Battery 17% sudden drop while driving

[Chad E. Mo]

The LeafSpy Pro app and the suggested OBD dongle are essential for DIY Leaf troubleshooting, and cost less than a decent socket wrench.

With the release of version 0.39.97 LeafSpy Pro now supports two Bluetooth 4.x LE approved adapters. The recommended one is the LELink available from Amazon. Bluetooth 4.x LE has the advantage of not needing to be paired and lower power from both the Android device and the Leaf. The LELink is highly recommended and also works with the iOS version of LeafSpy Pro.

https://play.google.com/store/apps/details?id=com.Turbo3.Leaf_Spy_Pro

 

[Stanton]

Does anyone have a specific OBDII dongle that has worked with the LEAF and LeafSpy? There are so many super cheap to quite expensive; some require their app to be downloaded, etc.

Here's a good tutorial on choosing an OBDII dongle for LeafSpy (Choosing OBDII adapter – Car Scanner ELM OBD2).
I use a VGate iCar dongle I bought off Amazon.

 

[MikeDenn]

Sorry to be thick but where is the socket located to plug the OBDII dongle in on a 2020 leaf?

 

[user546379]

UPDATE: The problem has gotten worse since my original post. The GOM will rapidly drop by more than 40 percentage points over the distance of just 4 to 5 miles. So it seems unlikely that is is related to the software update that was done. There was a recall just announced that applies to my car, as described in this newer thread:
https://mynissanleaf.com/threads/recall-r24b2-battery-state-of-charge.36460/page-2#post-651050

 

[nlspace]

UPDATE: The problem has gotten worse since my original post.

Did you get an OBDLInk LX dongle and use the LaefSpy app to monitor what is happening while you are driving up that big hill at 60-65 mph?

The cells will sag under high load--that's just how batteries work. It would be a problem and an issue if there were one or more modules that were way out of family (excessive sag) with all the rest, and if it got dragged low enough it would trigger the Turtle mode.

When the hill is crested the load is lessened, and the cells have a chance to recover (the SOC% rebound)--that's just how batteries work.

If you want to know if you have a problem then you need to monitor the cell and pack voltage along with the power and current draw when all this mess is happening.

What is the grade of the hill and the length of the drive up? Try running it at 50 mph and at 70 mph to see some different results for comparison.

It might be related to a software issue, but maybe LS can help you to rule out any hardware concerns first.

Good luck and hope you can get to the bottom of this.

 

[Jerther]

Your problem should be covered by the traction battery warranty. Has your dealer agreed to investigate? If not, find another one. In any case, they have to replicate your problem first. Videos and pictures are not enough, but could help them replicate the problem. Also, it should be more severe and obvious in colder weather. I have written quite a bit about the process as I went through this two times

https://mynissanleaf.com/threads/rapid-charge-loss.27994/page-3#post-635081
https://mynissanleaf.com/threads/2018-getting-a-new-battery-under-warranty-now-what.34795/
https://mynissanleaf.com/threads/new-40kwh-battery-on-2018-sl-sudden-charge-drop-at-low-load.34917/

 

[Stephen Manning]

Hi fellow Leafers!

I have recently noticed something similar with my Jan-2020-reg 39kW Leaf, my first EV which I've had close to 2 years. I make a regular evening journey of 16 miles out (nett downhill), a 2-hour stop then the same route back (nett uphill). The typical cost of this is ~7% out plus ~14% back, rising to ~30% total in winter.

A couple of weeks ago the weather here (northern England) was 0C and dry, and I set off with 77% charge and arrived with 63%. Halfway back it showed 43% as I started to accelerate to 50 mph for a two-and-a-half-mile gradual climb, and before I reached the top it had plummeted to around 15%, recovering to ~30% as I eased off over the brow. On arrival at home it showed 15%. Charging to 100% at home took 22.2 kWh, which suggests that the real SoC was around 40% ish.

The same journey a week later, with temperature +3C and dry, and a starting SoC of 92%, got me there on 80% and back home on 60%, which looks reasonable. This backs up other posts which suggest the problem occurs at low temperatures with SoC below around 50%.

