2019 Leaf battery overheating

[OrientExpress]

I have a 2019 LEAF 40kWh for a week, and yesterday I did a test to see how the car would respond to a 7-hour continuous drive/quick charge regime.

I did three quick charges between 8 am and 3pm and drove the car at speeds between 65 and 85 on a flat section of freeway back and forth between two 50 kW quick chargers that are about 30 miles apart. The goal was to try to simulate a driving edge case scenario that a driver that has a Über, Lyft ride-share use or have an outside sales, delivery or service job might encounter.

The first quick charge of the morning ran at 35kW to about 65% capacity and then throttled down to 28kW until it finished at 92%, 45 minutes from start. An observation is that I have never had any LEAF, of any year, charge at more than 35kW at any of our local 50kW chargers.

I then topped it off on my home L2 to 100% which took about 45 minutes more. The temp gauge was to on the left side of the battery icon below the temp gauge when I started and dead center when I was done with the quick charge with 156 miles indicated. When I finished with the L2 top off the temp had gone back to the original starting temp and I was up to 167 miles.

Yesterday we had a weather front come through with heavy rain and strong winds of about 15 mph with gusts up to almost 30 mph. The winds started out as crosswinds on the road, and by the last run north had shifted into the north with about a 25mph headwind. Temps were in the 60 and 70's.

Because of the weather and the speed I was going, I got terrible economy (3.2 miles/kWh). By the time I had driven 85 miles, I was down to 22% capacity. Battery temp was now on the right edge of the temp gauge battery icon when I came in for the 2nd quick charge.

I had started the test about 11 am and came in for the 2nd quick charge with 22% left at 12:35. That charge started out at 32 kW, and ended at 24 kW. That brought the charge up toe 88% with the temp now up to about midway between the middle of the gauge and first red mark of the normal operating temp range.

Next came the most challenging part of the drive. The weather was in full force by then and I was driving north into a 30mph headwind, and was driving at about 75 mph with traffic. There were two isolated thunderstorms I drove through that did slow things down for a few miles.

About half way through this portion with 67% charge left, into strong headwinds, and driving at 75 mph, the temp had increased to about 3/4 of the space between mid range and the top end of the normal operating temp on the gauge.

I drove the car until it was down to 20% and pulled in for the third quick charge of the day at 2:31 pm. By then the temp was up to the first red mark on the temp gauge which was the top end of the normal operating temp.

For this third fast charge, the car started at 18kW and stayed there until the end of the charge session 45 minutes later. 18kW seems to be the floor for the '19 40kWh LEAF.

Here is an interesting thing that happened at about 20 minutes into the third quick charge, the battery temp dropped to about 3/4 between the mid point and the top point on the normal range on the gauge.

At the end of the third session. the range was up to 62% this time vs. 92% for the first quick charge and 88% for the second quick charge. At the end of the third charge the battery temp was back up to the first red mark on the temp gauge.

After about 30 minutes after completion of the 3rd quick charge the temp was back down to 3/4 between the mid point and the top point on the normal range on the gauge.

During the entire trip which in total was only 156 miles, the car performed completely normally, and if I hadn't been watching the temp gauge the entire time, I would have not been aware of the battery temp, which according to Nissan was operating the entire time in its normal temp range.

I would imagine that some would say that the 60-70 degree ambient temps that this test was conducted in do not represent what would happen in summer temps in Arizona, but the reports of 2019 40kWh LEAF owners operating in 90-100 degree weather seem to mirror my experiences. I do think that the temp gauge needs a bit of display updating as most people assume that if the gauge is to the red mark that is bad.

The nice thing is that the car will know if it enters a over-heat situation and will limit top speed and give the driver ample warning that it needs to cool down. It's sort of a "turtle-lite" mode that never happened on this test.

If you are interested in learning more about how this "turtle-lite" mode works you can read all about it on page 2-8 and 2-24 in the 2018 and 2019 LEAF owner's manual.

In comparison to my 2018 40kWh car, on the third Quick Charge it would have been charging at about 12 kW and lower, so clearly there are some changes in the charging profile on the 2019 car.

The goal of this test was to try to simulate the driving conditions of that 2-5% of 40 kWh LEAF drivers that use their cars for Über, Lyft ride-share use or have an outside sales, delivery or service job that require this sort of aggressive distance driving. While those situations are certainly the outliers of LEAF usage, they are certainly possible with a LEAF as long as the driver can accept the limitations of the cars charging management profile in those scenarios.

[SageBrush]

I have a 2019 LEAF 40kWh for a week, and yesterday I did a test to see how the car would respond to a 7-hour continuous drive/quick charge regime.

