LeafSpy says I am good regarding imbalance after cell replacement?

[Newbie]

Hello everyone,

sorry I looked for an hour through the forum while not finding any answer, and the wiki as well as LeafSpyPro website seem to be offline as well:

After getting a cell replacement recently after getting the "Service EV system" error, a different forum member had posted that they got a 191mV value in LeafSpy so he had to go back to the dealership to have the imbalance addressed.

It took a few weeks but now I purchased the OBD dongle and the Leaf Spy Pro app (by the way, on my Samsung phones neither the Leaf Spy Lite nor Leaf Spy regular is available in the Google Play Store, only the $14.99 Pro version). Yesterday I finally got it connected and got the readings (see below):

since I only have a 23mV value (and not e.g. a 191mV value), that basically means I am all good after the battery replacement now, correct? The imbalance isn't too great, no need to take action?

Since my 36,000 factory warranty is going to run out soon, I just wanted to have this checked first.

Thank you all, for any help regarding this.

PS: Why does LeafSpy show "odo=22342mi" when in reality I am past 35,000 miles?

 

[knightmb]

Hello everyone,

sorry I looked for an hour through the forum while not finding any answer, and the wiki as well as LeafSpyPro website seem to be offline as well:

After getting a cell replacement recently after getting the "Service EV system" error, a different forum member had posted that they got a 191mV value in LeafSpy so he had to go back to the dealership to have the imbalance addressed.

It took a few weeks but now I purchased the OBD dongle and the Leaf Spy Pro app (by the way, on my Samsung phones neither the Leaf Spy Lite nor Leaf Spy regular is available in the Google Play Store, only the $14.99 Pro version). Yesterday I finally got it connected and got the readings (see below):

since I only have a 23mV value (and not e.g. a 191mV value), that basically means I am all good after the battery replacement now, correct? The imbalance isn't too great, no need to take action?

For replacement cells, that is actually just fine. The caveat is what the difference is at full charge and at nearly depleted states of the battery. At 100% charge, the cells should all be nearly identical. As you drive the Leaf and the battery depletes, that gap will open up, but it shouldn't be an issue as long as the gap isn't too wide the closer to 0% charge that you get. You would want to do an experiment of running it to nearly 0% with LeafSpy getting readings to see how wide the gap gets. It's also possible that you might be able to do a couple of full discharge and re-charge cycles to get the replace cells to line up very well with the old cells and might not even notice the gap or the gap may actually exceed the other cells and instead of it being lower like you see now, it could be higher all the time. Time will tell.

Since my 36,000 factory warranty is going to run out soon, I just wanted to have this checked first.

Thank you all, for any help regarding this.

PS: Why does LeafSpy show "odo=22342mi" when in reality I am past 35,000 miles?

There is a setting in LeafSpy to read the CAN bus mileage version I think? I can't remember exactly what it was called, but it will fix the wrong mileage issue.

 

[Newbie]

For replacement cells, that is actually just fine. The caveat is what the difference is at full charge and at nearly depleted states of the battery. At 100% charge, the cells should all be nearly identical. As you drive the Leaf and the battery depletes, that gap will open up, but it shouldn't be an issue as long as the gap isn't too wide the closer to 0% charge that you get. You would want to do an experiment of running it to nearly 0% with LeafSpy getting readings to see how wide the gap gets. It's also possible that you might be able to do a couple of full discharge and re-charge cycles to get the replace cells to line up very well with the old cells and might not even notice the gap or the gap may actually exceed the other cells and instead of it being lower like you see now, it could be higher all the time. Time will tell.

This is great - such a quick and helpful reply is very much appreciated!

Since the replacement was done in January and now we have March, I already went through a few discharge and re-charge cycles. But I only got by OBD dongle/Leaf Spy Pro yesterday.

Obviously I took that reading that I posted the screenshot of, at nearly 100% charge.
So now I plan to see what the readings my be like e.g. when it is half full, or when it is nearly empty.
What would be acceptable or unacceptable levels e.g. when nearly at 0%? E.g. would above 50mV be a reason to bring it to the dealer to fix it? As I wasn't able to access any guide on the LeafSkyPro website or the wiki appears to be down, I am not sure how to interpret the values displayed or in which situations one actually needs to take action to have the dealer correct anything.

I plan to drive this Leaf for many years still and thus don't want to have an unnecessarily lower range, due to imbalance. Because the battery will degrade anyway over the years and thus range will get lower because of that, but I did not want to get an extra lower range due to imbalance. So I just wanted to look into it to be sure all is okay prior to the warranty expiring.

Thank you everyone for all your help.

 

[knightmb]

Obviously I took that reading that I posted the screenshot of, at nearly 100% charge.
So now I plan to see what the readings my be like e.g. when it is half full, or when it is nearly empty.
What would be acceptable or unacceptable levels e.g. when nearly at 0%? E.g. would above 50mV be a reason to bring it to the dealer to fix it? As I wasn't able to access any guide on the LeafSkyPro website or the wiki appears to be down, I am not sure how to interpret the values displayed or in which situations one actually needs to take action to have the dealer correct anything.

