Cells replaced, how to update SoH & Ahr

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xafalcon

Well-known member
Joined
Jan 23, 2020
Messages
57
I have replaced the cells in my 2013 AZEO leaf with much lower milage cells from a 2015. Is there a process to update the SoH & Ahr that doesn't involve a consult 3 tool?

Thanks in advance for any help
 
I am not 100% certain, but I believe that all you have to do is reset the BMS and it will re-learn the battery stats. I know that it is possible to do this without the Consult tool, but the exact procedure hasn't AFAIK, been posted. I assume that it involves disconnecting the BMS from power for a while, but again, I don't know the exact procedure. There is at least one third party app that claims to be able to change the SOH, but aside from ethical issues I don't know if it's still available.
 
Thanks for the replies. I know of the 3rd party app you speak of, but not a route I want to take. Dealing in Roubles isn't my cup of tea

I thought there may have been a simpler process to force the lbc to learn more quickly

I tried many combinations of full fast charging, running the battery as low as I dared, multiple slow charge to full to allow balancing, but nothing seemed to work

Then one day the SoH jumped up by 0.3%. But at this rate, it will take several years (or maybe the degradation of the New cells will drop faster than the SoH and Ahrs increase!!)

Hopefully someone can give me some guidance

Thanks again
 
Sounds like a call for Dala the Great is in order--he is the master of replacing packs.
 
If it's just for your own use, why do you care about the SOH? Unless the BMS is artificially limiting your range, then the SOH is irrelevant. Eventually it will reflect the true capacity, until then just enjoy the extra range.
 
nlspace said:
Sounds like a call for Dala the Great is in order--he is the master of replacing packs.

Dala the Great took a new job, so I suspect he won't be spending countless hours hacking the LEAF anymore:

https://www.youtube.com/watch?v=louSGsibOjk
 
Nice! I really wish Dala well in his new job. He's always been a champion of our Leafs and willing to share his findings for all to learn from. It will be interesting to see how his CSS to CHAdeMO conversion project goes, sounds like an interesting approach.
 
alozzy said:
If it's just for your own use, why do you care about the SOH? Unless the BMS is artificially limiting your range, then the SOH is irrelevant. Eventually it will reflect the true capacity, until then just enjoy the extra range.

The car does not appear to have gained any significant range. But going from 60% to 75% SoH should yield a 25% range increase. The "fuel gauge" depletes approximately as quickly as it used to. It makes no sense to me

I'm wondering if the lbc is limiting the amount of charge it accepts?? But cell voltage rises to the usual 4.12 volts so this does seem to fit??
 
xafalcon said:
alozzy said:
If it's just for your own use, why do you care about the SOH? Unless the BMS is artificially limiting your range, then the SOH is irrelevant. Eventually it will reflect the true capacity, until then just enjoy the extra range.

The car does not appear to have gained any significant range. But going from 60% to 75% SoH should yield a 25% range increase. The "fuel gauge" depletes approximately as quickly as it used to. It makes no sense to me

I'm wondering if the lbc is limiting the amount of charge it accepts?? But cell voltage rises to the usual 4.12 volts so this does seem to fit??

Until you do a manual battery calibration, it won't *seem* to have much more range. The computer has learn about the extra range and the only way I've seen it possible without software is manually running the battery down and then slowly running out the rest of the battery until shutdown so the computer can learn what the true capacity of the battery pack is.
 
xafalcon said:
alozzy said:
If it's just for your own use, why do you care about the SOH? Unless the BMS is artificially limiting your range, then the SOH is irrelevant. Eventually it will reflect the true capacity, until then just enjoy the extra range.

The car does not appear to have gained any significant range. But going from 60% to 75% SoH should yield a 25% range increase. The "fuel gauge" depletes approximately as quickly as it used to. It makes no sense to me

I'm wondering if the lbc is limiting the amount of charge it accepts?? But cell voltage rises to the usual 4.12 volts so this does seem to fit??

I might be wrong, but I would think that the range is dictated by when the BMS senses that the lowest voltage cell hits the cutoff voltage. So, the dash SOC would show --- but there should still be additional capacity (assuming the "new" cells you added are better than the worst cells that they replaced). That's how it would work on an eBike battery, but I'm not sure about the LEAF BMS...
 
Thanks everyone. Sounds like I need to run the traction battery down until it goes into the turtle mode. Then fully charge it. The current sensor in the battery pack will then know how much energy has gone in.

If anyone else has a different idea, please let me know

Thanks
 
xafalcon said:
alozzy said:
If it's just for your own use, why do you care about the SOH? Unless the BMS is artificially limiting your range, then the SOH is irrelevant. Eventually it will reflect the true capacity, until then just enjoy the extra range.

The car does not appear to have gained any significant range. But going from 60% to 75% SoH should yield a 25% range increase. The "fuel gauge" depletes approximately as quickly as it used to. It makes no sense to me

I'm wondering if the lbc is limiting the amount of charge it accepts?? But cell voltage rises to the usual 4.12 volts so this does seem to fit??