Don't you think it is time to get LeafSpy ? You have been a noob long enough.
Or does it interfere with your shill duties ?

[WetEV]

Or does it interfere with your shill duties ?

Check your Tesla stock today? Or did something else make you grumpy?

[OrientExpress]

Don't you think it is time to get LeafSpy ? You have been a noob long enough.
Or does it interfere with your shill duties ?

Nope, Until LEAF Spy can be certified by Nissan as being a credible measurement tool, it serves no purpose other than to entertain.

LEAF Spy is a perfect toy for experts such as yourself however.

[LeftieBiker]

I would imagine that some would say that the 60-70 degree ambient temps that this test was conducted in do not represent what would happen in summer temps in Arizona, but the reports of 2019 40kWh LEAF owners operating in 90-100 degree weather seem to mirror my experiences. I do think that the temp gauge needs a bit of display updating as most people assume that if the gauge is to the red mark that is bad.

First, you seem to have been trying to use "test" results from very mild weather to extrapolate to hot weather. Second, when the Leaf temp "gauge" is in the red it is definitely cause for worry. I don't know why you think otherwise, but please keep in mind that the Red zone of ANY temp gauge should be considered a definite warning. Manufacturers don't use red because they think it's pretty.

[SageBrush]

Don't you think it is time to get LeafSpy ? You have been a noob long enough.
Or does it interfere with your shill duties ?

Nope, Until LEAF Spy can be certified by Nissan as being a credible measurement tool, it serves no purpose other than to entertain.

If LeafSpy was doing something other than displaying the car's own canbus data you might have a point.

[OrientExpress]

First, you seem to have been trying to use "test" results from very mild weather to extrapolate to hot weather. Second, when the Leaf temp "gauge" is in the red it is definitely cause for worry. I don't know why you think otherwise, but please keep in mind that the Red zone of ANY temp gauge should be considered a definite warning. Manufacturers don't use red because they think it's pretty.

No, I am using the tests I conducted to extrapolate with different weather conditions simply because others have done essentially the same test in much hotter conditions in Arizona and come up with similar results. With the current LEAF batteries, elevated cold and hot environments are not as big of a factor as they were with pervious generations of the battery.

Now I do have expressed concerns with the HMI of the LEAF temperature gauge to those responsible for it, because there are lots of folks that come to the same conclusion that you have, based on their historical perceptions. Nissan's subtle approach using long and short blue and red marks to indicate operating range does not click with many of those that use preconceived notions and fail to RTFM. The Goldilocks area is between the short blue line and the short red line.

The other issue I've seen is that many people that come to your conclusion about what the gauge is describing is that they may not be familiar with a car that has automatic systems that protect the vehicle if there is a critical overheat (and underheat) situation by restricting the power available to the car until it is back within an acceptable operational temperature. Just about every BEV has a "turtle-lite" mode like the LEAFs that is designed to keep the vehicle's battery from being damaged. The car takes care of the situation that you are worried about so you don't have to.

As described in the owners manual the area between the short and long red mark is the warning area you are thinking of, and beyond the long red bar is where the automatic battery protection systems activate. The same goes for the short and long blue marks. In all the LEAFs I have driven over the years and all of the purposeful abuse I have laid on them, I have never had a situation where the temperature bar has gone beyond the first short red mark. Of course it does happen, and if one does get into that situation, the solution is to either drive slower, or stop for a while and let the battery cool a bit. I've found that the current battery can recover from being at the short red bar in 15-30 minutes by simply stopping or driving slower.

So again for the umpteenth time here is the section that describes that gauge. The key takeaway is that if the white bar on the gauge is between the short blue and short red mark, regardless where on the gauge it is, that is the normal operating temperature.

[OrientExpress]

If LeafSpy was doing something other than displaying the car's own canbus data you might have a point.

There is no visibility as to how LEAF Spy is interpreting, and in most cases what the CANBUS data it is reading and presenting actually means (sure the setting for doors and TPMS are easy to figure out). Lots of conjecture and made up units of measure, but with no certification, its got no value other than as an entertainment app.

I'm friends with the author of LEAF Spy, and he is great guy, but even he will admit the many of the readings presented are conjecture. In the end it's a hobbyist app for entertainment and shouldn't be taken too seriously.

[SageBrush]

If LeafSpy was doing something other than displaying the car's own canbus data you might have a point.

I'm friends with the author of LEAF Spy, and he is great guy, but even he will admit the many of the readings presented are conjecture.

While the important measurements are easily x-checked with "certified" alternative measurement systems or part of the published OBD spec.

[OrientExpress]

But yet in the 8-9 years of LEAF Spy's existence that has never been done. Perhaps you could contract to Jim to do that.