Rapid charge loss

I just bought a 2019 Nissan Leaf and I'm a little concerned about my battery charge dropping dramatically to 0% in just a few miles. Twice now I've left the house with about 50% left on the battery charge indicator. I live in Colorado and work in the foothills near Denver. My commute is 11.5 miles/18.5 Kilometers. The first 3 miles are on residential streets and 8.5 miles are on highway. Once I get on the highway there are about 6 miles of relatively steep hill to climb. With a full charge I will use 16-18% of my charge depending on whether or not I have the heated seat on low and the heated steering wheel on. If I start out with 50% or less on the charge indicator it can go from 44% (approx. what's left when I start the hill climb) all the way to 0% within a couple of miles and a couple of minutes of starting the hill climb. The car will slow down and enter turtle mode and I have to limp the remaining 3 miles to work . My speed is typically 65 mph / 104 kph, outside temperatures have varied from 25F/-3C to 40F/5C, eco mode is on, the heater is off, heated steering wheel is off and the heated seat is off. I've been trying to only charge the battery to 80% and not let it drop below 20%, but that is really hard to do when the charge plummets so quickly. Is this normal to have such a dramatic difference between the charge used when fully charged vs the charge used when half way charged when climbing a hill?

No, not at all normal. Your car likely has a bad cell or two in the pack, and the pack almost certainly will be replaced. Get it to a dealer ASAP.

MrB01112 said:

I just bought a 2019 Nissan Leaf and I'm a little concerned about my battery charge dropping dramatically to 0% in just a few miles. Twice now I've left the house with about 50% left on the battery charge indicator. I live in Colorado and work in the foothills near Denver. My commute is 11.5 miles/18.5 Kilometers. The first 3 miles are on residential streets and 8.5 miles are on highway. Once I get on the highway there are about 6 miles of relatively steep hill to climb. With a full charge I will use 16-18% of my charge depending on whether or not I have the heated seat on low and the heated steering wheel on. If I start out with 50% or less on the charge indicator it can go from 44% (approx. what's left when I start the hill climb) all the way to 0% within a couple of miles and a couple of minutes of starting the hill climb. The car will slow down and enter turtle mode and I have to limp the remaining 3 miles to work . My speed is typically 65 mph / 104 kph, outside temperatures have varied from 25F/-3C to 40F/5C, eco mode is on, the heater is off, heated steering wheel is off and the heated seat is off. I've been trying to only charge the battery to 80% and not let it drop below 20%, but that is really hard to do when the charge plummets so quickly. Is this normal to have such a dramatic difference between the charge used when fully charged vs the charge used when half way charged when climbing a hill?

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First guess is you have one or more bad cells in the battery, or the battery is very badly out of balance, or both. Not normal.

BTW: Heated seats and steering wheel consume close enough to zero power to ignore, 100 watts rather than the multiple kW the motor uses.

Hmmm, interesting. Guessing you don't have LEAF Spy which would tell us a lot about whats going on. Your SOC drops to zero on the hills but guessing that recovers quite nicely by the time you head home in the afternoon?

What is SOC/ GOM (range estimate) When leaving home, parking at work, leaving work and arriving home?

Your statement of losing 6% SOC by the time you get to the hill is a bit weird as well especially with 3 miles of street level speed that I am guessing is relatively flat. Its not cold enough to be a factor. Is car garaged? What is batt temps?

It does sound like an out of balance cell but its a bit "weird" for your SOC to register zero% on a bad cell as I have seen people go from 40% SOC immediately into Turtle on a bad cell...

Wondering if the pack is too cold to put out enough power to climb the hill?

No, I don't have Leaf Spy. Normally I can recover about 2-3% of the charge on the way home.

I'm not sure of the SOC/GOM during the first incident other than the SOC was at 44% when I left the house. The SOC/GOM when leaving the house the other day was 48%/~77 mile range.

Something that I should have mentioned in my first post was that after it started slowing down and the SOC just read "---", I was able to get off the highway and jump over to the service road. Once I slowed down to about 35 the SOC started to bounce back to 22% and was at 19% when I made it to work.

When I left work the SOC was still at 19% and when I arrived home it was up to 22%.

The residential roads are relatively flat. Normally I would loose about 1-2% getting to the highway and then the other 4% on relatively flat highway getting to the base of the hill. The car is not garaged, just parked under a carport. I'm not sure what the battery temp was but I would guess around 15-25F, as it does get fairly cold at night.

Thanks for the suggestion of Leaf Spy. I will look into getting that and hopefull gather more data.

