I drove from North Carolina to Ohio yesterday (400 mi total trip) and after the 3rd charge, the battery temp gauge was in the unhappy range (one segment of red was showing), although I did not get any warnings on the dash about it. What happens when it gets "too hot"? I am assuming Nissan has tested this and it will turn off before Very Bad Things happen, but has anyone experienced/heard stories about the car saying it's going to turn off due to overheating?
What happens when the battery "overheats"?
- Thread starter cgtyoder
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Stanton
Well-known member
Battery damage due to over-heating is a lot like blood pressure for us: while the immediate affects may not be noticeable, there is probably long-term damage (cell degradation). I recommend caution when any battery pack (phone/laptop/etc) becomes over-heated--especially when there is no active cooling (like in a Leaf). For example, I try not to charge when the pack is hot (e.g. 7 TB in a Gen1 Leaf). I think motor power can become limited in extreme heat conditions, but if you're at that point, then you probably don't care about long-term affects anyway.
I actually do care about long-term effects - I care about being able to get home as well 
What do you mean by "7 TB"? I am not familiar with that lingo. I would hope the car would give me plenty of warning if things were truly dangerous/damaging. I knew this was going to be an adventure - we shall see how the journey goes...
What do you mean by "7 TB"? I am not familiar with that lingo. I would hope the car would give me plenty of warning if things were truly dangerous/damaging. I knew this was going to be an adventure - we shall see how the journey goes...Learjet
Well-known member
I'm guessing the meaning is 7 temperature bars?...not sure how to count them on the newer cars.
The latest generation Leaf has the same number of temperature bars as the early cars, but the line segments aren't delineated, so they look like an unbroken graph. If the battery goes into the 'Red Zone' but not all the way through it, that isn't likely to cause a breakdown or substantial damage to the battery. Is this what happened to you? If so, then just try to avoid having it happen often.
LeftieBiker,
Yes, that was exactly the case - the battery temp meter went partially into the Red Zone. Looks like the Leaf is not up for long trips (moving quickly) in the summer, so I guess the other car in the household gets used for that case!
Yes, that was exactly the case - the battery temp meter went partially into the Red Zone. Looks like the Leaf is not up for long trips (moving quickly) in the summer, so I guess the other car in the household gets used for that case!
The blood pressure analogy in an earlier post is good. The first red mark on the temperature display is equivalent to 10 bars on the older car displays; second red mark is 11 bars; end of scale is 12 bars; and center of scale is 6 bars. The controllers in the car will limit maximum motor power and regeneration when the battery temperature gets farther into the red zone. The power limit is progressive so acceleration will be reduced as temperature increases. There is still enough power to maintain highway speed on the level at 11 bars, but acceleration will be limited and speed may drop going up hill. If battery temperature continues to increase, the controllers will eventually engage turtle mode (severe power limited mode with turtle symbol on dash) and speed will drop to around 25 mi/hr (happened to me once with 2011 after highway driving and DCQC followed by city driving caused battery temperature to reach 12 bars). Of course, the controllers will also limit DCQC charge rate as battery temperature increases even below the red zone.
My battery temperatures have been either 8 or 9 bars the last few days without highway driving or DCQC. It has been 10 bars with more driving in a single day, but dropped to 9 bars during overnight charging. I think the maximum I have ever seen on the 2019 has been 11 bars.
My battery temperatures have been either 8 or 9 bars the last few days without highway driving or DCQC. It has been 10 bars with more driving in a single day, but dropped to 9 bars during overnight charging. I think the maximum I have ever seen on the 2019 has been 11 bars.
OrientExpress
Well-known member
Here is an article that talks about the BMS from a few years ago. Scroll down to the part of the article "Under the hood and under the floor":
https://insideevs.com/reviews/354688/2019-nissan-leaf-40-kwh-test-drive/
https://insideevs.com/reviews/354688/2019-nissan-leaf-40-kwh-test-drive/
Stanton
Well-known member
That's exactly the conclusion you should walk away from this thread with. EVs with some sort of active cooling would be preferred to a Leaf (that has no TMS) on "road trips". I use my Leaf "around town", but my wife's ICE car for "road trips".cgtyoder said:
DougWantsALeaf
Well-known member
In my daily trips over 550 miles in our Plus, I find that if the temps is under 70, the battery will slowly cool during efficient highway driving (say around 4 miles/kWh), between 120F+ down to about low 100s. If it's hotter, minimal cooling between stops. Above 85, and you get almost no cooling while driving.
At 100F you can get most of a charge (20-90%) at a 50KW charger without much throttling. The 200amp/100KW chargers will start faster but throttle by half charge.
If it's below 40F you cool faster, but the power draw increases due to wind resistance and potential chilly occupants.
40-65F is the sweet spot for the Leaf over 400 miles.
At 100F you can get most of a charge (20-90%) at a 50KW charger without much throttling. The 200amp/100KW chargers will start faster but throttle by half charge.
If it's below 40F you cool faster, but the power draw increases due to wind resistance and potential chilly occupants.
40-65F is the sweet spot for the Leaf over 400 miles.
cwerdna
Well-known member
OP can skip around in https://www.youtube.com/watch?v=guEyn0va_cE to see what happens to his charge speed eventually.
https://www.youtube.com/watch?v=Ps8hwnxzk4c is better.
1000 km is ~621 miles.
Dala at https://www.mynissanleaf.com/viewtopic.php?p=590000#p590000 shows what happens in extreme cases of 30 and 40 kWh Leafs being used for taxi duty w/multiple DC FCs a day. The rear stack degrades more than the rest cuz it heats up more and in really bad cases, you can see the rear modules swell and are trashed. See 3:30 into the video. There have been other documented cases of that.
https://www.youtube.com/watch?v=Ps8hwnxzk4c is better.
1000 km is ~621 miles.
Dala at https://www.mynissanleaf.com/viewtopic.php?p=590000#p590000 shows what happens in extreme cases of 30 and 40 kWh Leafs being used for taxi duty w/multiple DC FCs a day. The rear stack degrades more than the rest cuz it heats up more and in really bad cases, you can see the rear modules swell and are trashed. See 3:30 into the video. There have been other documented cases of that.
cwerdna
Well-known member
https://www.plugshare.com/location/5485 claims to be above 50 kW. Ditto for https://www.plugshare.com/location/465058.
Sometimes, EA lifts the 50 kW cap on their "50 kW" CHAdeMO handles like at https://insideevs.com/news/495913/nissan-leaf-dc-fast-charging-curve/.
Sometimes, EA lifts the 50 kW cap on their "50 kW" CHAdeMO handles like at https://insideevs.com/news/495913/nissan-leaf-dc-fast-charging-curve/.
DougWantsALeaf
Well-known member
cgtyoder said:
I can get upper 70s from many newer evgo stations. The newer Chargepoint and Shell stations generally will give me 60-70 to start if battery is 4-7 temp bars and under 30% SoC.
80KW is the highest I have seen from a Leaf in the wild.
BillAinCT
Well-known member
There are 2 sites with 4 CHAdeMO 100kW each in MA near I90 at I84 and east of Worcester and 6 in Nanuet NY near I287. Charging for 25 minutes to get 60-65% is nice. I don't need 2+ FC's in my travels.