When it comes to hoping for the best, you would want that gap to remain small at 100% and slowly widen near 0%, but even the best balanced brand new battery pack is going into get a bit disorganized the closer to 0% that you get. I'm sure others will chime in on this discussion of what they think is a "bad" spread, but it comes down to getting the most range possible. The Leaf is calculating your range based on the power measurements (power in and power out) and the voltage of the "worst" cell when the battery is near depletion. It's possible that some others cells in your pack will be much lower voltage when you get to 0%, you just won't know until you try.

The advantage of having everything "close" is that you will get the most possible range before shutdown. What is kind of an open secret among Leaf owners with the 62 kWh battery is that there is a "hidden" reserve at 0% on the dash. You can only see it with LeafSpy, but it's possible to get up to almost another +30 miles of range at 0% if you drive gently enough and the voltage balance of your pack can remain close all the way to shutdown voltage.

This also exist on the 40 kWh packs, but at half the "hidden" reserve to around 15 miles with optimal conditions. The only reason I know that is this experiments I do on my own and my wife's Leaf. :lol:
Hidden Reserve - What is hiding in your 24, 30, 40, 62 kWh Battery? https://mynissanleaf.com/viewtopic.php?t=32148

I plan to drive this Leaf for many years still and thus don't want to have an unnecessarily lower range, due to imbalance. Because the battery will degrade anyway over the years and thus range will get lower because of that, but I did not want to get an extra lower range due to imbalance. So I just wanted to look into it to be sure all is okay prior to the warranty expiring.

Thank you everyone for all your help.

Good idea, you have a lot of support for that here.

 

[Newbie]

When it comes to hoping for the best, you would want that gap to remain small at 100% and slowly widen near 0%, but even the best balanced brand new battery pack is going into get a bit disorganized the closer to 0% that you get. I'm sure others will chime in on this discussion of what they think is a "bad" spread, but it comes down to getting the most range possible. The Leaf is calculating your range based on the power measurements (power in and power out) and the voltage of the "worst" cell when the battery is near depletion. It's possible that some others cells in your pack will be much lower voltage when you get to 0%, you just won't know until you try.

The advantage of having everything "close" is that you will get the most possible range before shutdown. What is kind of an open secret among Leaf owners with the 62 kWh battery is that there is a "hidden" reserve at 0% on the dash. You can only see it with LeafSpy, but it's possible to get up to almost another +30 miles of range at 0% if you drive gently enough and the voltage balance of your pack can remain close all the way to shutdown voltage.

This also exist on the 40 kWh packs, but at half the "hidden" reserve to around 15 miles with optimal conditions. The only reason I know that is this experiments I do on my own and my wife's Leaf. :lol:
Hidden Reserve - What is hiding in your 24, 30, 40, 62 kWh Battery? https://mynissanleaf.com/viewtopic.php?t=32148

[...]

Good idea, you have a lot of support for that here.

Thank you so much for sharing this.

Regarding the extra reserve at 0%, I was aware of it - thank you for all the testing you did regarding that. Now with LeafSpy, I can even see myself how the dashboard says 11% but LeafSpy says 19%, so it appears like it is obvious how the dashboard readings are different.

Back to my main point, I wasn't able to get the battery all the way to 0%, but I got the charge level to come down at least quite a bit to 19%. So here is what it looks like at 19%, LeafSpy says the 61mV is the spread, due to the replaced module. Isn't this very high? What would be the best thing that I could ask the dealership now to do, do remedy this?

Below I am sharing the screenshot from LeafSpy.

 

[knightmb]

Thank you so much for sharing this.

Regarding the extra reserve at 0%, I was aware of it - thank you for all the testing you did regarding that. Now with LeafSpy, I can even see myself how the dashboard says 11% but LeafSpy says 19%, so it appears like it is obvious how the dashboard readings are different.

Back to my main point, I wasn't able to get the battery all the way to 0%, but I got the charge level to come down at least quite a bit to 19%. So here is what it looks like at 19%, LeafSpy says the 61mV is the spread, due to the replaced module. Isn't this very high? What would be the best thing that I could ask the dealership now to do, do remedy this?

Below I am sharing the screenshot from LeafSpy.

Here is the interesting part, the screen-shot from before showed those "replaced" cells seeming to lag behind the others, but now that you have a depleted battery screen-shot, you'll notice that the same group of replaced cells are now "higher" than all the others.

I suspect this is happening because the replaced cells are either newer or are in better condition. That means you would want to pay more attention to the other cells around them.

Going by the screen-shot at 19%, there is still room left to better balance out the "old" cells but that large "gap" you see is nothing to worry about because it's showing the "newer" cells versus the "older" cells at this point to give you a false sense of danger.

If you mentally exclude those "higher" cell groups and compare the next highest to the lowers, the voltage spread doesn't look bad at all.

Could they be better balanced? Sure if you have the time and resources to do it.

Will it affect range? Maybe once you get the battery down to a really low %, then the weakest cell is going to dictate how much "range" you can squeeze from the bottom end.

Overall, your replacement cells have more capacity than your original, so it's going to kind of "skew" readings along the way. The dealership will not be able to do anything about this. You can though, if you have the time and patience to try a few things.