MrB01112 said:

No, I don't have Leaf Spy. Normally I can recover about 2-3% of the charge on the way home.

I'm not sure of the SOC/GOM during the first incident other than the SOC was at 44% when I left the house. The SOC/GOM when leaving the house the other day was 48%/~77 mile range.

Something that I should have mentioned in my first post was that after it started slowing down and the SOC just read "---", I was able to get off the highway and jump over to the service road. Once I slowed down to about 35 the SOC started to bounce back to 22% and was at 19% when I made it to work.

When I left work the SOC was still at 19% and when I arrived home it was up to 22%.

The residential roads are relatively flat. Normally I would loose about 1-2% getting to the highway and then the other 4% on relatively flat highway getting to the base of the hill. The car is not garaged, just parked under a carport. I'm not sure what the battery temp was but I would guess around 15-25F, as it does get fairly cold at night.

Thanks for the suggestion of Leaf Spy. I will look into getting that and hopefull gather more data.

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Yeah, I would take it in. A bad cell creates more bad cells. I predict you will be stranded here in the next few weeks if you let it go.

The part about regaining SOC at slower speeds still suggests a cold pack but even at 15º your pack shouldn't be "that" bad... (I hope!) but its not a completely out of the World possibility either...

You should be doing a full charge at least once every 10 days to balance the pack. You do not have hot weather, and you have a hill climb during your travel, and you are doing it at higher speeds. There is no real reason to not let it charge to 100% every night. If you are concerned about the time it sits at 100%, then use the Charge timer so it finishes 30-60 minutes prior to departure. Use the Climate Control timer to preheat the car at least 20 minutes before departure, so there is less drain on the battery from the heater.

You may have an issue with defective cells in the pack. Charge it to full a few times and get the pack balanced, and then see if it behaves any better. If not, take it to the dealer for a checkup.

The battery is defective due to bad cell(s).
Take the car in for service yesterday. Don't wait for LeafSpy

Thank you all for your feedback. I've order Leaf Spy and the OBDII scanner to go with it. I've also made an appointment with my dealership to have it looked at next Wednesday. I'm finding that there is a bit of a learning curve to owning an electric vehicle, so thank you all, your input is very much appreciated. Once I get it back from the service department I'll add a follow-up post with the result.

I have a 2019 Leaf with just over 4,000 miles. I just had a similar experience. I have one steep hill to climb about 15 miles before I reach my work. This morning, the low battery warning went off as I started climbing the hill and I watched the battery charge indicator drop about 10% in 10 seconds. I immediately slowed down while still climbing the hill, and the indicator quickly climbed from 1 to 11% charge. Leafspy said I had >100 GIDs so I didn't really worry. The rest of my drive was normal and I made it to work with no issues. This is the first time this has happened though I have climbed the same hill a dozen times with a similar state of charge. I was however going very fast and facing an unusually strong headwind (40-50 mph) and I didn't have to slow down much before the charge reading recovered. It may be a software issue as Leafspy didn't indicate anything unusual and the pack was still well balanced, but I'll probably take it in and have it checked just the same.

^^ You and OP are noticing the same physics: voltage drops under load.
You also have one or more bad cells.

Get your car to a dealership, and do not let them tell you that the pack voltage is OK. They need to check for bad cell(s)
A test drive accelerating up a long, steep hill is an easy way to show a skeptical tech that a defect exists.

There is an article on the web by Brad Berman describing two battery replacements in his Chevy Bolt, each time due to one bad cell in the pack. This is a manufacturing QC issue in the Bolt battery, and the same general problem is now getting exposure in the '18 LEAF.

The only surprising thing to me actually is that Tesla does not have an even bigger problem with low frequency cell defects leading to poor pack performance since a Tesla has 10x more cells and presumably a 10x greater likelihood of a defective pack, all else being equal. They must have absolutely outstanding manufacturing and QC. That was hinted at by a Sandy Munro tear-down that reported less than 0.2 mv* difference between cells (or perhaps groups of cells -- I am not sure.) That level of manufacturing is no doubt good for pack longevity but it also may be a requirement to identify and wean out the weak cells before they are put in packs.

*For some perspective, Nissan spec allows somewhere in the range of 200 - 300 mv delta between cell pairs. So a good 1000x difference in manufacturing tolerance and QC.

More cells will increase the probability of defects, but more cells in parallel may also mask their effect. Some defects like excessive self-discharge will still push the pack out of balance, but high internal resistance or reduced capacity in one cell of a group of 10 or 20 will be much less noticeable than in one cell of a group of two.

