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Discussion Starter #1
Hi.. I am from Sri Lanka. Currently i have 3white bars & 2Red bars in my car. It is 2014 (Japan) manufacture and run almost 140,000KM now. After 100% full charge i usually drive around 50-60KM with A/C. What i want to know is, "replacing the battery cell" is good or not?. How success is it at all and is it worthy to do ? and finally if replaced the cell then how far it can be use and how many KM’s can run with it. I would like to know your idea and recommendation on this.

Also recently i found my Ahr & SOH dropping so quick. I have attached here some screenshots.

Any idea & Help ?
 

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Replacing cells is normally something that is done when there are only a few weak cells rather than so many as in your pack. I have never seen so many cells degraded so far, and presume that it's your hot weather that is the issue.
If it were me I'd look to replace the whole pack but the economics may be different in your country.
 

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Replacing cells is normally something that is done when there are only a few weak cells rather than so many as in your pack. I have never seen so many cells degraded so far, and presume that it's your hot weather that is the issue.
If it were me I'd look to replace the whole pack but the economics may be different in your country.
Do you think battery calibration will help for this ?, Somebody told me battery calibration will be good for this situation.
 

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I would call that battery end of life. It's been quick charged over 1,600 times.

If you get the charge level down very low and run leafspy again it will do a CVLI test and report at the bottom of the screen "All cells ok" or "Weak Cells" along with their numbers.

If you get "All cells ok" then you need a whole new pack to restore any range, they are worn equally.
If you get "Weak cells" then you could replace those individual modules and see some improvement, but only up to the level of the next weakest cell. If there's one really defective module this can be worth it, but generally not the case.
 

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Sorry to sound like I'm talking down to you, but you understand that the battery pack is made up of modules of cells? Each module is shown separately on LEAFSpy, and the BMS works on them in pairs. You cannot "calibrate" the battery as such - the BMS does its best within the limitations of the cell pairs. What can be done, BUT I AM NOT RECOMMENDING IT, is to split the case of the battery and access the individual cells. If you charge individual cells it is possible to get the voltages closer at the bottom end of their voltage range and hence delay the advent of the Turtle appearing (which is based on the lowest voltage of any cell).
You have not included a LEAFSpy image of the battery at present when it is fully (or as near as you ever get to fully) discharged. But if you imagine that this image you posted on the pack charged was it discharged:


If you look at module pairs 77/78 on the x-axis they are considerably lower than the others. If this was a discharged image then it is that pair that will cause the Turtle to appear first or just your GOM to indicate no range left. In theory charging just those cells up to the level of the others would increase the range of the pack as the other cells have further to go to reach the limit.
In practice there are many issues:
  • Splitting the pack means working with very high voltage and danger of death.
  • The modules are likely to be genuinely weak and will likely return to their lower readings quite quickly
  • If they are weak they are likely to charge at a different rate limiting the full charge potential
You could replace one or more modules, but without a discharged image from LEAFSpy it is impossible to tell how many are required. My guess, and it is no more than that, is that it is more than 10 (most of the rear ones) and that a different battery pack secondhand from a cool climate such as the UK would be a more cost effective idea, although you are then into issues regarding reprogramming the car to accept the different pack.

So the next action has to be to run the battery as empty as you dare then get another LEAFSpy image and post it here. Good luck!
 

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Discussion Starter #6
Sorry to sound like I'm talking down to you, but you understand that the battery pack is made up of modules of cells? Each module is shown separately on LEAFSpy, and the BMS works on them in pairs. You cannot "calibrate" the battery as such - the BMS does its best within the limitations of the cell pairs. What can be done, BUT I AM NOT RECOMMENDING IT, is to split the case of the battery and access the individual cells. If you charge individual cells it is possible to get the voltages closer at the bottom end of their voltage range and hence delay the advent of the Turtle appearing (which is based on the lowest voltage of any cell).
You have not included a LEAFSpy image of the battery at present when it is fully (or as near as you ever get to fully) discharged. But if you imagine that this image you posted on the pack charged was it discharged:


If you look at module pairs 77/78 on the x-axis they are considerably lower than the others. If this was a discharged image then it is that pair that will cause the Turtle to appear first or just your GOM to indicate no range left. In theory charging just those cells up to the level of the others would increase the range of the pack as the other cells have further to go to reach the limit.
In practice there are many issues:
  • Splitting the pack means working with very high voltage and danger of death.
  • The modules are likely to be genuinely weak and will likely return to their lower readings quite quickly
  • If they are weak they are likely to charge at a different rate limiting the full charge potential
You could replace one or more modules, but without a discharged image from LEAFSpy it is impossible to tell how many are required. My guess, and it is no more than that, is that it is more than 10 (most of the rear ones) and that a different battery pack secondhand from a cool climate such as the UK would be a more cost effective idea, although you are then into issues regarding reprogramming the car to accept the different pack.

So the next action has to be to run the battery as empty as you dare then get another LEAFSpy image and post it here. Good luck!

This will be helpful for you to give me some more information?,



130843



130844
 

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Discussion Starter #7
I would call that battery end of life. It's been quick charged over 1,600 times.

If you get the charge level down very low and run leafspy again it will do a CVLI test and report at the bottom of the screen "All cells ok" or "Weak Cells" along with their numbers.

If you get "All cells ok" then you need a whole new pack to restore any range, they are worn equally.
If you get "Weak cells" then you could replace those individual modules and see some improvement, but only up to the level of the next weakest cell. If there's one really defective module this can be worth it, but generally not the case.
130845


130846
 

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If you get "Weak cells" then you could replace those individual modules and see some improvement, but only up to the level of the next weakest cell. If there's one really defective module this can be worth it, but generally not the case.
Ouch!
Clearly there is bad, and there is awful. I'd argue that the majority of modules between 60 and 86 are in a bad way and would ideally be swapped, rather than the 4 pairs that LEAFSpy has identified of 65(66), 67(68), 77/78, 79/80.
New battery time in my opinion if the rest of the car justifies the expense.
 

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Discussion Starter #9
Ouch!
Clearly there is bad, and there is awful. I'd argue that the majority of modules between 60 and 86 are in a bad way and would ideally be swapped, rather than the 4 pairs that LEAFSpy has identified of 65(66), 67(68), 77/78, 79/80.
New battery time in my opinion if the rest of the car justifies the expense.

Ohh sadness.. can't help if replace 65(66), 67(68), 77/78, 79/80 cells ? .. hmm coz at the moment thinking of a new battery is bit hard for me.
 

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I appreciate the cost - not a small amount.
You have a similar number of other cells within 50mV of those, and more if you go to 50mV from the remainder of the pack. If you "just" change the 8 you may as well change the other 18, and then you are close in component prices to a good secondhand pack but with all the cells degraded significantly.
If going for a good secondhand pack go for a 30kW one, they take the heat better not to mention have greater capacity in the first place.
 

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Discussion Starter #11
Hi Brothers,

Recently i have calibrate the battery and now i am getting this result.I like to know what about your ideas and thinking bros.

131107
131108
131109
 

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How did you “calibrate” them? My feeling would be that new ah reading is false and if you run the car low you’re going to get an unexpected turtle and stop.
 
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