If you replaced "all" the cells with better ones, this does not mean the BMS will recognize this. But the car runs so that is significant, right? It is the BMS that controls what access you have to the pack. It is this you must get onboard with.

As far as your "gain 15% SOH equates to 25% increase in range" statement? Need a LOT more clarification on how you came about that math. The other thing to consider is SOH is not a statement of capacity, ahr is.

If I am not mistaken, the BMS reset is a relatively simple matter of jumping a few contacts but that is just a vague memory and I have no idea how to go about it. If the range is that important, I would suggest getting the bridge device and honoring the work of the people before you.
 
Yes, it's the lbc that I need to re-learn so that I can just drive it to the full capacity without worry about running out as I drive it "into the red"

Original battery SoH was 60%, replacement modules came from a 75% SoH battery. 60% x 125% = 75%. Ie a 25% increase. SoH and Ahr are roughly measures of the same thing, they move in tandem as the battery cycles increase

My preference is not to reset the lbc, as that could cause the opposite problem - an overestimate of remaining battery capacity. Leaving me stranded on the side of the road

My preference is to speed up the natural "capacity learning" of the lbc

But if the later is not possible, then the former may be the only option




If you replaced "all" the cells with better ones, this does not mean the BMS will recognize this. But the car runs so that is significant, right? It is the BMS that controls what access you have to the pack. It is this you must get onboard with.

As far as your "gain 15% SOH equates to 25% increase in range" statement? Need a LOT more clarification on how you came about that math. The other thing to consider is SOH is not a statement of capacity, ahr is.

If I am not mistaken, the BMS reset is a relatively simple matter of jumping a few contacts but that is just a vague memory and I have no idea how to go about it. If the range is that important, I would suggest getting the bridge device and honoring the work of the people before you.
[/quote]
 
xafalcon said:
Yes, it's the lbc that I need to re-learn so that I can just drive it to the full capacity without worry about running out as I drive it "into the red"

Original battery SoH was 60%, replacement modules came from a 75% SoH battery. 60% x 125% = 75%. Ie a 25% increase. SoH and Ahr are roughly measures of the same thing, they move in tandem as the battery cycles increase

My preference is not to reset the lbc, as that could cause the opposite problem - an overestimate of remaining battery capacity. Leaving me stranded on the side of the road

My preference is to speed up the natural "capacity learning" of the lbc

But if the later is not possible, then the former may be the only option




If you replaced "all" the cells with better ones, this does not mean the BMS will recognize this. But the car runs so that is significant, right? It is the BMS that controls what access you have to the pack. It is this you must get onboard with.

As far as your "gain 15% SOH equates to 25% increase in range" statement? Need a LOT more clarification on how you came about that math. The other thing to consider is SOH is not a statement of capacity, ahr is.

If I am not mistaken, the BMS reset is a relatively simple matter of jumping a few contacts but that is just a vague memory and I have no idea how to go about it. If the range is that important, I would suggest getting the bridge device and honoring the work of the people before you.
[/quote]

Ok, that 25%. Yeah, SOC meter is not linear in car. I take it you use LEAF Spy?
 
Yes, I use leafspy pro. But I do not believe it has an option to update the SoH or Ahr.

Thanks anyway
 
Ok, here is some additional information that may be useful

Yesterday I ran the re-packed traction battery to empty. The last power in the battery was below power limited (turtle) mode. I travelled about 8km after power limit, then ran the last power out using the heater, lights, a/c, seat heaters, demister. That took about 20 minutes at 3.5kw current draw according to leafspy. At shut-down, leafspy reported pack voltage of 335V and I could not re-start the car in drive mode

A full re-charge cycle yielded the following data

Energy into the car (in-line meter) 18.0kwhr. This agrees with charge time x current (excluding the final balancing ramp-down), so I am confident that this amount of energy was delivered to the vehicle

Energy into the car (leafspy) 13354whr

Energy remaining (leafspy) 12.8kwhr

SoH and Gids have not increased as I thought they might with this 0 - 100% charge cycle

So it appears that the battery accepts the expected increase in energy, but leafspy does not report it. I assume leafspy gets its data from lbc and vcm. So I will just have to accept that battery re-packing has hidden energy and it is safe to run down to empty.
 
Home evse at 2.4kw for 7 hours to 94%. Charge rate had not ramped down at this point. (7 x 2.4) / 94% = 17.87kwhr to full = agrees with in line meter

Additional info that may/may not be relevant

Battery charged to 100% (dashboard gauge) and 97.1% (leafspy)

Current flow into car (in line meter) 2410W

Current flow into car (leafspy) 1800W
 
xafalcon said:
Home evse at 2.4kw for 7 hours to 94%. Charge rate had not ramped down at this point. (7 x 2.4) / 94% = 17.87kwhr to full = agrees with in line meter

Additional info that may/may not be relevant

Battery charged to 100% (dashboard gauge) and 97.1% (leafspy)

Current flow into car (in line meter) 2410W

Current flow into car (leafspy) 1800W

Ok so efficiency around 80%.
 
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