I was able to observe the same issue again. This is what I found. With the cruise control set at high speed (75 mph) on a steep hill, the car was maxing out the available power bars. This high power caused the SOC to immediately start dropping, at about 1% SOC every second or so. As soon as I reduced power a little, the SOC quickly returned to its prior value, increasing about 10% in one second or so. Leafspy didn't indicate any bad cells and did not show the SOC or GIDs dropping like the dash display did.

Since the car is only 2 months old, I'll have the battery checked out.

blakem said:

I was able to observe the same issue again. This is what I found. With the cruise control set at high speed (75 mph) on a steep hill, the car was maxing out the available power bars. This high power caused the SOC to immediately start dropping, at about 1% SOC every second or so. As soon as I reduced power a little, the SOC quickly returned to its prior value, increasing about 10% in one second or so. Leafspy didn't indicate any bad cells and did not show the SOC or GIDs dropping like the dash display did.

Since the car is only 2 months old, I'll have the battery checked out.

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Likely another symptom of "IceGate"

Too bad its too late to test that this year... Oh well, maybe next year.

https://daveinolywa.blogspot.com/2018/12/cold-verses-leaf.html

Well, I took my car to the dealership to have it looked at. I brought it into them with about 63% charge on it. They said they drove it around and were unable to duplicate the problem. I asked them if they took it up the highway and climbed the steep grade and they had not. They just drove it around town locally, couldn't find a problem and plugged it in when they brought it back. I told them that it only shows a problem on a steep grade going 65 mph, with a charge below 50%. They drove the car around to discharge it and then tried driving it up the hill with a 50% charge and were still unable to duplicate the problem.

They also hooked it up to there computer to analyze the state of the cells and were unable to see any issues. My gut feeling is that they probably won't see anything unless the battery is under extreme load.

In any case, I did get the Leafspy app and the OBDII sensor so I'm hoping that I might be able to keep that going the next time I get down below that 50% SOC so I might be able to record some data for them, and maybe get some video.

The battery pack may have to be under extreme load AND be very cold.

Get video of the issue. At best, it will help the dealership understand the problem. At worst, it will be a good piece of evidence in a warranty dispute with Nissan.

MrB01112 said:

Well, I took my car to the dealership to have it looked at. I brought it into them with about 63% charge on it. They said they drove it around and were unable to duplicate the problem. I asked them if they took it up the highway and climbed the steep grade and they had not. They just drove it around town locally, couldn't find a problem and plugged it in when they brought it back. I told them that it only shows a problem on a steep grade going 65 mph, with a charge below 50%. They drove the car around to discharge it and then tried driving it up the hill with a 50% charge and were still unable to duplicate the problem.

They also hooked it up to there computer to analyze the state of the cells and were unable to see any issues. My gut feeling is that they probably won't see anything unless the battery is under extreme load.

In any case, I did get the Leafspy app and the OBDII sensor so I'm hoping that I might be able to keep that going the next time I get down below that 50% SOC so I might be able to record some data for them, and maybe get some video.

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Important to track correlation between "battery" temps (OAT means nothing, BTW...) and power available. On a long uphill climb, there should be ample evidence in the logs to show the issue. The logs are quite detailed and will also show each cell pair voltage. Yeah, its a lot to slog thru so tracking the Delta for large numbers will help to narrow down the issue if its a specific cell.

I have this issue too. 75 mph, heat on does it every time going up slight grade. E470 from Denver Airport to Parker. 5300’ to about 6000’ in 20 miles. I mentioned it to the service department at Boulder Nissan and they had never heard of it. A salesman overheard me and his 2019 does the same thing.
I bought a LeafSpy. When my %at 0 and miles at — LeafSpy said 26%. I continued fast and left the heat on this time and drove the last 20 miles home. The car had full power response the whole way. I got home with 11% on LeafSpy and still 0% on the car. My car is a 19 also.
With slower driving I’ve found LeafSpy and the car’s displayed % match pretty well till about 50%. Then they diverge until at 10% on car, LeafSpy shows 20%.

MrB01112 said:

They also hooked it up to there computer to analyze the state of the cells and were unable to see any issues. My gut feeling is that they probably won't see anything unless the battery is under extreme load.

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Take the car to am empty space at LBW with Leafspy running and showing the cell histogram. Press the brake firmly and then gradually press the GO pedal to the floor. LeafSpy lags real-time so expect to spend ~ 30 seconds on the test. I think you can record your phone screen as a video. You can also (and should) video the cars's SoC display.