Is there an "official" report on what's going on here, or do we rely on the user community? I have had a more worrying incident on a similar journey, where I encountered 5% and a "Charge NOW!!!" warning 4 miles from home, even though there was ~30% still in the battery.

Thanks guys.

This sounds like my experience...I was my driving 40kwh leaf fast and it was cold. The charge suddenly dropped, I got a warning light, I eased off the speed, the warning light extinguished and the charge % figure climbed back to 50%

 

[Bombastinator2]

This sounds like my experience...I was my driving 40kwh leaf fast and it was cold. The charge suddenly dropped, I got a warning light, I eased off the speed, the warning light extinguished and the charge % figure climbed back to 50%

Were you on the highway? The electronics might have gotten buggered by the cold. It’s a known problem. I’ve considered trying stuffing a bit of rock wool in there but it only came up once. If it happens again I will try it and report back.

 

[cornbinder89]

Actual temp matters here. Cold to some is 20 deg F, cold to me is -20 deg F.
I experienced similar loss and return at -17 deg F and it has never shown up again.
As the temp drops all batteries loose some ability to provide current, In the case of the Leaf, if the motor draw "request" is more than the battery can supply the cell voltage drops rapidly, the electronics sense this and report a drop in range, When the load goes back to what the battery can supply at that temp, the range reported comes back.
Whether it is "normal" depends on temp and power requested.
at -17 F a high power hill climb, I expect to trigger this warning, I do not expect to see it at +20 F.
Monitoring the cell voltage in Leafspy while driving up a hill in the "cold" will show what is happening when.

 

[Bombastinator2]

Actual temp matters here. Cold to some is 20 deg F, cold to me is -20 deg F.
I experienced similar loss and return at -17 deg F and it has never shown up again.
As the temp drops all batteries loose some ability to provide current, In the case of the Leaf, if the motor draw "request" is more than the battery can supply the cell voltage drops rapidly, the electronics sense this and report a drop in range, When the load goes back to what the battery can supply at that temp, the range reported comes back.
Whether it is "normal" depends on temp and power requested.
at -17 F a high power hill climb, I expect to trigger this warning, I do not expect to see it at +20 F.
Monitoring the cell voltage in Leafspy while driving up a hill in the "cold" will show what is happening when.

I was told there is a component under the car that is air cooled and if it gets too much air cooling, as can happen on the highway in, lets call them really cold, temps it happens. Might be that though. Or we might actually be saying the same thing but don’t know it. You’re apparently saying it’s the battery itself rather than a battery controller. Both would be under the car though. Would mean a lot more rockwool. If it’s the battery itself what about hinged slats designed to be blown flat by moving air. When the car is stopped, or even slow, they fall open. Or what are effectively mini blinds under the battery. Closed they prevent air circulation, open the don’t.

 

[Bombastinator2]

The LeafSpy Pro app and the suggested OBD dongle are essential for DIY Leaf troubleshooting, and cost less than a decent socket wrench.



https://play.google.com/store/apps/details?id=com.Turbo3.Leaf_Spy_Pro

*searches yet again for an “I agree” emoji*

 

[chk]

This is quite normal if your battery has a low Hx (<85%, see Leaf Spy results) or it's very cold and you drag a lot of energy - the BMS notices there is less energy coming from the battery pack due to high inner resitance in the cells and it reduces the estimation until the power consumption is reduced.

There is a thread somewhere here with a viseo showing this effect.

It's a bit early for a 2020 Leaf though.

 

[LeafDriver21]

Hello All-
I am new to the forum and have a 2020 Leaf with 52K miles on it and lowest range ( i guess that means lowest power battery) but had similar battery % drops others are describing after my battery reached about 55% (45% used). I took it to the dealer and they diagnosed it as having a faulty module. The have had the car 3 months! and I have been driving a loaner for three months. My questions is how will the car perform when I get it back and what can I expect in the future? Does failure of one module affect the other modules-- ie does it weaken them?? Any info would be helpful.
I don't erven know what LeafSpy is-- I'll have to look it up!

 

[cornbinder89]

The battery can only preform to the capacity of the weakest cell. so when the replace the weak cell(s) the battery should be fine.