.65 V, 6 mV delta
-End of drive: 82 Gids, 335 V, 22 mV delta
-After recharge: 456 Gids, 402.43 V, 6 mV delta

The highest delta was 110 mV while travelling at 100 kph (62 mph) near the end of the trip. Shortly after slowing down to 60 kph (38 mph) the pack quickly balanced back down to 22 mV.

[DaveinOlyWA]

...how much of that 6.4 kwh left is usable depends on pack balance. You are likely gonna die at .2-.4 kwh left but could be as high as .6 kwh or more. I took mine to Turtle and 2.9% SOC (per LEAF Spy) with .6 kwh left. I might have been able to go another ½ mile at very slow speeds but wasn't interested.

As far as pack balance? I have done relatively few full charges so guessing my pack balance was fair at best. My pack voltage was 305 Volts so some life left but delta was 57 mV which I thought was pretty good considering how low I was.

Thanks for the extra insight. I didn't think to look at the voltage details during the drive. Here are some additional stats from the log file:

-Start of drive: 449 Gids, 399.65 V, 6 mV delta
-End of drive: 82 Gids, 335 V, 22 mV delta
-After recharge: 456 Gids, 402.43 V, 6 mV delta

The highest delta was 110 mV while travelling at 100 kph (62 mph) near the end of the trip. Shortly after slowing down to 60 kph (38 mph) the pack quickly balanced back down to 22 mV.

Yeah, not sure I would consider any reading of the delta while moving. I think there is a large disconnect between reality and the sluggish actions of the LEAF BMS/LBC... just another chink in the amor, I think.